[[pp. 5856-5905]] Diesel Particulate Matter Exposure of Underground Metal and

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

[Federal Register: January 19, 2001 (Volume 66, Number 13)]
[Rules and Regulations]
[Page 5856-5905]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19ja01-18]

[[pp. 5856-5905]] Diesel Particulate Matter Exposure of Underground Metal and
Nonmetal Miners

[[Continued from page 5855]]

[[Page 5855]]

from cardiovascular, cardiopulmonary, or respiratory causes; and lung
cancer.
2. At dpm levels currently observed in underground mines, many
miners are presently at significant risk of incurring these material
impairments due to their occupational exposures to dpm over a working
lifetime.
3. By reducing dpm concentrations in underground mines, the rule
will substantially reduce the risks of material impairment faced by
underground miners exposed to dpm at current levels.
In its response to MSHA's proposals, the NMA endorsed these
conclusions to a certain extent, as follows:

The members of NMA have come to recognize that it would be
prudent to limit miners' exposure to the constituents of diesel
exhaust in the underground environment. [NMA]

A number of commenters, however, urged MSHA to defer rulemaking for
either the coal or M/NM sector, or both, until results were available
from the NCI/NIOSH study currently underway. For example, referring to
the M/NM proposal, one commenter stated:

Vulcan agrees with MSHA that underground miner dpm exposure
needs to be addressed by mine operators. Vulcan agrees with MSHA
that a permissible exposure level (PEL) should be established, but
disagrees that adequate information is currently available to set a
PEL. [Vulcan Materials]

MSHA believes that expeditious rulemaking, in both underground mining
sectors, is necessary for the following reasons:
(1) The NCI/NIOSH study currently in progress will eventually
provide additional information on lung cancer mortality. Non-cancer
health effects, such as sensory irritations, respiratory symptoms, or
premature death from cardiovascular, cardiopulmonary, or respiratory
causes will not be addressed. MSHA believes that these non-cancer
effects constitute material impairments.
(2) NIOSH itself has recommended that, ``* * * given the length of
time to complete this study and the current state of knowledge
regarding dpm exposures and health effects in miners,'' MSHA should
``proceed with rulemaking based on the evidence currently available as
presented in this FR notice.'' [NIOSH testimony by Paul Schulte, dated
5/27/99]
(3) Given the very high exposure levels measured at some
underground mines, miners should not be required to serve as human
guinea pigs in order to remove all doubts about the excess risks of dpm
exposures in underground mines. While additional studies are in
progress, miners should be protected by reducing dpm concentrations to
a level more nearly commensurate with exposures in other industries.
Referring to some commenters' position that further scientific
study was necessary before regulatory action could be justified, a
miner at one of the dpm workshops held in 1995 said:

* * * if I understand the Mine Act, it requires MSHA to set the
rules based on the best set of available evidence, not possible
evidence * * * Is it going to take us 10 more years before we kill
out, or are we going to do something now * * *? (dpm Workshop;
Beckley, WV, 1995).

Similar concern with the risk of waiting for additional scientific
evidence was expressed by another miner, who testified:

* * * I got the indication that the diesel studies in rats could
no way be compared to humans because their lungs are not the same *
* * But * * * if we don't set the limits, if you remember probably
last year when these reports come out how the government used human
guinea pigs for radiation, shots, and all this, and aren't we doing
the same thing by using coal miners as guinea pigs to set the value?
(dpm Workshop; Beckley, WV, 1995).

MSHA shares these sentiments. That is why MSHA considers it
imperative to protect miners based on the weight of existing evidence,
rather than to wait for the results of additional studies.

IV. Section by Section Discussion of Final Rule

This part of the preamble describes the provisions of the final
rule on a section-by-section basis. As appropriate, this part
references discussions in other parts of this preamble: in particular,
the background discussions on measurement methods and controls in part
II, and the feasibility discussions in part V.
The final rule would add nine new sections to 30 CFR Part 57
immediately following Sec. 57.5015. It would not amend any existing
sections of that part.
Many provisions of the final rule are identical to the proposed
rule, but some provisions have been changed. The following table
provides a quick overview of the key changes:

------------------------------------------------------------------------
Section Final rule (changes from proposal)
------------------------------------------------------------------------
57.5060......................... When specified conditions have been
met and various precautions have been
taken (including use of proper PPE),
miners performing certain inspection,
maintenance and repair activities may
be granted permission from MSHA to
work in certain areas where miners
normally work and travel, but where
the dpm concentration limit is
exceeded (not authorized in proposed
rule)
57.5061......................... Compliance sampling must always be
done with submicrometer impactor
(unspecified in proposed rule)
57.5067......................... Engines meeting the applicable EPA
requirements as per a table provided
in the rule may be introduced
underground after rule's effective
date (under proposal, only MSHA
approved engines were so allowed)
------------------------------------------------------------------------

Section 57.5060 Limit on Concentration of Diesel Particulate Matter

Summary. This section of the final rule limits the concentration of
dpm in underground metal and nonmetal mines. It has six subsections.
Subsection (a) provides that 18 months after the date of
promulgation, dpm concentrations would be limited by restricting total
carbon to 400 micrograms per cubic meter of air
(400TCg/m\3\). The reason why the concentration
limit for dpm is expressed in terms of total carbon is explained below.
A total carbon limit of 400TCg/m\3\ is the
equivalent of about 500 micrograms per cubic meter of air of dpm
(500DPMg/m\3\). This limit would apply only for a
period of 42 months; accordingly, it is sometimes referred to in this
preamble as the ``interim'' concentration limit. The final rule is the
same as the proposed rule in this regard.
Subsection (b) provides that five years after the date of
promulgation, the concentration limit would be reduced, restricting
total carbon to 160 micrograms per cubic meter of air
(160TCg/m\3\, or about 200DPMg/
m\3\). This is sometimes referred to in this preamble as the ``final''
concentration limit. The final rule is the same as the proposed rule in
this regard.
Subsection (c) provides for a special extension of up to two
additional years in order for a mine to comply with the final
concentration limit. This special extension is only available when the
mine operator can establish that the final concentration limit cannot
be met

[[Page 5856]]

within the five years allotted due to technological constraints. The
final rule establishes the information that must be contained in the
application for an extension, the procedure to follow to make
application, and the conditions that must be observed during the
special extension period. Subsection (c) of the final rule refers to
this extension as ``special'' because the final rule provides all mines
in this sector with an extension of time (five years) to meet the final
concentration limit. The final rule is the same as the proposed rule in
this regard.
Subsection (d) provides that under certain conditions, a miner
engaged in inspection, repair or maintenance activities in certain
areas of a mine may work in concentrations of dpm in excess of the
applicable concentration limit. Among the conditions that must be met
in order for such work to be permitted is the use of proper personal
protective equipment. This exception was not included in the proposed
rule.
Subsection (e) provides that apart from the extraordinary
circumstances where the use of such controls may be authorized under
subsections (c) and (d), an operator must not utilize personal
protective equipment to comply with either the interim or final
concentration limit. The wording in the final rule clarifies the intent
of the proposed rule, and accommodates new subsection (d).
Subsection (f) provides that an operator must not utilize
administrative controls to comply with either the interim or final
concentration limit. The proposed rule included the same requirement,
but in the final rule this has been separated into a separate
paragraph.
General Comments. Some commenters questioned MSHA's rationale for
establishing concentration limits at this time. They pointed out that a
large scale study by NIOSH of the health risks of dpm exposure is still
on-going. Accordingly, they accused MSHA of acting prematurely, and
urged delaying implementation of any limits until the health risks of
dpm exposure are fully quantified. MSHA was also challenged to justify
the specific numerical values chosen for the limits; several commenters
suggested that these limits are based on unsubstantiated and
unquantified health risks, and that therefore, the levels chosen cannot
be justified. But another commenter suggested that the health risks are
sufficiently documented to justify even lower limits than were
contained in the proposed rule. This commenter suggested 100 g
and 50 g for the interim and final limits, respectively. As
these comments involve questions about the risk to underground metal
and nonmetal miners, they are addressed in Part III of this preamble.
Some commenters also objected to the proposed concentration limits
because they argued that MSHA lacked evidence that the limits were
technologically feasible and economically feasible, and some objected
to the use of unvalidated simulations to demonstrate the feasibility of
compliance. An alternative to concentration limits was proposed wherein
mine operators would ``Examine and adopt technically and economically
feasible methods of preventing potentially hazardous or irritating
exposure to diesel exhaust.'' But another commenter argued that the
metal and nonmetal industry could feasibly meet even lower
concentration limits than those proposed. And another suggested that a
concentration limit alone will not adequately protect miner health
because, given the freedom to choose control options, mine operators
may elect to boost ventilation rather than cut emissions. As these
comments concern feasibility, they are generally discussed in part V of
this preamble.
A number of commenters argued that MSHA should allow operators
considerable additional flexibility dealing with dpm. Some felt
operators should be left complete flexibility on controls, and that a
concentration limit at all was inappropriate. Others argued that the
range of operator choice of controls should include personal protective
equipment as well as administrative controls. These comments are
discussed below in connection with this section (Sec. 57.5060).
Still other commenters argued that concentration limits should not
be proposed, or should be much higher, because they argue MSHA lacks a
method to measure dpm concentrations in underground metal and nonmetal
mines that provides the accuracy, consistency, and reliability that are
needed for compliance determinations. These comments are discussed in
this part in connection with Sec. 57.5061.
Another commenter expressed concern about the interplay between
this rule and those already in effect for diesel gases. This commenter
expressed concern that, in addition to complying with the interim and
final dpm concentration limits, mine operators would be required to
comply with a concentration limit that considers the additive effect of
diesel particulate matter and the principal gaseous emissions from a
diesel engine (carbon monoxide, carbon dioxide, nitric oxide, and
nitrogen dioxide).
MSHA's risk assessment in part III does not specifically evaluate
the possible additive effects of diesel particulate matter and diesel
gases. Accordingly, the agency does not at this time have a basis upon
which to enforce either the interim or final dpm concentration limit in
combination with any other substance or substances, including diesel
exhaust gases. MSHA will, of course, continue to enforce the limits
applicable to diesel gases, but this enforcement will be separate from
the enforcement of the dpm concentration limits under the final dpm
rule. The Agency understands that Canada does consider the additive
effect of diesel exhaust gases and particulate, and will notify the
mining community if it decides to look into this matter further based
upon additional information.
Finally, the Agency notes it received only two comments on a
related matter on which it specifically sought comment--whether to
establish an ``Action Level'' for dpm (63FR 58119). An ``Action Level''
is a defined contaminant level (usually one-half of the compliance
limit) which, if exceeded, triggers actions that must be taken to
effectuate control of the contaminant. In the preamble to the proposed
rule, MSHA noted it had considered the possibility of establishing an
Action Level because the dpm concentration at which exposure does not
result in adverse health effects is not known at this time. If an
Action Level were in place and compliance sampling results exceeded
this level, certain remedial steps, or ``best practices,'' would have
to be initiated by management to reduce exposures, such as limits on
fuel type, idling, and engine maintenance--whatever steps MSHA
determined would be feasible at the Action Level for this sector as a
whole. One comment that addressed this approach recommended against
establishing an Action Level because the commenter was of the view that
no limits at all could be justified at this time based on available
health risk data. The other commenter suggested that an Action Level
should be adopted in lieu of a rule incorporating a concentration limit
requiring mandatory compliance.
After further consideration, MSHA determined it does not have
enough information to proceed with an Action Level at this time,
although it notes that the concept of an Action Level is well
recognized in occupational health protection and included in many other
standards. Furthermore, MSHA determined that these ``best practices''
are technologically and economically feasible for all mines, so there
is no reason to withhold their

[[Page 5857]]

implementation until an Action Level is reached. The rationale for
requiring these ``best practices'' is discussed in more detail later in
this section under ``Meeting the concentration limit: operator choice
of controls.''
Concentration limit expressed as an ``average eight-hour equivalent
full shift airborne concentration.'' MSHA recognizes that work shifts
longer than eight hours are common in the underground metal and
nonmetal mining industry. It is for this reason that MSHA expressed its
concentration limit as an ``average eight-hour equivalent full shift
airborne concentration.'' Health-related standards for airborne
contaminants are typically established on the basis of an eight-hour
work shift. Standard industrial hygiene practice, and MSHA's past
practice for metal and nonmetal health sampling, involve adjusting the
actual measured concentration of an airborne contaminant to an eight-
hour equivalent concentration when work shifts are longer than eight
hours. This adjusts an exposure occurring over an extended workshift
(e.g., 10 or 12 hours) to enable a valid comparison to an established
exposure limit that is based on an 8-hr workshift.
The mathematical formula for making this adjustment is thoroughly
described in the MSHA Metal and Nonmetal Health Inspection Procedures
Handbook. This formula is as follows:
[GRAPHIC] [TIFF OMITTED] TR19JA01.075

When the sampling pump flow rate is expressed in units of liters
per minute, the formula results in a contaminant concentration
expressed in units of mg or g per cubic meter. The factor of
480 minutes is used regardless of actual shift duration so as to adjust
the actual concentration to an eight-hour equivalent concentration that
can be appropriately compared to a standard limit.
MSHA specifically asked for comment on whether a more explicit
definition is required in this regard (63 FR 58183). The agency did not
receive any such suggestions. However, it is apparent that the term may
be confusing to some. For example, one commenter observed that ``miners
working overtime hours would be exposed to more dpm than miners on a
normal eight-hour shift,'' and that a formula to determine eight-hour
equivalency should be included. Another commenter expressed concern
that the final rule would place a restriction on the number of hours or
overtime hours miners could work.
MSHA disagrees with these interpretations of the rule. The only
impact of the rule relative to work hours is the aforementioned
determination of ``average eight-hour equivalent full shift airborne
concentration'' for dpm-exposed miners whose work shifts exceed eight
hours. Although the Agency has no suggestions for a more clear
formulation, it will endeavor to clarify this matter further for
operators in its compliance guide.
Dpm concentration limits expressed in terms of total carbon. The
purpose of the interim and final concentration limits is to limit the
amount of diesel particulate matter; but the limit is being expressed
in terms of a restriction on the amount of total carbon. The reason for
this involves the measurement method that MSHA intends to utilize to
determine the concentration of dpm. As discussed in connection with
Sec. 57.5061(a), the final rule specifies that MSHA will use a sampling
and analytical method developed by NIOSH (NIOSH Method 5040) to measure
dpm concentrations for compliance purposes. Using NIOSH's analytical
method, the amount of total carbon (TC) contained in a dpm sample from
any underground metal and nonmetal mine can be determined; the method
does not directly yield the amount of dpm in a particular sample.
However, as explained in detail in Part II of this preamble, TC
represents approximately 80-85 percent of the total mass of dpm emitted
in the exhaust of a diesel engine. The remaining 15-20 percent consists
of sulfates and the various elements bound up with the organic carbon
to form the adsorbed hydrocarbons. Using the lower boundary of this
range, limiting the concentration of total carbon to 400 micrograms per
cubic meter (400TC g/m\3\) effectively limits the
concentration of whole diesel particulate to about 500 DPM
g/m\3\. Similarly, limiting the concentration of total carbon
to 160TC g/m\3\ effectively limits the
concentration of whole diesel particulate to about 200DPM
g/m\3\. Expressing the concentration limit in terms of total
carbon enables miners, mine operators and inspectors to directly
compare a measurement result with the applicable limit.
Where the concentration limit applies. The concentration limits--
both interim and final--would apply only in areas where miners normally
work or travel. The purpose of this restriction is to ensure that mine
operators do not have to monitor and control dpm concentrations in
areas where miners do not normally work or travel--e.g., abandoned
areas of a mine where, for example, the roof may not be monitored for
safety or ventilation may not be provided. At the same time, it should
be noted that the interim and final concentration limits apply in any
and all areas of a mine where miners normally work or travel--not just
where miners might be present at any particular time.
MSHA generally intends for inspectors to determine which portions
of a given mine are subject to the concentration limit based on whether
normal work or travel activities routinely do, or could occur there,
whether areas are designated as ``abandoned'' on mine maps, whether
areas are made ``off limits'' through the use of signs or barricades,
etc.
MSHA has, however, in the final rule (Sec. 57.5060(d)), explicitly
authorized the Secretary, upon making certain findings and ensuring
that certain protections are in place for miners, to allow miners
engaged in certain inspection, maintenance or repair activities to work
in areas of a mine which are considered areas in which miners normally
work or travel but that exceed the concentration limits. These
situations are discussed immediately below.
Exception: Specific mining activities which may be conducted in
areas which exceed the concentration limit. Although feasible
engineering and work practice controls were found to exist for most
underground metal and nonmetal mining situations, MSHA did determine
that certain maintenance and repair activities might have to be
performed in areas where feasible engineering and work practice
controls may not be capable of maintaining the dpm concentration at or
below the applicable concentration limit. Therefore, in the final rule,
Sec. 57.5060(d) under certain conditions permits miners to work in
areas where the concentration limit is exceeded, and only when
specified precautions have been implemented to protect affected miners.
As explained in

[[Page 5858]]

detail below, principal among these precautions is the use by all
affected miners, of proper personal protective equipment (i.e.,
respiratory protection devices) within the context of a comprehensive
respiratory protection program.
More specifically, Sec. 57.5060(d)(1) permits, with the pre-
approval of the Secretary, employees engaged in inspection,
maintenance, or repair activities to work in concentrations of dpm
exceeding the applicable limit if they are protected by appropriate
respiratory protective equipment. This provision applies only to miners
performing the identified activities, and only when certain mandatory
protections are implemented. If respiratory protective equipment is
used, the final rule requires implementation of a respiratory
protection program consistent with the minimum requirements established
in Sec. 56/57.5005 (a) and (b), which address such factors as
selection, maintenance, training, fitting, supervision, and cleaning.
These requirements include by reference, the elements of a minimally
acceptable respiratory protection program as delineated in the American
National Standard on ``Practices For Respiratory Protection'' (ANSI
Z88.2-1969).
The rule specifies that areas for which a request to allow
employees to work in areas that exceed the concentration limit are
limited to--areas where miners work or travel infrequently or for brief
periods of time for equipment or mine inspection; areas where miners
otherwise work exclusively inside of enclosed and environmentally
controlled cabs, booths and similar structures with filtered breathing
air; and in shafts, inclines, slopes, adits, tunnels and similar
workings that are designated as return or exhaust air courses and that
are also used for access into, or egress from an underground mine.
The standard applies in areas of the mine where miners ``normally''
work or travel. Normally does not equate to frequency, but rather to
the nature of the area. Areas where miners work or travel infrequently
are treated by the rule no differently than areas where miners work or
travel frequently. For example, if a remote pump is checked on a weekly
basis, the area in which that pump is located would be considered an
area where miners normally work or travel, even though the area is
visited infrequently.
Approval to allow miners to work in areas that exceed the
concentration limit would be contingent on the Secretary determining
that engineering controls are not feasible, and that adequate
safeguards would be employed by the mine operator to prevent hazardous
exposure to dpm. The final rule requires mine operators to submit a
plan to the Secretary to justify the infeasibility of engineering
controls, and to explain the circumstances of the job, the location
where work will be performed, resulting dpm exposures, and controls to
be used, including, but not necessarily limited to personal protective
equipment.
In order for MSHA to determine the reasonableness of a mine
operator's request for approval under 5060(d), certain details
regarding the work need to be provided. These include the types of
inspection, maintenance or repair activities planned, the locations of
such activities, the dpm concentrations at these locations, the reasons
why engineering controls would not be feasible, the anticipated
frequency of these activities, the anticipated number of miners
involved, and the safeguards the mine operator will employ to minimize
dpm exposures. These factors will tend to change over time as the mine
develops, as new equipment or procedures are introduced, as ventilation
system parameters change, etc. MSHA believes that an annual updating of
these factors is necessary to insure that approval is granted only
where justified by the actual circumstances.
In essence, this exemption allows the use of personal protective
equipment as a substitute for engineering controls under a limited
number of circumstances. Many commenters suggested MSHA permit the use
of PPE much more broadly in lieu of engineering controls; MSHA's review
and reaction to these comments is discussed below.
One commenter, a mine operator, agreed with MSHA's approach that
stresses engineering controls first and foremost. The commenter stated
that, ``engineering controls, as close to the source of the diesel
emission as possible, must be the first line of DPM exposure control.''
The commenter further suggested that, ``The proposed rule should allow
personal protective equipment to be used as a last resort. The proposed
rule should require written documentation explaining how the mine
determined the appropriate exposure controls. This written
documentation should clearly explain why engineering controls, commonly
used in industry to control diesel emissions, are not technically or
economically feasible.''
Although MSHA has embraced the commenter's basic idea of requiring
written documentation when personal protective equipment is proposed as
an alternative to engineering controls, the final rule includes other
necessary safeguards to insure that this option is used only when
absolutely necessary and that appropriate steps are taken to insure
that respirator wearers are adequately protected. The final rule
requires such plans to identify, at a minimum, the types of anticipated
inspection, maintenance, and repair activities that must be performed
for which there are no feasible engineering controls sufficient to
comply with the concentration limit, the locations where such
activities could take place, the concentration of dpm in these
locations, the reasons why engineering controls are not feasible, the
anticipated frequency of such activities, the anticipated duration of
such activities, the anticipated number of miners involved in such
activities, and the safeguards that will be employed to limit miner
exposure to dpm, including, but not limited to the use of respiratory
protective equipment.
The final rule requires mine operators to utilize all feasible
engineering and work practice controls, however, the exception under
subsection (d) permits such controls to be supplemented with respirator
use in certain limited situations where reliance solely on feasible
engineering and work practice controls would be inadequate to control
exposures below the applicable concentration limit. The proposal's
prohibition on administrative controls under any and all circumstances
is retained in the final rule in subsection (e).
Examples of situations where MSHA believes engineering controls
might not be feasible include cleaning up a roof fall in an exhaust air
course, replacing a conveyor belt idler in a conveyor tunnel that is
carrying exhaust air, or shaft inspection in an exhaust air shaft. The
provisions of subsection (d) are not intended to suggest that MSHA
believes these and similar activities should automatically be
considered exempt from the requirement to utilize engineering and work
practice controls to comply with the concentration limit. Rather, MSHA
recognizes that under certain site specific circumstances, feasible
engineering and work practice controls alone may not be capable of
achieving compliance with the concentration limit. Therefore, MSHA
agrees that respirator use should be permitted if the applications are
sufficiently justified and approved in advance.
MSHA does not intend that plans submitted for advance approval need
to identify specifically and individually

[[Page 5859]]

every activity for which advance approval is sought. The intent is that
plans must identify, in a generic sense, the types of activities and
related circumstances as can reasonably be anticipated, sufficient to
enable the Secretary to determine whether advance approval is
warranted.
Meeting the concentration limit: operator choice of engineering
controls. The final rule contemplates that an operator of an
underground metal or nonmetal mine have considerable discretion over
the controls utilized to bring down dpm concentrations to the interim
and final concentration limits. For example, an operator could filter
the emissions from diesel-powered equipment, install cleaner-burning
engines, increase ventilation, improve fleet management, use traffic
controls, or use a variety of other readily available controls. A
combination of several control measures, including both engineering
controls and work practices, may be necessary, depending on site
specific conditions.
MSHA intends for engineering controls to refer to controls that
remove the dpm hazard by applying such methods as substitution,
isolation, enclosure, and ventilation. MSHA intends for work practice
controls to refer to specified changes in the way work tasks are
performed that reduce or eliminate a hazard, such as traffic controls
(speed limits, one-way travel, etc.), prohibiting unnecessary engine
idling, or designating areas that are off-limits for diesel equipment
operations. As discussed below, the final rule does not permit
utilization of administrative controls as a means of complying with the
dpm concentration limit. In the context of this rule, MSHA intends for
administrative controls to refer to controls that limit a miner's
exposure to dpm by distributing the exposure among other miners through
various work scheduling and worker rotation practices.
Some commenters asserted that implementation of certain dpm control
measures may create other, unrelated health or safety problems. One
example given concerned the complications and safety trade-offs of
increasing ventilation to control dpm concentrations. The increased
ventilation would tend to dry out roadways, causing increased problems
with respirable silica bearing dust exposure. This problem, would, in
turn, require application of greater amounts of water on the roadways
for dust control, which, in turn, would create traction problems for
vehicles. Increased ventilation might also accelerate the drying out of
certain roof strata, creating roof control problems. Another commenter
worried that enclosed cabs can reduce an equipment operator's field-of-
view, and dirt or glare on windows can obscure visibility, possibly
creating safety problems.
MSHA acknowledges that dpm control measures need to be selected and
implemented carefully, both to insure they achieve the desired effect
on dpm concentrations, and to minimize or avoid undesirable effects on
other aspects of the mine's health and safety environment. In most
cases, implementation of a given control will not have any undesirable
effects. In other isolated cases, the undesirable effects of a given
control can most likely be negated through additional work practice
controls or other measures. For example, the increased application of
water on roadways to reduce dust control problems caused by higher
ventilation rates may require that equipment be operated at slower
speeds. Roof control problems resulting from the accelerated drying out
of strata may require a reassessment of the mine's roof control plan,
such as its roof bolting practices. Vehicle operator field-of-view and
visibility problems could be addressed by instituting new traffic
controls, requiring slower speeds, and use of window washers. For these
reasons, MSHA does not wish to explicitly deny operators a particular
type of engineering control because in some circumstances an adjustment
to customary mining practices may have to be made.
Because information on available controls has been described in
other parts of this preamble (part II and part V), further discussion
is not provided here. Mine operators are also directed to the MSHA
``estimator'' model to help them determine which control or combination
of controls would be best able to produce the reduction in dpm
concentrations necessary to comply with the appropriate concentration
limit. The ``estimator'' mathematically calculates the effect of any
combination of engineering and ventilation controls on existing dpm
concentrations in a given production area of a mine. This model is in
the form of a spreadsheet template permitting instant display of
outcomes as inputs are altered. The model and some examples
illustrating its potential utility are described in Part V of this
preamble.
Several commenters expressed disappointment that the proposal did
not embrace what they sometimes referred to as ``MSHA's toolbox
approach.'' In some cases, this appears to mean the commenters want
operators to have the flexibility to use personal protective equipment
and administrative controls, as well as engineering and work practice
controls, to meet the required concentration limits. In other cases,
however, it appears the commenters meant that MSHA should allow them
the discretion not only to choose the controls they wish, but to choose
whether or not to use controls at all. In other words, to these
commenters, the ``toolbox approach'' means voluntary implementation of
controls without enforcement of a concentration limit.
By way of background, in 1997, MSHA published a pocket-sized
handbook called, ``Practical Ways to Reduce Exposure to Diesel Exhaust
in Mining---A Toolbox.'' This handbook describes and discusses a
variety of emission control equipment, methods, and strategies, both in
terms of laboratory emissions testing and in-mine experience. The
rationale for a ``toolbox approach'' to controlling diesel emissions is
explained in the handbook. ``A toolbox offers a choice of tools, each
with a specific purpose. One tool after another may be used to find a
solution to a problem, or several tools may be tried at the same time.*
* * Reducing exposure to diesel emissions lends itself to a toolbox
approach because no single method or approach to reducing exposure may
be suitable for every situation.'' Since its publication, this
handbook, which is referred to simply as the ``MSHA toolbox'' or
``toolbox'' has become quite well known and is widely used in the
mining industry.
Commenters who urged MSHA to adopt a ``toolbox approach'' in its
rulemaking praised the approach taken in MSHA's publication, and
indicated that they had successfully implemented some of the control
strategies discussed. They urged MSHA to maintain this flexibility. One
commenter suggested that, ``The toolbox is just simply best practices,
if you would. If we're doing this, this, and this, then we're doing all
we can without enforcement.* * * That's what a toolbox is. A toolbox is
not an enforcement tool.''
The MSHA Toolbox was issued before this rulemaking, in which, after
considering all the evidence, MSHA has concluded that miners are at
significant risk of material impairment at the concentration levels
still found in underground metal and nonmetal mines. When MSHA makes
such a finding, it is required to act to protect miners to the extent
feasible. MSHA has concluded that requiring operators to comply with a
concentration limit using engineering controls is necessary to protect
miners and feasible for the mining industry as a whole, while still

[[Page 5860]]

providing underground metal and nonmetal mine operators with maximum
flexibility to address this problem. Thus, MSHA believes the final rule
does incorporate the ``toolbox approach'' by allowing mine operators to
choose, from among numerous alternatives, the mix of control measures
most suitable for the site specific conditions at a given mine--
provided that the controls bring exposures down to the required limit.
MSHA has determined that certain types of controls discussed in the
toolbox--PPE and administrative controls--are not considered acceptable
ways to meet a concentration limit. PPE does not reduce the
concentrations of a contaminant in the environment, though such
equipment does offer limited protection to miners who must work in
areas where the applicable concentration limit cannot be achieved using
feasible engineering or work practice controls. The rule permits PPE to
be used to protect miners in those limited situations where it permits
work to take place despite dpm concentrations in excess of the
concentration limit (special extension of time to meet final
concentration limit under paragraph (c), discussed below, and special
permission to perform inspection, maintenance and repair activities in
areas that exceed the concentration limit under paragraph (d),
discussed above.) Administrative controls (e.g., limiting the hours
worked by a particular miner in a high concentration area) simply
spread risk among miners. The reasons for MSHA's position in this
regard are discussed in detail below.
MSHA has also determined that certain other types of dpm control
measures discussed in the toolbox must be implemented at all
underground metal and nonmetal mines that use diesel equipment,
regardless of the dpm concentration level, to minimize miner risks.
These ``best practices'' include such requirements as low sulfur
content diesel fuel, limits on unnecessary idling of diesel engines,
maintenance standards, and a requirement for newly introduced engines
to be MSHA approved or meet certain EPA standards. MSHA's rationale for
why it is mandating such ``best practices'' is summarized below.
Further detail is provided in the preamble to the proposal (63FR
58119), and in the sections of this Part which discuss the individual
practices themselves (diesel fuel (Sec. 57.5065(a)), maintenance
(Sec. 57.5066), and engines that are MSHA approved or meet EPA
standards (Sec. 57.5067).
In the proposal, MSHA explained that it had considered implementing
an ``Action Level'' for dpm, possibly at a level one-half of the final
concentration limit, or 80TC g/m\3\ because the dpm
concentration at which exposure does not result in adverse health
effects is not known at this time. Under this approach, when dpm levels
exceeded the Action Level, implementation of certain ``best practice''
controls, such as limits on fuel types, idling, and engine maintenance
would have been required. However, this approach was not incorporated
into the proposal, nor has it been incorporated into the final rule.
MSHA determined it does not have enough information to proceed with an
Action Level at this time, although it notes that the concept of an
Action Level is well recognized in occupational health protection and
included in many other standards. Instead, MSHA determined that these
``best practices'' would be required for all mines at all times.
MSHA followed this course for several reasons, including: (1)
Sampling by both mine operators and MSHA would have been much more
frequent under an approach incorporating an Action Level; (2) tracking
equipment maintenance requirements would have been much more
complicated, as diesel equipment could move from an area of the mine
where the dpm concentration was less that the Action Level, to another
area where the Action Level had been exceeded; (3) these ``best
practices'' are already in place, and have proven to be workable and
practical in coal mines; (4) given the history of lung problems
associated with the mining industry, and considering that these
practices were determined to be economically and technologically
feasible for the industry as a whole, a more protective course seemed
prudent; and (5) a number of the work practices appear to have
significant benefits, such as improving the efficiency of maintenance
operations.
One commenter suggested that other ``best practices'' related to
mine ventilation should be mandated in the final rule. This commenter
recommended requiring mine operators to provide details on the design
and operating parameters of auxiliary ventilation systems, that they be
required to utilize an appropriate air measurement and recording
program, and that they properly attend to uncontrolled recirculations
and leakages. MSHA believes that existing ventilation regulations
adequately address these concerns, and that mine operators, in
utilizing a ``toolbox approach'' to implement dpm control measures,
have the option of incorporating ventilation system improvements if
they are judged to be feasible, practical, desirable, and appropriate
to the site specific conditions at a given mine. Thus, MSHA did not
include a mandate to use such ventilation ``best practices'' in the
final rule.
Concentration limit: time to meet. As noted, the dpm limitation
requires metal and nonmetal mines to reduce total carbon concentrations
in areas where miners normally work or travel to 160 micrograms per
cubic meter of air (equating to about 200 micrograms of dpm per cubic
meter of air.) Sec. 57.5060 provides for an extension of time for
underground metal and nonmetal mines to meet the concentration limit.
Mines do not have to meet any limit for the first 18 months after the
final rule is promulgated. Instead, this period will be used to provide
compliance assistance to the metal and nonmetal mining community to
ensure it understands how to measure and control diesel particulate
matter concentrations in individual operations. Moreover, the rule
provides all mines in this sector an extension of three and a half
additional years to meet the final concentration limit established by
Sec. 57.5060(b). During this extension, however, all mines will have to
bring total carbon concentrations down to 400 micrograms per cubic
meter, equating to a limit of 500 micrograms per cubic meter in dpm.
Comments on the implementation schedule for the concentration
limits focused on the technological and economic feasibility of
complying within the time frames established. Commenters expressed the
view that the rule is technology forcing, and that the mining sector of
the economy is too small to justify the expense by manufacturers
(mining equipment, diesel engines, aftertreatment devices, etc.) to
develop the necessary products to enable mine operators to fully comply
by the deadlines contained in the final rule.
MSHA provided these phase-in times for meeting the interim and
final concentration limits after carefully reviewing comments on the
economic and technological feasibility of requiring all mines in this
sector to meet the applicable limits using available controls. This
review is presented in Part V of this preamble. MSHA has studied a
number of metal and nonmetal mines in which it believed dpm might be
particularly difficult to control. The Agency has concluded that in
combination with the ``best practices'' required under other provisions
of the

[[Page 5861]]

final rule (Secs. 57.5065, 57.5066 and 57.5067), engineering and work
practice controls are available that can bring dpm concentrations in
all underground metal and nonmetal mines down to or below
400TC g/m\3\ within 18 months. Moreover, the Agency
has concluded that controls are available to bring dpm concentrations
in all underground metal and nonmetal mines down to or below
160TC g/m\3\ within 5 years. The Agency has
concluded that it is not feasible to require this sector, as a whole,
to lower dpm concentrations further, or to implement the required
controls more swiftly.
Despite its conclusions on the feasibility of these timeframes for
the underground metal and nonmetal industry as a whole, MSHA has
included a provision in the final rule to allow an additional two years
for mines experiencing difficulty in complying due to technological
problems. A discussion of this special extension follows.
Special extension. Pursuant to Sec. 5060(c), an operator may
request more than five years to comply with the final concentration
limit only in the case of technological problems. In light of the risks
to miners posed by dpm, however, the Agency has concluded that the
economic constraints of a particular operator are not an adequate basis
for a further extension of time for that operator, and the final rule
does not provide for any extension grounded in economic concerns.
Moreover, if it is technologically feasible for an operator to reduce
dpm concentrations to the final limit within the established five year
compliance period, no extension would be permitted even if a more cost
effective solution might be available in the future for that operator.
However, the Agency has determined that if an operator can actually
demonstrate that there is no technological solution that could reduce
the concentration of dpm to 160TC g/m\3\ within
five years, a special extension would be warranted.
Extension application. Sec. 57.5060(c)(1) provides that if an
operator of an underground metal or nonmetal mine can demonstrate that
there is no combination of controls that can, due to technological
constraints, be implemented within five years to reduce the
concentration of dpm to the limit, MSHA may approve an application for
an extension of time to comply.
Such a special extension is available only once, and is limited to
2 years. In this regard, MSHA does not anticipate that an extension
will automatically last 2 years, and the agency will closely scrutinize
applications to determine how much time is really required to implement
a technological solution. To obtain a special extension, an operator
must show that diesel powered equipment was used in the mine prior to
publication of the rule, demonstrate that there is no off-the-shelf
technology available to reduce dpm to the limit specified in
Sec. 57.5060, and establish the lowest concentration of dpm attainable.
In this regard, the Agency reiterates that cost is not a consideration;
thus, simply because a more cost-effective solution will become
available in the future is not an acceptable reason for an extension.
One commenter questioned whether it is reasonable to limit mine
operators to one special extension when the necessary technology to
comply with the concentration limits does not exist today. This
commenter suggests a five to ten year compliance schedule is more
realistic to allow time to develop the technology and to phase in the
replacement of equipment. MSHA believes that very few, if any,
underground metal and nonmetal mining operations should need a special
extension, based on the feasibility information discussed in part V of
this preamble. Despite this information, the final rule makes specific
provision for a special extension for the very few mines that might
experience technical problems that cannot be foreseen at this time. In
the unlikely event any mines experience such technical problems, MSHA
believes that a two year extension, in addition to the five years
granted in the final rule for all mines, will be sufficient for them to
achieve compliance.
The final rule further requires that to establish the lowest
achievable concentration, the operator must provide sampling data
obtained using NIOSH Method 5040 (the method MSHA will use when
determining concentrations for compliance purposes; this sampling
method is further discussed in connection with Sec. 57.5061(a)).
The application would also require the mine operator to specify the
actions that are to be taken to ``maintain the lowest concentration of
diesel particulate achievable'' (such as ensuring strict adherence to
an established control plan) and to minimize miner exposure to dpm
(e.g., such as providing and requiring the use of suitable respirators
at mines or areas of mines under extension). MSHA's intent is to ensure
that personal protective equipment is permitted only as a last and
temporary resort to bridge the gap between what can be accomplished
with engineering and work practice controls and the concentration
limit. It is not the Agency's intent that personal protective equipment
be permitted during the extension period as a substitute for
engineering and work practice controls that can be implemented
immediately.
Filing, posting and approval of extension application. The final
rule requires that an application for an extension be filed no later
than 6 months (180 days) in advance of the date of the final
concentration limit (160TC g/m\3\), and a copy of
the extension be posted at the mine site for the duration of the
extension period. In addition, a copy of the application would also
have to be provided to the designated representative of the miners.
The application must be approved by MSHA before it becomes
effective. While pre-approval of plans is not the norm in this sector,
an exception to the final concentration limit cannot be provided
without careful scrutiny. Moreover in some cases, the examination of
the application may enable MSHA to point out to the operator the
availability of solutions not considered to date. MSHA notes that it
received no comments on this requirement for pre-approval.
While the final rule is not explicit on the point, it is MSHA's
intent (as set forth in the preamble to the proposed rule, 63 FR 58184)
that primary responsibility for processing of the operator's
application for an extension will rest with MSHA's District Managers.
This ensures familiarity with the mine conditions, and provides an
opportunity to consult with miners as well. At the same time, MSHA
recognizes that District Managers may not have the expertise required
to keep fully abreast of the latest technologies and of solutions being
used in similar mines elsewhere in the country. Accordingly, and again
consistent with the preamble to the proposed rule, the Agency intends
to establish, within its Technical Support Directorate a special panel
to consult on these issues and to provide assistance and guidance to
its District Managers. In the preamble to the proposed rule (63 FR
58184) the Agency requested comment on whether further specifics
regarding this approach to approving applications for special
extensions should be incorporated into the final rule, however, no such
comments were received.
The rule specifies that a mine operator shall comply with the terms
of any approved application for a special extension, and provides that
a copy of the approved application be posted at the mine site for the
duration of the application.

[[Page 5862]]

Personal protective equipment and administrative controls. In the
proposal, mine operators were expressly forbidden to use personal
protective equipment (e.g., respirators) or administrative controls
(e.g., job rotation) to comply with either the interim or final dpm
concentration limit. MSHA's rationale for these provisions was that
limiting individual miner exposure through the use of respirators or
job rotation would not reduce the airborne concentrations of dpm in the
mine. Rather, in the proposal, MSHA chose to incorporate the widely
accepted industrial hygiene concept of ``hierarchy of controls'' which
places the highest priority on eliminating or minimizing hazards at the
source through implementation of engineering and work practice
controls.
The ``hierarchy of controls'' paradigm regards administrative
controls and the use of personal protective equipment to be inherently
inferior methods of controlling contaminant exposures in the workplace.
Support for this position is virtually universal in the field of
industrial hygiene. Patty's Industrial Hygiene and Toxicology (Vol I,
General Principles) states, ``Evidence of the importance of engineering
control of the work environment among the various alternative solutions
to industrial hygiene problems is found in every current industrial
hygiene text: all list the possible solutions in priority fashion as
engineering controls, administrative controls, and as a last resort,
use of personal protective equipment.'' The National Safety Council's
Fundamentals of Industrial Hygiene states, ``Engineering controls
should be used as the first line of defense against workplace hazards
whenever feasible. Such built-in protection, inherent in the design of
a process, is preferable to a method that depends on continual human
implementation or intervention.''
This text goes on to describe administrative controls as, ``not as
satisfactory as engineering controls,'' and notes that such controls
``have been criticized by some as a means of spreading exposures
instead of reducing or eliminating the exposure.'' This latter
statement is particularly relevant to dpm, and to carcinogens in
general, because administrative controls, such as job rotation, result
in placing more workers at risk. Among the reasons Patty's Industrial
Hygiene and Toxicology recommends that a given chemical should not be
controlled by administrative reduction of exposure time is that it may
be a carcinogen.
In the proposed rule, MSHA prohibited administrative controls as an
acceptable dpm control method because they fail to eliminate the
exposure hazard and result in placing more miners at risk. Since MSHA
determined that compliance with the interim and final dpm concentration
limits was feasible for the underground metal and nonmetal mining
industry as a whole using exclusively engineering and work practice
controls, the Agency logically chose to prohibit personal protective
equipment as a compliance option as well.
In the Preamble to the proposed rule, MSHA stated that it intended
that the normal meaning be given to the terms personal protective
equipment and administrative controls, and asked for comment as to
whether more specificity would be useful. MSHA noted that it assumed
the mining community understands, for example, that an environmentally
controlled cab for a piece of equipment is an engineering control and
not a piece of personal protective equipment.
Numerous commenters took issue with the proposal's prohibition on
administrative controls and personal protective equipment as compliance
options. They noted that both administrative controls and personal
protective equipment are accepted industrial hygiene exposure control
methods that should be permitted under the rule. Most commenters agreed
that engineering controls would be the preferred option for reducing an
occupational health exposure, but that engineering controls sufficient
to reduce dpm concentrations below the applicable concentration limit
might not be the most cost-effective approach, and more importantly,
that engineering controls may not be feasible in all situations. They
argued that prohibiting administrative controls and personal protective
equipment would, as a result, place mine operators in an impossible
compliance dilemma.
It is significant to note that the commenters did not disagree with
MSHA's fundamental reasoning for using the ``hierarchy of controls''
concept as the basis for prohibiting administrative controls and
personal protective equipment. Likewise, there was no direct
disagreement with MSHA's endorsement of the widely accepted industrial
hygiene principle that administrative controls are inappropriate in the
case of exposure to carcinogens because job rotation will expose more
miners to the hazard.
Rather, commenters argued that administrative controls and personal
protective equipment should be permitted simply to give mine operators
greater flexibility in dealing cost effectively with a workplace
contaminant, and because certain situations exist where no feasible
engineering control would be available to enable compliance with the
concentration limit.
Regarding the question of affording greater operator flexibility, a
typical commenter observed that, ``If MSHA's goal is protection of
miners, in the context of a viable and profitable industry, it should
encourage flexible control approaches to the control of dpm exposure,
and not penalize operators for using all effective means available--
including administrative controls and PPE.'' Another commenter asked
MSHA to, ``reconsider the use of personal protective equipment as a
cost effective solution when appropriate.'' MSHA responds to these
comments by noting that it did incorporate compliance flexibility into
the requirements for this rule. As noted earlier under the discussion
on ``Meeting the concentration limit: operator choice of engineering
controls,'' mine operators do have considerable freedom to choose the
control, or combination of controls necessary to achieve and maintain
compliance with the applicable concentration limit in their mines.
However, this freedom is not total, particularly with respect to
administrative controls and personal protective equipment. Operator
flexibility, convenience, or cost effectiveness are not acceptable
bases for permitting dpm control methods that are widely acknowledged
to be inherently inferior to engineering and work practice controls.
Regarding the question of the feasibility of controls, several
commenters argued that there are situations where engineering controls
are either economically infeasible, technologically infeasible, or
both. Some typical examples of these comments include a mining company
that objected to, ``the Agency's continued downgrading of
administrative controls and the use of personal protective equipment in
favor of considerably more expensive, presently infeasible, engineering
controls.'' Another commenter complained that, ``the standard must be
attained with engineering controls alone,'' and that, ``personal
protective equipment and other means cannot be used even where
compliance with engineering controls is not feasible.'' Still another
commenter observed that, ``The proposal is not [economically or
technologically] feasible for metal mines * * * which are designed
specifically for use of diesel equipment. In these

[[Page 5863]]

mining scenarios, use of electric equipment is not cost-effective, and
elimination of diesel equipment would eliminate the process for which
the mines were designed.''
The question of economic feasibility will be discussed separately
from the question of technological feasibility. MSHA acknowledges that
administrative controls or the use of personal protective equipment may
be less costly than engineering or work practice controls in certain
situations. However, a difference in cost between two approaches is
simply that--a difference in cost. MSHA does not regard a cost
difference per se as prima facia proof that an approach is economically
infeasible simply because a less expensive alternative exists.
Commenters also questioned MSHA's compliance cost estimates,
asserting that compliance costs will actually be much higher. MSHA's
compliance cost estimates are discussed in the REA. However, in answer
to this comment, MSHA determined that exclusive reliance on engineering
and work practice controls are economically feasible for the
underground metal and nonmetal mining industry as a whole (with the
exception of the situations addressed in Sec. 57.5050(d)). Thus, MSHA
rejects the argument that administrative controls and the use of
personal protective equipment should be permitted based on
consideration for economic feasibility.
Regarding the question of the technological feasibility of
engineering and work practice controls, the high number of comments
addressing this issue suggested that the underground metal and nonmetal
mining industry considered it to be of vital importance. Despite their
number, however, none of these comments identified specific equipment
or mining situations where exclusive reliance on engineering or work
practice controls to achieve and maintain compliance with the
applicable dpm concentration limit would be impossible due to
technological infeasibility.
In the preamble to the proposed rule, MSHA provided extensive
information on how mine operators might use a computer program known as
the ``Estimator'' to conduct assessments of controls that might be
necessary to deal with problems in individual mines, and requested
comments based on such specific information. The comments that were
received were critical of the ``Estimator'' because it produces an
estimate of average dpm concentration in a given area, not the specific
concentration that might exist at a specified sampling location; and
because its accuracy depends on the quality of the input data, which is
suspect due to the perceived inherent inaccuracy of the dpm sampling
methods which must be used to obtain the input data.
Regarding the first criticism, MSHA notes that the average dpm
concentration in a given area, which is the output obtained from the
``Estimator,'' is a more accurate indicator of the potential dpm hazard
than a specific concentration that might exist at a specified sampling
location. Since compliance is based on a shift weighted average
concentration produced by diesel equipment that is normally in constant
motion throughout the shift, the average dpm concentration in a given
area is a better predictor of compliance or noncompliance than a
determination of specific concentration that might exist at a specified
sampling location. It might also be advisable to consider relocating a
miner who, by virtue of their specific work location, is thought to be
at risk of being exposed to a concentration of dpm that is greater than
the average for that area (for example, move the miner from being in
the direct line of the exhaust stream). Finally, MSHA notes that the
``Estimator'' is just that, a means of estimating dpm concentration. It
was never claimed that this model could predict dpm concentrations with
pinpoint accuracy. However, in verification testing of the model, MSHA
has observed good agreement between predicted and measured dpm
concentrations (as discussed in part II, section 3 of this preamble).
Regarding the second criticism, MSHA notes that users have the
option of inputting actual dpm data, or estimating such values. If
users desire to input in-mine measurements of dpm concentrations, MSHA
is confident that dpm sampling and analysis using the NIOSH Method
5040, as described elsewhere in this preamble, will accurately
represent actual dpm concentrations.
Nonetheless, MSHA reevaluated the feasibility of engineering and
work practice controls as the exclusive means of complying with the
applicable dpm concentration limits. This reevaluation identified
potential compliance problems related to performing certain inspection,
repair, and maintenance work if only engineering and work practice
controls were permitted as means of achieving compliance. Therefore,
the Agency has adjusted the final rule to allow such work, when
sufficiently justified and preapproved by the Secretary, to be
performed using personal protective equipment as a supplement to
engineering and work practice controls. But apart from these very
limited situations, the Agency has concluded that the use of
engineering controls to meet the concentration limit is both
economically and technologically feasible for the underground mining
industry as a whole, and in light of the health risks to miners, and
the superiority of engineering controls, the Agency has concluded that
they (and not PPE or administrative controls) must be utilized to meet
the concentration limit.

57.5061 Compliance Determinations

Summary. This section of the final rule establishes the criteria
for determining compliance with the concentration limits. It has three
subsections.
Subsection (a) provides for compliance sampling to be performed by
MSHA directly, requires that such compliance sampling be done in
accordance with the other requirements of this section, and further
provides that a single such sample will be adequate to establish a
violation. This is consistent with the proposed rule.
Subsection (b) provides that MSHA will collect dpm samples using a
respirable dust sampler equipped with a submicrometer impactor, and
analyze such samples for the amount of total carbon (TC) using NIOSH
Method 5040 (or by using any method of collection and analysis
subsequently determined by NIOSH to provide equal or improved accuracy
for the measurement of dpm in underground metal and nonmetal mines).
This is like the proposed rule except that the final rule explicitly
requires a submicrometer impactor to be used in collecting all dpm
compliance samples in underground metal and nonmetal mines.
Subsection (c) provides for MSHA inspectors to determine the
appropriate sampling strategy for compliance determinations--personal
sampling, occupational sampling, or area sampling--based on the
circumstances of the particular exposure or exposures to be evaluated.
This provision was not explicitly stated in the proposed rule; it was,
however, stated in the preamble to the proposed rule as MSHA's intent.
The final rule makes explicit MSHA's discretion in this regard.
As discussed in more detail in Part II, section 3, an important
factor in the agency's decision as to which sampling practice to
utilize in a particular situation, and how the sampling should be
conducted (e.g., how far away from a smoker or source of oil mist), is
a careful review of other sources of total carbon in the environment to
be

[[Page 5864]]

sampled which could cast doubt on whether the sample result was based
solely on the amount of dpm present. MSHA will provide guidance in this
regard to metal and nonmetal inspectors and the mining community--based
on the information noted already in Part II, section 3 of this
preamble, such new information as may be developed, and continued
experience in this regard--so as to avoid wasting the limited resources
of the Agency and its counsel, the Mine Safety and Health Review
Commission, and the underground metal and nonmetal mining community by
taking compliance samples whose validity is questionable.
Numerous comments were received on this section--addressing the
validity of single samples for determining compliance with an
occupational health standard; the accuracy, precision, appropriateness,
and practicality of using the NIOSH Method 5040 for determining dpm
concentrations for enforcement purposes; and the legitimacy of using
area sampling to determine compliance with a health standard. These
comments, and MSHA's response to them, are discussed below.
Single sample compliance determination. Pursuant to
Sec. 57.5061(a), a single dpm sample showing that the applicable TC
concentration limit has been exceeded on any individual shift will
constitute a citable violation. Such a violation will also trigger
further action pursuant to Sec. 57.5062, as discussed below in
connection with that section.
As is standard practice with other health compliance measurements,
MSHA intends to account for normal variability in the sampling and
analytical process by allowing a margin of error in the sampling result
before issuing a citation. This margin of error will be based on the
accuracy of the sampling and analytical method (Method 5040) used to
measure the total carbon (TC) concentration in the mine environment,
after correcting for potential interferences.
The variability associated with Method 5040, as expressed by the
relative standard deviation (RSD), decreases with increased load on the
filter. Based on a laboratory experiment, NIOSH has determined that, at
a TC concentration as low as 23 g/m\3\, the variability
associated with an 8-hour sample using Method 5040 and a pump flow rate
of 2.0 L/min is approximately 8.5 percent. (NIOSH Manual of Analytical
Methods, Method 5040, Issue 2, 1998)
MSHA will issue a citation for exceeding the applicable
concentration limit only when such a citation can be issued at a
confidence level of at least 95 percent. Each measurement made for
purposes of compliance determination may be adjusted, if necessary, to
compensate for any expected biases due to interferences such as tobacco
smoke and oil mist. To account for sampling and analytical variability
associated with Method 5040, the adjusted measurement will then be
compared to the appropriate level established in Sec. 57.5060
multiplied by an ``error factor.'' The error factor will be calculated
so as to achieve the required 95-percent confidence that a violation
has actually occurred. Based on the standard normal distribution for
measurement errors, this will be 1 + 1.645 times the variability of the
sampling and analytical method, as expressed by its RSD.
For example, assuming the 8.5-percent limit on the RSD established
by NIOSH under laboratory conditions, the error factor would be 1 +
1.645 x .085 = 1.14. Suppose MSHA takes a sample during the interim
period when the limit is 400TC g/m\3\. Then, if
expected interferences are negligible, MSHA would cite noncompliance
only if the TC measurement exceeded 1.14 x 400 = 456 g/m\3\.
MSHA recognizes that measurement uncertainty may be higher for
samples collected under mining conditions than under laboratory
conditions. Therefore, MSHA intends to base the margin of error
required to achieve a 95-percent confidence level for all noncompliance
determinations on samples collected under field conditions. The Agency
anticipates that the sampling and analytical error factor will be
somewhere between 1.1 and 1.2. The Agency will, however, be governed by
the actual data obtained to establish an appropriate margin of error.
Several comments were received regarding the value of the error
factor for dpm sampling using NIOSH Method 5040. One commenter asserted
that it will be impossible to establish a meaningful error factor,
stating, ``* * * there is insufficient information available to
quantify the margin of error with any level of certainty.'' Another
commenter expressed confusion with respect to the various ways in which
measurement uncertainty was quantified in the proposal. This commenter
argued as follows:

MSHA states on page 58116 that the 5040 Method meets NIOSH's
accuracy criteria that measurements come within 25% of the
concentration at least 95% of the time. This standard is for a known
particle size distribution in a laboratory setting, not a mine
environment. Then on page 58184 states that, ``the variability
associated with the Method 5040 to be approximately 6% (one relative
standard deviation)''! These do not compare! Then it states MSHA
will issue a citation if the measured value was 10% over the
established level! There is a contradiction somewhere in the MSHA
proposal--how can MSHA take 25% NIOSH laboratory criteria and shrink
it to 6% in a mining environment?

This commenter has apparently misunderstood the NIOSH Accuracy
Criterion. Any unbiased method for which the RSD is known to be less
than 12.75 percent meets the criterion, because any RSD less than 12.75
percent implies (assuming no measurement bias) that measurements will
come within 25 percent of the true value at least 95 percent of the
time. An RSD of 6 percent meets the NIOSH accuracy criterion, simply
because 6 percent is less than 12.75 percent. In order to achieve 95-
percent confidence that a specific measurement demonstrates
noncompliance, a 6-percent RSD would, nevertheless, have to be
multiplied by a 1-tailed 95-percent confidence coefficient of 1.645,
yielding the 10-percent adjustment to which the commenter was
referring. Therefore, these quantities are internally consistent. As
stated earlier, however, MSHA intends to base its estimate of the RSD
on data appropriate for field conditions in underground mining
environments.
Another commenter suggested that the NIOSH Method 5040 is prone to
excessive errors because it is ``complex and requires highly skilled
technicians.'' The inherent capacity of the method to produce accurate
results was criticized by one commenter who stated, ``* * * it is not
possible to evaluate the accuracy of the method. In fact, the method
has been shown to produce massive errors when side-by-side samples and
control filters are analyzed. Even blank filters produce high and
widely-varying readings for TC.''
Based on MSHA's extensive experience using NIOSH Method 5040 and
related sampling practices, the Agency is confident that such sampling
and analysis will meet or exceed MSHA's accuracy criteria. This is
discussed in detail in Part II, section 3, and later in this section
under ``Using NIOSH Method 5040 for compliance determinations.''
Regarding the issue of uncertainty in the sampling and analytical
process for field measurements, MSHA has not yet completed its
determination of an appropriate error factor for this method. As noted
above, MSHA will determine an appropriate factor and apply it when
enforcing the applicable compliance

[[Page 5865]]

limit. As a matter of general practice, however, the Agency does not
include error factors in occupational health rules, since the accuracy
of measurement methods may change over time. When this determination is
made, the error factor, along with its derivation, will be promptly
communicated to the underground metal and nonmetal mining industry
through the appropriate channels.
MSHA recognizes that in recent years courts have closely
scrutinized Agency actions to ensure they are consistent with the
requirements of the Administrative Procedures Act and, in MSHA's case,
with the requirements of the Mine Safety and Health Act as well. Courts
have held that certain actions, traditionally regarded as enforcement
policies issued at an agency's discretion, require notice and comment
and even the development of feasibility analyses. MSHA has carefully
considered its obligations in light of these precedents and has
concluded that the determination of a margin of error to be allowed
before issuing a citation remains among the type of actions left to
Agency discretion. To require the Agency to go through rulemaking each
time such an error factor is established or updated based upon improved
sampling or analytical methods would not serve the best interests of
the mining community. Therefore, MSHA wishes to emphasize that the
Agency does not regard the determination of an appropriate margin of
error as a necessary part of this rulemaking, but rather as strictly a
matter of enforcement policy. As noted explicitly in the rule, the
Agency is retaining discretion to switch to better techniques should
NIOSH certify that they provide ``equal or improved accuracy for the
measurement of diesel particulate matter in'' underground metal and
nonmetal mines. (Sec. 57.5061(b))
Notwithstanding its decision not to be explicit in this standard
about the error factor to be used, MSHA recognizes the strong interest
the underground metal and nonmetal mining community has in this issue
and will ensure the matter is fully discussed with that community
before the concentration limits are scheduled to go into effect. In
working with this community on diesel particulate matter controls (see
the history of this rulemaking in Part II of this preamble), the Agency
has repeatedly demonstrated its commitment to good communications in
this regard--e.g., the workshops, the advance and final circulation of
the diesel toolbox, the use of the Agency's web site and direct
notification in appropriate cases.
As explained elsewhere in this preamble, MSHA has determined that
it is feasible for underground M/NM mines to maintain dpm
concentrations at or below the limits specified in Sec. 57.5060 on each
and every shift, everywhere that miners normally work or travel, with
the exception of the circumstances defined in Sec. 57.5060(d).
Therefore, MSHA will protect miners' health to the maximum extent
feasible by citing a violation whenever a single sample demonstrates
that the limit has been exceeded on a full shift at any appropriate
sampling location. This single-sample enforcement strategy is
consistent with all other occupational health enforcement practices in
the metal and nonmetal sector. As per long-standing policy in this
sector, single out-of-compliance samples for dust (e.g., silica-bearing
respirable dust, total nuisance particulate, etc.), gas (e.g., CO,
NO2, solvent vapors, etc.), mist (e.g., cutting oil mist,
spray paint, etc.), fume (e.g., welding fumes, fumes from melting
furnaces, etc.), and noise are all considered citable violations of the
respective standards. Nevertheless, the Agency decided it would be
best, in this rulemaking, to avoid any possible ambiguity in this
regard by explicitly stating in the rule itself that a single sample by
the Agency would provide the basis for a citation. MSHA highlighted
this matter in the preamble of its proposed rule (63 FR 58117, part of
Question and Answer 12).
Some commenters suggested that MSHA should collect numerous samples
and base noncompliance determinations on the average value of all
samples collected. These commenters argued that a single sample is not
a statistically valid representation of the subject's ``typical'' or
``normal'' exposure to the contaminant. The commenters noted that a
single sample, if taken on a randomly selected work day, could result
in an unusually high measurement (unusual with respect to a ``typical''
or ``normal'' day). Therefore, a single sample could give rise to a
noncompliance determination, even if the environment being sampled is
in compliance on most shifts. These commenters contended that such a
sample was ``unrepresentative'' of typical exposure concentrations and
should not, therefore, be used as a basis for a noncompliance
determination.
MSHA recognizes that the day-to-day exposure of a miner will not be
constant and that on some days the sample collected over a single shift
may be lower than the miner's long term average and on other days
higher. However, MSHA has several compelling reasons for considering
noncompliance on any individual shift to be a citable violation of the
dpm concentration limit.
First, MSHA has identified significant risks associated with short-
term dpm exposures (i.e., exposures over a 24-hour period). As
documented in Part III of this preamble, adverse health effects
associated with short-term exposures include (1) acute sensory
irritations and respiratory symptoms (including allergenic responses)
and (2) premature death from cardiovascular, cardiopulmonary, or
respiratory causes. These risks alone would fully justify enforcing the
concentration limits established in Sec. 57.5060 on each and every
shift.
Second, the concentration limits that MSHA has established are not
expected to fully protect miners from these risks or from the excess
risk of lung cancer associated with chronic dpm exposure. Instead, they
are based on what can be feasibly achieved at this time to control dpm.
By requiring compliance with the concentration limit on each shift
measurement, it is MSHA's intent to protect miners to the maximum
extent feasible.
Third, it is not MSHA's objective, when sampling for compliance
determination purposes, to estimate average dpm concentrations for any
period greater than the shift sampled or for any mine location other
than the location sampled. Some commenters confused the objective of
estimating cumulative exposures for purposes of risk assessment with
the objective of limiting cumulative exposures for purposes of risk
management. MSHA's objective is to limit exposures to protect miners
against both short- and long-term effects. It is not practical for MSHA
to track miners' cumulative exposures over an occupational lifetime.
Therefore, as a practical matter of enforcement policy, MSHA can best
protect miners from both the health risks associated with acute
exposures and from the excess lung cancer risk due to chronic dpm
exposure by limiting exposure on each shift wherever miners normally
work or travel.
In addition, MSHA wants to emphasize that compliance limits in the
metal and nonmetal sector, whether personal exposure limits or
concentration limits, apply to every individual work shift. Every full-
shift exposure, not just the typical, or ``average'' exposure, must be
in compliance with the limit. Basing compliance on the typical, or
``average'' shift would permit frequent or sustained exposures to the
contaminant at concentrations significantly higher than the compliance
limit.

[[Page 5866]]

Although MSHA's dpm compliance limit was not derived from any
corresponding ACGIH TLV, the explanation of the proper interpretation
and application of TLV's provided in the 1999 TLV's and BEI's booklet
(American Conference of Governmental Industrial Hygienists, 1999), is
relevant to this discussion. Compliance limits are specifically
intended to be applied over a conventional eight-hour work day and
forty-hour workweek, and not to the average exposure received during a
series of consecutive work shifts or workweek. Although an allowance is
made in some instances for calculating exposures on the basis of a
workweek average concentration, MSHA believes such an exception should
not apply to dpm because of (1) the seriousness of associated health
risks (such as lung cancer and premature death from cardiovascular,
cardiopulmonary, or respiratory causes) and (2) the significant risk of
adverse health effects associated with short-term exposures).
The only circumstance in which a single, out-of-compliance sample
would not be used as the basis for a non-compliance determination is if
the sample itself were considered invalid; for example, an inspector
following an improper sampling procedure. MSHA is of course concerned
primarily with the health and safety of miners so the magnitude of any
citation for a single out-of compliance sample will take into account
the actual risk posed to miners.
MSHA's policy on health inspections requires inspectors to
rigorously follow established sampling procedures to ensure the
validity of samples collected. As a practical matter, MSHA will not
sample for diesel particulate at the tailpipe of any diesel powered
equipment in metal and nonmetal underground mines. As discussed below,
MSHA's sampling strategy for determining operator compliance is
established in paragraph (c) of Section 57.5062. That section
specifically states that MSHA will conduct personal sampling,
occupational sampling, and/or area sampling, depending upon the
circumstances of the particular exposure. Because MSHA has an
environmental exposure limit, MSHA is interested in obtaining the level
of diesel particulate in the environment where miners normally work or
travel. In the alternative, MSHA may conduct personal sampling where
circumstances necessitate it. For example, if a mine operator has a
miner working inside a cab and there are no other workers in that area
working outside the cab, MSHA will conduct personal sampling of the cab
operator and not conduct environmental sampling outside the cab in the
same area of the mine. Moreover, MSHA's sampling would be conducted
inside the cab rather than outside the cab. On the other hand, if there
are miners working outside the enclosed cab, MSHA will sample the
environment to determine the level of exposure to dpm for these miners.
Also, if an operator has a miner who is operating a shuttle car, and
that miner is replaced by another miner during that shift, MSHA intends
to place the sampler on the shuttle car in the vicinity of the miner
and not at the tailpipe. However, in no case will area sampling be
performed closer than five feet to a piece of operating diesel
equipment, and no tailpipe sampling will be performed to determine
compliance with any concentration limit.
Among other precautions, sampling equipment is maintained and
operated in strict accordance with manufacturer recommendations, and
pumps are calibrated before and after samples are collected. Sampling
media are blank-corrected, and all laboratory handling and analytic
procedures are in accordance with AIHA laboratory certification. Sample
integrity is ensured through chain-of-custody seals. If any breach in
procedure occurs, all affected samples are invalidated.
In order to assure compliance with the limit, mine operators need
to implement controls sufficient to ensure that the entire range of
concentration values is always safely below the compliance limit. The
purpose of both MSHA sampling and mine operator monitoring is to
verify, on an on-going basis, that this limit is always met on every
shift.
When mine operators implement effective engineering controls, the
range of the concentration values becomes narrower so that once control
of dpm is demonstrated, it is unlikely that the concentration limit
will be exceeded.
MSHA believes the same justification for determining noncompliance
based on a single sample applies to dpm as to other contaminants and
noise. Therefore, MSHA has retained the provision permitting a
noncompliance determination to be based on a single sample.
Using NIOSH Method 5040 for compliance determinations. Pursuant to
paragraph (b) of section 5061 of the final rule, MSHA will collect dpm
samples for compliance using a respirable dust sampler equipped with a
submicrometer impactor, and analyze such samples for the amount of
total carbon using NIOSH Method 5040 (or by using any method of
collection and analysis subsequently determined by NIOSH to provide
equal or improved accuracy) for the measurement of dpm in underground
metal and nonmetal mines. As noted above, this is like the proposed
rule except that the final rule explicitly requires that a
submicrometer impactor be used in collecting all dpm compliance samples
in underground metal and nonmetal mines.
Section 3 of part II of this preamble discusses alternative methods
for measuring dpm concentrations, and reviews the many comments MSHA
received on this topic. As noted in that discussion, methods other than
NIOSH Method 5040 do not at this time provide the accuracy required to
support compliance determinations at the concentration levels required
to be achieved under this rule. Moreover, after a careful review of the
comments and hearing record, the available technical information
submitted in response to MSHA's proposed rule, and the results of
studies performed by agency experts to ascertain the veracity of those
comments and submissions, MSHA has determined that NIOSH method 5040
provides an accurate method of determining the total carbon content of
a sample collected in any underground metal or nonmetal mine when a
submicron impactor is used with the otherwise prescribed sampling
procedure, and when sampling strategies avoid sampling under
circumstances that could compromise the integrity of the analytical
process. Accordingly, MSHA will use this method for determining TC
concentrations for compliance purposes, and the rule has been
specifically amended to require that such samples be taken with a
submicron impactor.
As indicated in the discussion of the proposed rule (p. 58129),
utilizing the submicron impactor--a device that limits particles
entering the sampler to those less than 0.9 micron in size when
operated at a flow rate of 1.7 LPM--does cause a reduction in the
amount of dpm that can enter the sampler, since some dpm is larger than
0.9 microns. Thus, in making this amendment, MSHA recognizes that
underground metal and nonmetal miners will be exposed to more dpm than
will be ascertained by these compliance measurements. However, for the
reasons noted in section 3 of Part II, MSHA has determined that
requiring use of the impactor is the only way to ensure that certain
potential interferences (sources of total carbon other than dpm) are
avoided at this time. Thus, to ensure the integrity of the sampling
method, the agency has determined that it must use such an impactor.

[[Page 5867]]

One commenter suggested that, in addition to basing concentration
limit compliance determinations on samples collected pursuant to
Sec. 57.5061, samples collected and analyzed in accordance with
Sec. 7.89 should also be used as a basis for compliance determinations.
Section 57.5061 is the compliance determination for the ambient
concentrations in the mine. Based on the ventilation being supplied,
the number of engines being used, the condition of the engines, the
duty cycle of the machines, the sample will show if the mine is in
compliance with the dpm standard. Section 7.89 is the laboratory test
for the diesel in engine in the lab to measure the raw dpm from the
engine. The Sec. 7.89 test data is used to calculate the particulate
index for a single engine. Section 7.89 data can give the mine operator
an idea of the dpm being emitted from the single engine and can use
this data in the ``Estimator'' to calculate an estimated dpm ambient
concentration. However, as explained elsewhere in the preamble, this is
an estimate to set up proper ventilation when adding other pieces of
equipment or deciding on which engine to buy. The section 7.89 dpm
concentration does not take into account the duty cycle of the engine.
Section 7.89 tests all engines on a specific test cycle. Section 7.89
test data can only be used to estimate dpm, cannot be used to know
exactly what the concentration is in a mine at any given time. The test
in 57.5061 is used for that determination. MSHA believes this procedure
is inappropriate for determining compliance with the concentration
limits and provision for doing so has not been included in the final
rule.
Sampling strategy--personal, occupational, and area sampling.
Subsection (c) of section 5061 provides for MSHA inspectors to
determine the appropriate sampling strategy for compliance
determinations: personal sampling (attaching a sampler to an individual
miner within the miner's breathing zone), area sampling (sampling at a
fixed location where miners normally work or travel), or occupational
sampling (locating the sampler on a piece of equipment where a miner
may work).
Personal sampling is well understood in the metal and nonmetal
sector because it is commonly used by MSHA to determine compliance with
TLV's for silica-bearing respirable dust, welding fumes, and
other airborne contaminants. Area sampling is less well known in this
sector, but it is used by MSHA for compliance determinations in some
situations, such as where miners are exposed to a contaminant having a
ceiling limit. Occupational sampling is not well known in the metal and
nonmetal sector because it is not currently used by MSHA for compliance
determinations in this sector. However, MSHA does employ occupational
sampling in the coal sector for compliance determinations.
Occupational sampling is a method which measures the exposure of an
occupation to a given contaminant, as opposed to personal sampling,
which measures the exposure of an individual, or area sampling, which
measures the contaminant concentration at a fixed location throughout
the working shift. All three methods determine contaminant
concentration on a shift weighted average basis (see previous
discussion of ``Concentration limit expressed as an average eight hour
equivalent full shift airborne concentration'' under Sec. 57.5060). In
occupational sampling, a full-shift sample is collected from the
working environment of the occupation. The sampling apparatus (sample
pump, size selection devices, sample filter, etc.) remains in the
environment of the work position being sampled rather than with the
individual miner, even when miners change positions or alternate duties
during the shift.
A very common example of where occupational sampling would be the
appropriate sampling method is where the sampling objective is to
determine the full shift exposure of the operator of a particular piece
of equipment, but where two or more individuals alternate operating the
equipment. Personal sampling would capture both the exposure received
while the equipment is being operated, as well as the exposure received
while performing other duties. Area sampling would be limited to
measuring the contaminant concentration in the general area where the
equipment is operated, but would not capture the operator's exposure.
In this example, occupational sampling, with the sample apparatus
remaining in the cab or operator's compartment of the equipment
throughout the shift, would be the only sampling method that could
satisfy the sampling objective.
As noted above, the provision for utilizing either personal
sampling, area sampling, or occupational sampling was not explicitly
stated in the proposed rule. It was, however, clearly stated in the
preamble to the proposed rule as MSHA's intent; indeed, a specific
Question and Answer was devoted to the topic. (63 FR 58117, Question
and Answer 14; the topic is further explored at 63 FR 58185). Moreover,
in explaining its adoption of a ``concentration limit'', MSHA noted
that its intention was to emulate the approach taken with coal mine
dust, where inspectors have similar discretion (63 FR 58184) in the
preamble to the proposal). Accordingly, the mining community was fully
informed in this regard. The topic was the subject of considerable
discussion at the hearings and received considerable comment.
After evaluating the comments, and reviewing the verification data
on possible interferences discussed in Part II of this preamble, MSHA
determined that its proposed position in this regard should be
explicitly incorporated into the final rule. At the same time, as a
result of the comments, the Agency has refined its thinking as to when
various types of sampling would be appropriate. The Agency will provide
further information in this regard in its compliance guide, but is
using this opportunity to inform the underground metal and nonmetal
mining community of its current views on how it will initially approach
this matter.
Numerous commenters expressed concern about the proposed rule's
provision for using either personal sampling or area sampling for
determining compliance with the concentration limit for dpm. They
pointed out that area sampling was a departure from previous
enforcement practice in metal and nonmetal mines. They also questioned
whether it was appropriate to use area sampling to determine compliance
when there may be no one exposed (or very limited miner exposure) to
dpm at the time and in the location where the area sample is taken, as
well as in situations where miners work in enclosed cabs with filtered
breathing air, and in other areas where engineering controls are not
feasible. One commenter also argued that sampling at a fixed location
(area sampling) and then equating the results with a personal exposure
was invalid.
Commenters also asserted that the superiority of personal sampling
for quantifying worker exposures is a commonly accepted industrial
hygiene principle. Some commenters noted that in underground mines
which use mobile diesel equipment, the positions of diesel-powered
vehicles with respect to intake and return air streams vary from hour
to hour. Therefore, they asserted, it is virtually impossible to obtain
meaningful information from stationary instruments. One commenter
stated that area sampling was appropriate as a screening tool to
determine whether personal sampling would be warranted, or to evaluate
the effectiveness of controls, but that it

[[Page 5868]]

should not be used to determine compliance with a mandatory limit.
In responding to these comments, MSHA would like to emphasize to
the metal and nonmetal mining community, as it did in the preamble to
the proposed rule, that while the concept of a concentration limit is
new for this sector, it is a well established concept in the mining
industry, and has been implemented for many years with respect to coal
dust. Questions about whether a particular sampling method are
appropriate in a given situation have been raised and resolved many
times.
Moreover, the courts have upheld MSHA's use of area sampling for
enforcing compliance. In a 1982 decision (American Mining Congress v.
Secretary of Labor, Nos. 80-1581 and 80-2166), the U.S. Court of
Appeals, Tenth Circuit ruled that the decision to employ area sampling
for respirable dust compliance determinations was a reasonable exercise
of MSHA's discretion and authority. The court stated:

``Nothing in the record supports the conclusion that either type
of sampling provides a perfect measure of exposure to respirable
dust. Since there is no perfect sampling method, the Secretary has
discretion to adopt any sampling method that approximates exposure
with reasonable accuracy. The Secretary is not required to impose an
arguably superior sampling method as long as the one he imposes is
reasonably calculated to prevent excessive exposure to respirable
dust. On this record, the difference between area and personal
sampling is not shown to be so great as to make Secretary's choice
of an area sampling program irrational. Keeping in mind that our
task is not to determine which method is better, we hold that the
Secretary's choice of area sampling over personal sampling is not
legally arbitrary and capricious.''
``We are not unmindful that area sampling may effectively
require lower dust levels than might be required under a personal
sampling program.''
``The fact that in theory the regulation may require operators
to maintain a dust level below [the limit] in its person-by-person
impact does not render the regulation arbitrary and capricious. We
repeat that all proposed sampling methods are less than perfect and
are designed to provide only estimates of actual exposure. Since
measurement error is inherent in all sampling, the very fact that
Congress authorized a sampling program indicates that it intended
some error to be tolerated in enforcement of the dust standard. The
method selected by the Secretary, while perhaps more burdensome in
its impact on mine operators than other methods, is not beyond the
scope of his discretion.''

In addition to affirming MSHA's discretion to employ area sampling on
the basis that it can be ``reasonably calculated to prevent excessive
exposure,'' the court also observed that area sampling can be
considered superior to personal sampling for enforcement purposes:

``The area sampling program has several advantages over a
personal sampling program. The most important advantage is that area
sampling not only measures the concentration of respirable dust, it
allows identification and thus control of dust generation sources.
Control of dust at the source will obviously contribute to reducing
the level of personal exposure. By contrast, the results of personal
samples do not allow identification of dust sources due to the
movement of miners through various areas of the mine during the
course of a working shift. Thus, while a personal sampling system
makes possible the identification of discrete individuals who have
been overexposed, it does nothing to ensure reduction of dust
generation because the source of the dust cannot be determined.
Therefore, it clearly appears that area sampling can rationally be
found to be superior to personal sampling as a means of enforcing
(as opposed to merely measuring) compliance with [the standard].''

Although this decision relates specifically to respirable dust, it is
clear that the Court of Appeals did not find that area sampling is
inherently unreliable. Moreover, the logic expressed by the Court in
describing the application of area sampling to respirable coal mine
dust applies equally to dpm. Both are solid particulates that are
produced from discrete sources during mining and are transported via
the mine's ventilation system and inhaled by miners.
Accordingly, the fact that some in the metal and nonmetal sector,
or some not engaged in mining at all, may not be familiar with this
approach does not make it invalid or inappropriate.
Implementation by MSHA of its discretion. For the reasons noted
above, MSHA has determined that personal sampling, occupational
sampling, and area sampling are all viable sampling methods, and that
inspectors should have the discretion to utilize whichever sampling
strategy is appropriate in a given situation to determine compliance
with the concentration limit for dpm. Accordingly, all three approaches
are permitted in the final rule.
The Agency will provide further information about how these
approaches should be used for dpm sampling in its compliance guide;
however, it is using this opportunity to inform the underground metal
and nonmetal mining community of its current views on some common
situations.
For example, one commenter noted that an area sample could be taken
adjacent to where a piece of diesel equipment was accelerating at low
RPM, which is the time that an engine is working at its lowest
efficiency. This commenter expressed concern that such a sample could
indicate that the applicable dpm concentration was exceeded, even
though the duty cycle as a whole for that equipment might be in
compliance. MSHA believes this situation shouldn't result in a
violation, because such an area sample would be taken for an entire
shift, not just for the short time period when the piece of diesel
equipment passes by the sampler.
Moreover, MSHA recognizes that it would not provide an accurate
measure of the concentration of dpm to place a sampler in the area
immediately around a machine's tailpipe when no workers would be in
that location for any great length of time. An area sample would not be
taken in that manner. But if a worker were assigned to work in a
location on or immediately adjacent to diesel equipment, a personal or
occupational sample might well be appropriate to determine if the limit
is being exceeded for that worker or for such occupation.
Similarly, the agency would not consider it appropriate to conduct
area sampling for compliance determinations in areas where dpm
exposures, if any, would be infrequent and brief; in areas where miners
work exclusively inside enclosed cabs; and in shafts, inclines, slopes,
adits, tunnels and similar workings that are designated as return or
exhaust air courses and that are also used for access into, or egress
from an underground mine.
Examples of the first situation would be work areas that are
visited infrequently and briefly, such as a remote pump that needs to
be checked weekly, or a remote area where roof conditions need to be
inspected at periodic intervals. These areas would clearly be subject
to the concentration limit because miners ``normally work or travel''
there. Area sampling in such areas would be inconsistent with the
regulation's intent to, `` * * * limit the concentration of [dpm] to
which miners are exposed * * *,'' because exposure would occur for only
a few minutes per week, or possibly less.
Examples of the second situation would be production areas or
haulageways where the only miners present work inside of enclosed and
isolated cabs with appropriate filtration of breathing air, and
underground crushing stations where crusher operator booths or similar
fixed structures are provided with appropriately filtered breathing
air. Area sampling outside such cabs or structures, which would have
been permitted under the proposed rule,

[[Page 5869]]

would be inconsistent with the regulation's intent to, `` * * *limit
the concentration of [dpm] to which miners are exposed * * *,'' because
miners in these areas are not exposed; they are already protected by an
accepted engineering control. This approach is consistent with MSHA's
intent as stated in the preamble to the proposed rule (63 FR 58184). It
also reflects MSHA's awareness that enclosed cabs may provide many
other important health and safety benefits, such as reducing noise
exposure and reducing exposure to silica bearing respirable dust.
However, as a result of the comments concerning whether NIOSH
method 5040 can effectively be used to determine compliance when miners
are smoking, the agency recognizes that it faces a particular
difficulty in sampling miners when they smoke inside an enclosed cab or
booth, whether such sampling is area, occupational, or personal. As
noted in Part II, section 3, MSHA has verified that sampling using
NIOSH method 5040 immediately adjacent to smokers can undermine the
validity of the sample result--since some of the total carbon detected
may be from the smoke). While MSHA can generally avoid this problem by
not sampling immediately near smokers, as discussed in that section of
this preamble, it does face a problem when the area to be sampled is an
enclosed cab or booth: it can neither sample inside nor outside an
enclosed cab or booth if the subject miner smokes. The Agency intends
to address this problem by obtaining the concurrence of the miner not
to smoke while sampling the environment of the cab.
MSHA is troubled that, under certain circumstances, it will need to
rely on miners voluntarily refraining from smoking in order to perform
compliance sampling for dpm. Since miners are usually free to choose to
smoke if they wish, this need to rely on the voluntarily cooperation of
miners could seriously limit the agency's ability to sample when and
where it desires. Though MSHA has determined that sampling of
nonsmokers would usually be unaffected by the presence of smokers
elsewhere in the mine, there will be situations where sampling of a
specifically targeted area, occupation, or person would be prevented
due to the presence of a smoker at that immediate location. Therefore,
MSHA intends to continue to search for a means to reliably measure dpm
concentrations despite the presence of cigarette, cigar, and pipe smoke
in close proximity to the sampling equipment.
As noted in Part II, section 3, MSHA has determined that samples
analyzed only for elemental carbon are unaffected by the presence of
cigarette smoke. At this time, however, MSHA cannot limit its analysis
to elemental carbon, because no consistent quantitative relationship
has been established between elemental carbon concentration and the
concentration of whole dpm.
MSHA intends to implement any newly developed sampling procedure
and/or analytical method that is capable of directly or indirectly
measuring the concentration of whole dpm in the presence of cigarette,
cigar, and pipe smoke, provided such procedure and/or method is
determined by NIOSH to provide equal or improved accuracy compared to
the NIOSH Method 5040. If MSHA decides that such a change in sampling
procedure and/or analytic method should be adopted, the agency will
utilize standard communication channels to provide specific
notification of its intention in this regard to the underground metal
and nonmetal mining industry. However, MSHA wishes to be clear that, in
accordance with Sec. 57.5061(b), implementing such a change does not
require new rulemaking.
Examples of the third situation include return or exhaust air
courses that are shafts, inclines, slopes, adits, tunnels, etc. which
terminate on the surface, but which are also used for mine access or
egress by mine personnel.
Since the purpose of a return or exhaust air course is to collect
and remove contaminated air from the mine, one would expect such an air
course could contain high dpm levels. However, being a major travelway,
one would naturally consider them to be areas ``where miners normally
work or travel.'' As miners travel into the mine at the beginning of
the shift and out of the mine at the end of the shift through these
mine openings, relatively brief exposures to potentially high dpm
levels could be expected. Full shift area sampling in such a location
would likely indicate dpm levels in excess of the concentration limit.
Should area sampling in such an air course result in a determination of
noncompliance (which would be highly likely), the mine operator would
be required to implement a change of some kind to bring the area into
compliance, such as requiring that miners use a different access to the
mine that is an intake or neutral air course, or that the ventilation
system would need to be changed so that the access in question is no
longer a return or exhaust air course. Since neither of these options
may be feasible, the operator would be placed in an impossible
compliance situation.
In such situations, MSHA believes that it would not be appropriate
to use area sampling; rather, personal sampling would be more
appropriate. Personal sampling would capture the exposure as miners
travel into the mine at the beginning of the shift and depart at the
end of the shift. Since the exposure time is brief, overexposure on a
full-shift basis would be unlikely (assuming dpm levels in the working
places are in compliance). Also, since exposure time is brief, the
health risk associated with the exposure would be minimal.
It should be noted, however, that miners whose jobs require them to
spend significant periods of time in these areas would continue to be
at risk of overexposure if the dpm levels are high. For example, a
haulage truck driver that spends much of the shift driving in and out
of the mine through exhaust air hauling material to a surface dump
point or crusher may need to be protected with an enclosed cab that is
provided with filtered breathing air. Personal sampling on miners who
engage in such activities would reveal the problem.
Another situation requiring clarification as to MSHA's intended
compliance sampling procedures concerns miners who perform multiple
work tasks during a shift. If a miner's work on a given shift includes
a task or tasks for which the sampling procedures would not provide an
accurate measurement of the dpm, MSHA would not use that measurement
for the basis of a compliance determination. An example would be a
miner who begins the shift operating a diesel-powered loader, and who
finishes the shift operating a jack leg drill equipped with an in-line
oil bowl. While operating the loader, MSHA would consider a personal or
occupational sampling procedure to be acceptable for obtaining an
accurate measurement for compliance purposes. However, as noted in
Section II, MSHA would not consider personal or occupational sampling
to be acceptable for sampling a miner who is operating a jack leg drill
equipped with an in-line oil bowl, because there is the potential that
oil mist emitted from the drill may be collected on the sample filter
causing an inaccurate measurement of dpm to be made.
In this case, full shift area sampling would be performed at a
location where the oil mist would not interfere with the measurement of
dpm. If the drilling operation takes place in a different location from
the loading operation (a different stope, for example), MSHA would
consider full shift area sampling in both locations, if appropriate.

[[Page 5870]]

However, if no source of dpm is present at the drilling location, the
inspector would probably choose to sample only the location where the
loader is operating.
The agency considered whether it would be appropriate to deal with
these situations through an amendment of the rule, and decided this
would not be appropriate. The specific facts in a specific situation
should determine the appropriateness of the sampling approach; trying
to lock down this situation or that in the rule would prove very
complex and restrict the flexibility to react to developments in the
industry. The rule reserves to MSHA the flexibility to adjust the use
of sampling approaches for any situation where use of one or another
method might not be appropriate.
At the same time, the Agency wishes to make it clear that in
putting explicitly into the rule that the Agency can use any of the
three methods specified, it intends by that action to ensure that any
policy that would broadly restrict the use of one or another of these
methods would have to be the subject of new rulemaking. Thus, for
example, any policy to significantly restrict the use of area sampling
to enforce compliance with this rule would have to be the subject of
new rulemaking action, as the availability of that method was a key
consideration in MSHA's decision that it could implement a
concentration limit.

Section 57.5062 Diesel Particulate Matter Control Plan

Under the final rule, a determination of noncompliance with either
the interim or final concentration limit prescribed by Sec. 57.5060
would trigger two requirements: first, the operator must establish a
diesel particulate matter control plan (dpm control plan) meeting
certain basic requirements--or modify the plan if one is already in
effect; and second, the operator must demonstrate that the new or
modified plan will be effective in controlling the concentration of dpm
to the applicable concentration limit. The final rule also sets forth a
number of other specific details about such plans, and states that
failure of an operator to comply with the provisions of a plan or to
conduct required verification sampling will be a violation of Part 57
without regard for the concentration of dpm that may be present. In all
respects, this section of the final rule is essentially the same as in
the proposed rule.
Only a few comments were directed specifically at Sec. 57.5062.
Some of those were supportive of the concept, such as the remark by one
mine operator that, ``Generally, the Diesel Particulate Matter Control
Plan (DPMCP) contained in Sec. 57.5062 is well conceived.'' One
commenter noted that once a plan is in place, failure to abide by its
provisions is a citable violation, even if dpm levels are below the
applicable concentration limit. Another commenter recommended that
rather than a single out-of-compliance sample triggering the
requirement to implement a plan, the provisions of Sec. 57.5062 should
not be triggered unless there is a significant history of non-
compliance with the limit. Another commenter questioned why a
determination of non-compliance requires MSHA to obtain only one non-
compliant sample, whereas proof of operator compliance (both with
respect to Sec. 57.5062 and Sec. 57.5071) requires multiple operator
samples. A commenter also observed that a single sample is not
``statistically significant or representative and cannot determine if
the mine is out of compliance.'' The same commenter argued that the
requirements for documenting dpm control plan effectiveness were
unnecessary, burdensome, and duplicated other MSHA requirements.
Triggering plan. Under the final rule, a single out-of-compliance
dpm sample constitutes a citable violation of the applicable
concentration limit and triggers the requirement to implement a diesel
particulate matter control plan. As noted above, one commenter
recommended that a diesel particulate matter control plan should not be
required unless a mine has a significant history of non-compliance with
the applicable dpm concentration limit. MSHA disagrees with the
commenter's position because MSHA does consider a single sample to be a
valid means of determining compliance (see discussion under
Sec. 57.5060 on single sample), and because a ``significant history of
non-compliance'' at a given mine, would almost certainly be accompanied
by significant, prolonged, and repeated exposure of miners to dpm
levels in excess of the applicable concentration limit. Such exposures
cannot be tolerated. When sampling indicates non-compliance, remedial
action consisting of the implementation of a dpm control plan, or
modification of an existing plan, must be initiated without delay. This
will insure a timely reduction in dpm levels, and will help prevent dpm
levels from rising above the applicable concentration limit in the
future.
No advance approval of plans required. Sec. 57.5062 will maintain
the Agency's metal and nonmetal mine plan tradition by not invoking a
formal plan approval process. That is, the plan would not require
advance approval of the MSHA District Manager. As noted in the
discussion of Sec. 57.5060(c) and (d), MSHA is requiring advance
approval for an operator to obtain a special extension of up to 2 years
to meet the final concentration limit, and/or to allow miners
performing inspection, maintenance or repair work to conduct such
activities in areas that exceed the concentration limit. But a plan
required because the limit has been exceeded need not obtain such
advance approval.
In the preamble to the proposal for this Part, MSHA requested
comment from the mining industry as to whether dpm control plans should
require pre-approval by the Agency (p. 58119). The only comment
received was in support of the Agency's proposal that such plans not
require pre-approval.
A dpm control plan would, however, have to meet certain
requirements set forth in the final rule, and as noted in the preamble
to the proposed rule, it would be a violation of Sec. 57.5062 if MSHA
determines that the operator has failed to adequately address each of
the plan's required elements.
Moreover, as discussed subsequently in connection with paragraph
(f) of this section, once in place, a dpm control plan becomes law for
that mine, and an operator must comply with it.
Elements of plan. Under Sec. 57.5062(b), a dpm control plan must
describe the controls the operator will utilize to maintain the
concentration of diesel particulate matter to the applicable limit
specified by Sec. 57.5060. The plan must also include a list of diesel-
powered units maintained by the mine operator, together with
information about any unit's emission control device and the parameters
of any other methods used to control the concentration of diesel
particulate matter.
Relationship to ventilation plan. At the discretion of the
operator, the dpm control plan may be consolidated with the ventilation
plan required by Sec. 57.8520.
Demonstration of plan effectiveness. The final rule would require
monitoring to verify that the dpm control plans are actually effective
in reducing dpm concentrations in the mine to the applicable
concentration limit. Because the dpm control plan was initiated as a
result of a compliance action, the final rule would require the use of
the same measurement method used by MSHA in compliance determinations--
total carbon using NIOSH method 5040--to conduct verification sampling.
As a result, mine operators who are required to establish a dpm control
plan would need to acquire the necessary sampling equipment to conduct
the verification sampling, or arrange for such sampling

[[Page 5871]]

to be conducted for them. As noted in Part II, the necessary sampling
equipment is commercially available.
MSHA recognizes concerns about the commercial availability of the
sampling equipment for NIOSH Method 5040. It is important that
operators know whether they are in compliance with the standard. MSHA
understands that the equipment will be available before this standard
is in effect. MSHA will not use any equipment for sampling for
compliance with this standard that is not commercially available. If
the equipment is not commercially available by the effective date of
the standard it is MSHA's intention not to enforce the dpm levels in
the standard until the sampling equipment is available.
Effectiveness must be demonstrated by ``sufficient'' monitoring to
confirm that the plan or amended plan will control the concentration of
diesel particulate to the applicable limit under conditions that can be
``reasonably anticipated'' in the mine.
The final rule, like the proposed rule, does not specify that any
defined number of samples must be taken--the intent is that the
sampling provide a fair picture of whether the plan or amended plan is
working. Instead, as indicated in the preamble to the proposed rule,
MSHA will determine compliance with this obligation based on a review
of the situation involved. While an MSHA compliance sample may be an
indicator that the operator has not fulfilled the obligation under this
section to undertake monitoring ``sufficient'' to verify plan
effectiveness, it would not be conclusive on that point.
One commenter questioned the fairness of holding operators
responsible for verifying plan effectiveness, the need for
documentation to verify that plans will control dpm to the applicable
limit, and for the requirement that such documentation must be provided
upon request by MSHA. This commenter suggested that mine operators are
already required to show compliance with air quality standards under
Sec. 57.5002, and that further documentation relating to the diesel
particulate matter control plan therefore duplicates existing
requirements.
While it is true that Sec. 57.5002 requires mine operators to
conduct ``dust, gas, mist, and fume surveys'' as frequently as
necessary to determine the adequacy of control measures, this
regulation does not specifically address diesel particulate matter, nor
does it specify that dpm concentrations must be determined using the
NIOSH Method 5040 (as is required in Sec. 57.5062(c)). Thus, compliance
with Sec. 57.5002 will not insure compliance with the intent of
Sec. 57.5062. Section 57.5062(c) also requires that mine operators
demonstrate that dpm concentrations will be controlled to applicable
limits, not only under current conditions (i.e., that a compliant
sample be obtained), but also under reasonably anticipated conditions
in the future.
MSHA disagrees with the commenter's suggestion that ``rigorous
enforcement of existing TLV's and air quality rules, and * *
* utilization of recommendations in the `Diesel Toolbox''' will result
in ``adequate safety levels.'' The 1973 Threshold Limit
Values or TLV's (the TLV©'s incorporated by
reference in Sec. 57.5001, and therefore currently enforceable in
underground metal and nonmetal mines) do not include a limit of any
kind for dpm. It is interesting to note that, as indicated in Table II-
2 of Part II, section 5, the TLV's enforced by MSHA are
derived from recommendations of the American Conference of Governmental
Industrial Hygienists (ACGIH). That organization has recently proposed
a limit for dpm (ACGIH Notice of Intended Changes for 1999) of
50DPMg/m3, well below what is being
established by this rule. As noted in Part V of this preamble, MSHA has
concluded that 50DPMg/m3 is an
unreasonably low limit for dpm concentration in underground metal and
nonmetal mines because MSHA's technological and economic feasibility
assessment indicate that this level cannot be achieved using feasible
control measures.
If a diesel particulate matter control plan is in effect, the final
rule specifies that monitoring must be ``sufficient to verify that the
plan will control the concentration of diesel particulate matter to the
applicable limit under conditions that can be reasonably anticipated in
the mine.'' Again, as conditions and circumstances in the mine change,
the mine operator must demonstrate, on a continuing basis, through
sampling results using NIOSH Method 5040, that compliance with the
applicable concentration limit is consistently achieved.
MSHA believes that dpm control requires a holistic approach. A
piecemeal solution to a dpm problem may result in shifting an
overexposure from one area to another, but not eliminating the problem
entirely. If an overexposure in one part of the mine is addressed by
re-routing more ventilation air to that area, it means another part of
the mine will have to give up some air, possibly causing an
overexposure there. If an overexposure in one part of the mine is
addressed by exchanging a dirty machine for a clean machine, it means
the dirty machine is still polluting somewhere else. In these examples,
the actions taken may simply move an overexposure to a different
location, or they may result in overall compliance. The only way of
knowing for sure whether the problem has actually been solved, is to
consider the effects of a given action on the mine as a whole. That is
what the regulation requires. MSHA does expect operators will focus
their control plans on the areas of the mine in which dpm presents a
hazard to miners.
The reason that MSHA can determine non-compliance based on a single
sample whereas mine operators need multiple samples to demonstrate
compliance is due to the fundamental difference between proving non-
compliance versus proving compliance. For example, proving that at
least one non-compliance condition exists somewhere in a mine requires
only one non-compliant sample result. Proving conditions are fully
compliant everywhere in a mine all the time requires more than one
compliant sample result. The actual number of compliant samples
necessary to prove that every location in the mine is fully compliant
all the time would have to be determined, but it would rarely, if ever,
be only one.
The differences between determining non-compliance versus
determining compliance are incorporated into standard industrial
hygiene practice. For example, regarding the evaluation of the exposure
of a worker over a single day by means of a full-period measurement
(which is MSHA's compliance sampling approach), Patty's Industrial
Hygiene and Toxicology (3rd Edition, 1994) states, ``In that case, the
error variance is determined by only the sampling and analytical error,
and confidence limits tend to be quite narrow.'' By appropriately
accounting for sampling and analytic errors, MSHA will assure, at the
95% confidence level, that an out-of-compliance sample accurately
reflects an out-of-compliance condition in the mine.
This contrasts with the mine operator's need to verify compliance.
Patty's states, ``Usually, however, our concern is with the totality of
a workers exposure, and we wish to use the data collected to make
inferences about other times not sampled. There is little choice;
unless the universe of all exposure occasions is measured, we must
``sample,'' that is, make statements about, the whole based on
measurement of some parts.''
``The American Industrial Hygiene Association has addressed the
issue of

[[Page 5872]]

appropriate sample size (Hawkins et al., 1991) and recommends in the
range of 6-10 random samples per homogeneous exposure group. Fewer than
6 leaves a lot of uncertainty and more than 10 results in only marginal
improvement in accuracy. Also, it is usually possible to make a
reasonable approximation of the exposure distribution with 10 samples
although a rigorous goodness-of-fit test often requires 30 or more.''
Although a single sample is not adequate to demonstrate compliance,
MSHA does not specify in the final rule, a minimum number of samples
that will constitute adequate verification of compliance in all cases.
It is the mine operator's responsibility to determine the appropriate
level of sampling effort and explain the rationale in the diesel
particulate matter control plan.
Like the final rule, the proposed rule provided that verification
sampling would be conducted under conditions that can be ``reasonably
anticipated'' in the mine. The Agency very specifically solicited
comment on ``whether, and how, it should define the term `reasonably
anticipated.' '' (63 FR 58185) The agency noted that with respect to
coal dust, the Dust Advisory Committee recommended that ``MSHA should
define the range of production values which must be maintained during
sampling to verify the plan. This value should be sufficiently close to
maximum anticipated production.'' (MSHA, 1996) For dpm, the Agency
suggested, the equivalent approach might be based on worst-case
operating conditions of the diesel equipment--e.g., all equipment is
being operated simultaneously with the least ventilation. No comments
were received on this point.
Recordkeeping retention and access. Pursuant to section 5062(b), a
copy of the current dpm control plan is to be maintained at the mine
site during the duration of the plan and for one year thereafter.
Section 5062(c) requires that verification sample results be retained
for 5 years. And, section 5062(d) provides that both the control plan
and sampling records verifying effectiveness be made available for
review, upon request, by the authorized representative of the
Secretary, the Secretary of Health and Human Services, and/or the
authorized representative of miners. Upon request of the District
Manager or the authorized representative of miners, a copy of these
records is to be provided by the operator.
Duration. The final rule requires the dpm control plan to remain in
effect for three years from the date of the violation resulting in the
establishment/modification of the plan. Section 57.5062(e)(1) and
(e)(2). MSHA has concluded that operators have sufficient time under
the final rule to come into compliance with the concentration limits;
if a problem exists, maintaining a plan in effect long enough to ensure
that daily mine practices really change is an important safeguard. MSHA
noted its view in this regard in the preamble to the proposed rule; no
comments were received on this point.
Modification during plan lifetime. If a diesel particulate matter
control plan is already in effect at a mine, section 57.5062(a)
requires the mine operator to modify the current plan upon a subsequent
violation of section 57.5060, and to demonstrate the effectiveness of
the modified plan.
Section 57.5062(e)(3) would require the mine operator to
independently initiate the modification of an existing dpm control plan
to reflect changes in mining equipment and/or the mine environment, and
requires the operator to demonstrate the effectiveness of the modified
plan.
It should also be noted that a mine operator, based on dpm sampling
data or other information or analysis, may at any time, modify the
provisions of a dpm control plan to make it less restrictive, provided
sufficient sampling data confirm the plan's continuing effectiveness in
controlling dpm to compliant levels. A modification made in this manner
does not affect the 3-year duration of the plan (end date unaffected).
These plans made by the operator do not require advance approval by
MSHA.
Compliance with plan requirements. Section 57.5062(f) states that
failure by a mine operator to comply with the provisions of a diesel
particulate matter control plan is a violation of the rule, regardless
of the concentration of dpm that may be present at any time. Once an
underground metal or nonmetal mine operator adopts a dpm control plan,
it is considered law for the mine. Section 57.5062(f) specifically
provides that MSHA would not need to establish (by sampling) that an
operator is currently in violation of the applicable concentration
limit under Sec. 57.5060 in order to determine (by observation) that an
operator has failed to comply with any requirement of the mine's dpm
control plan.
One commenter observed that, ``It does seem odd * * * that
Sec. 57.5062(f) contemplates that the mere failure to adhere to the
[dpm control plan] itself is deemed a violation of the regulation--
irrespective of the fact that the exposure to dpm may indeed be less
than the [concentration limit].''
MSHA's rationale for making a mine's dpm control plan law for that
mine derives from the rule's approach to setting control requirements.
MSHA recognizes that every mine faces a unique set of conditions and
circumstances relating to equipment, engines, emission controls,
ventilation, etc. that would make uniform dpm control requirements
across the entire underground metal and nonmetal mining industry
unworkable, impractical, and ineffective. Hence, the final rule, with
just a few exceptions, permits mine operators considerable freedom to
select the mix of dpm control options they believe are necessary to
comply with the applicable concentration limit. An operator can filter
the emissions from diesel-powered equipment, install cleaner-burning
engines, increase ventilation, improve fleet management, or use a
variety of other readily available controls, all without consulting
with, or seeking approval from MSHA.
However, if MSHA sampling indicates non-compliance with the
applicable concentration limit, the rule requires the operator reduce
to writing his or her specific plans for controlling dpm to the
concentration limit and to adhere to that plan. MSHA considers miner
exposure to dpm, a probable carcinogen, as a very serious matter, and
has not established that exposures, even at the concentration limit,
are safe. That is why a single non-compliant sample triggers the
requirement for a compliance plan. The plan lays out the minimum steps
the operator has determined must be followed in that mine to insure
compliance. Failure to adhere to the requirements of the operator-
developed plan must thus be viewed as a failure to take actions that
are necessary for compliance with the concentration limit.
Because of the importance of adhering strictly to an effective dpm
control plan, a means of enforcing such adherence is necessary. The
plan is made law for that mine so that its provisions can be enforced
by MSHA. The plan need not be approved by the MSHA District Manager,
but it is, nonetheless, law for that mine, and any violation of the
plan is therefore a violation of the regulation. As discussed above, an
operator is free to modify a dpm control plan to make it less
restrictive at any time during its life, and as often as desired, as
long as sufficient sampling data confirm the plan's continuing
effectiveness in controlling dpm to compliant levels. MSHA is of course
concerned primarily with the health and safety of miners so the
magnitude of any citation for a

[[Page 5873]]

violation of the plan will take into account the actual risk posed to
miners.
With respect to the required diesel particulate matter control
plan, the mine operator is essentially telling MSHA what steps are
necessary for that mine to comply with the applicable concentration
limit. If MSHA observes a violation of the plan, it is only reasonable
and proper for MSHA to conclude that full compliance is therefore not
possible. If enforcement of the provisions of the dpm control plan
depended upon obtaining an out-of-compliance dpm sample, plan
enforcement would be greatly diminished, both in terms of timeliness
and effectiveness. If such a sample were taken, and found to be out of
compliance, implementation of needed corrective measures would be
delayed because MSHA could not require the mine operator to take
remedial actions until the sample results were obtained from the
analytic laboratory, which could involve several weeks of time. If such
a sample were taken, and found to be in compliance, that fact would not
constitute conclusive evidence that the plan as a whole was fully
effective (see earlier discussion on the need for multiple samples to
establish continuing compliance). Thus, while providing inconclusive
information at best, such a sampling outcome would prevent MSHA from
enforcing a provision of the plan. Regardless of sampling outcome, it
is important to remember that a violation of the plan means the mine
operator did not adhere to the very requirements that were represented
to MSHA by the operator as being necessary for compliance.
It should also be noted that MSHA already has similar enforcement
authority relative to various other plans that are required in the
underground metal and nonmetal sector. Mine operators are required to
prepare plans for such purposes as escape and evacuation, rock bursts,
ventilation, and training. MSHA has the authority to enforce the
provisions of these plans without first verifying that the observed
violation has caused an immediate outcome which itself, is prohibited
by regulation. There is also ample precedent for citing health-related
violations without sampling, such as Sec. 58.620 on drill dust control,
and Sec. 57.5005 on respiratory protection.
The mine operator is required to modify dpm control plans to
reflect changes in mining equipment or circumstances. The mine operator
is also required to modify dpm control plans if the plan proves to be
inadequate, as evidenced by a subsequent non-compliance determination
during the three year period that the plan is in effect. In either
case, the modifications to the original plan become law for that mine,
and violations are subject to enforcement action by MSHA regardless of
dpm concentration.
It is also important to remember that dpm levels are determined by
the complex interaction of numerous factors, such as equipment type,
engine size, type, and horsepower, duty cycles, engine maintenance,
equipment operator training and work practices, fuel and fuel
additives, the characteristics and performance of exhaust filtering
systems, mine ventilation flows, and many others. Effectively
controlling dpm levels throughout a mine requires a systematic approach
that acknowledges the interrelationships and interactions between these
factors to produce the desired end result, which is compliance with the
applicable concentration limit. A determination of non-compliance
indicates that the system of controls has failed. Thus, an effective
permanent solution requires a comprehensive approach which not only
corrects the immediate cause of the non-compliance (an out-of-tune
engine, for example), but also addresses the underlying system failure
(deficient maintenance management, inadequate dpm monitoring,
ineffective equipment operator training, failure to tag equipment
believed to require maintenance, etc.).
The implementation of a dpm control plan avoids piecemeal solutions
that result in a repetitive pattern of mines being in and out of
compliance without ever coming to grips with underlying problems. The
required elements of a dpm control plan force a comprehensive approach,
and facilitate effective, permanent solutions to systemic failures. The
three year duration of such plans insures that the necessary system
changes become institutionalized and integrated into daily mine
practices. This, in turn, will increase the chances that mines will be
in compliance with the applicable concentration limit on a continuous,
on-going basis.
MSHA recognizes that some operators may want to supplement the
compliance plans required by the regulation with additional internal
instructions that provide supplementary protection--i.e., to achieve
concentration levels below those required. MSHA does not want to
discourage such supplemental plans; indeed, it would like to encourage
them. Accordingly, MSHA will, upon request, work closely with mine
operators to help avoid confusion by mine and Agency personnel between
required compliance plans that contain the minimum elements considered
essential to achieve compliance (and whose provisions are therefore
enforceable by MSHA) and non-required supplemental plans that contain
elements the mine operator wishes to implement as a matter of company
policy (but whose provisions are not enforceable by MSHA).

Section 57.5065 Fueling Practices

Summary. This section of the final rule establishes the
requirements for fueling practices in underground metal and nonmetal
mines. Unlike the proposed rule, the final rule has two subsections.
Subsection (a) limits the amount of sulfur that may be contained in
diesel fuel used to power equipment in underground areas, and requires
mine operators to maintain purchase records that verify the sulfur
content of the fuel they use.
Subsection (b) requires that fuel additives used in underground
diesel-powered equipment be restricted to those registered by the U.S.
Environmental Protection Agency.
These subsections of the final rule have not been changed from the
proposed rule.
The practices being required by these two subsections are accepted
industry practices to reduce dpm emissions. They are among the methods
for reducing dpm explicitly included in MSHA's toolbox publication, and
were made requirements for underground coal mines as part of MSHA's
diesel equipment rulemaking. They are among the ``best practices'' for
reducing dpm emissions that MSHA has determined are technologically and
economically feasible for all underground metal and nonmetal mines.
Part II of this preamble contains some background information on these
practices together with information about the rules currently
applicable in underground coal mines.
Low-sulfur fuel. In the final rule, Sec. 57.5065(a) would require
underground metal and nonmetal mine operators to use only low-sulfur
fuel having a sulfur content of no greater than 0.05 percent. This
requirement is identical to that currently required for diesel
equipment used in underground coal mines [30 CFR 75.1901(a)]. Both
number 1 and number 2 diesel fuel meeting the sulfur content
requirement of this rule are commercially available.
Sulfur content can have a significant effect on diesel emissions.
Use of low-sulfur diesel fuel reduces the sulfate fraction of dpm
matter emissions, and

[[Page 5874]]

reduces objectionable odors associated with diesel exhaust.
Another major benefit of using low-sulfur fuel is that the
reduction of sulfur allows oxidation catalysts to perform properly.
Some diesel emission aftertreatment devices, such as catalytic
converters and catalyzed particulate traps, are ``poisoned'' with fuels
having high-sulfur content (greater than 0.05 percent sulfur). MSHA
believes the use of these aftertreatment devices is important to the
mining industry because they will be necessary for many mines to meet
the specified concentration limits. The requirement to use low-sulfur
fuel will allow these devices to be used without additional adverse
effects caused by the high-sulfur fuel.
Several commenters questioned why low-sulfur fuel was mandated,
even for operators who could meet the applicable concentration limit
using other means. MSHA responds by noting that the use of low-sulfur
fuel is one of the ``best practices'' that MSHA requires all mines to
follow, regardless of current dpm levels. Further elaboration on the
rationale for mandating these ``best practices'' was included in the
preamble to the proposed rule (63 FR 58119), and a summary was provided
in this Part under the portion of Sec. 57.5060 that discussed ``Meeting
the concentration limit, operator choice of engineering controls.'' As
noted in those discussions, MSHA is required by statute to reduce a
significant risk to the extent feasible; the use of low-sulfur fuel is
feasible, has not created any problems in the underground coal sector
where it is required as a result of the diesel equipment rule, and its
use will reduce dpm emissions from underground engines.
In the preamble to the proposal (63 FR 58186), MSHA indicated it
did not believe a requirement mandating the use of low-sulfur fuel will
add additional compliance costs. Several commenters contradicted this
conclusion, arguing that the provision requiring low-sulfur fuel would
have an adverse cost impact. One commenter supplied actual cost figures
that showed their fuel costs increased over $18,000 per year after they
switched to low-sulfur fuel. However, it is significant to note that
this increase is quite small on both a cost per gallon of fuel basis
(less than $0.03 per gallon), and a cost per ton basis (about $0.008
per ton), and that this mine had already made the switch to low-sulfur
fuel, apparently because they perceived that the benefits justified the
small additional expense.
As discussed in the Section IV of the PRIA, MSHA determined that
the cost difference between high-sulfur and low-sulfur diesel fuel was
less than $0.02 per gallon in many parts of the country, and in some
areas, there was no difference at all, or a slight cost advantage to
using low-sulfur fuel. Fuel used in over-the-road diesel engines is
currently required by EPA regulations to meet the same 0.05% sulfur
content limit that is being implemented for underground metal and
nonmetal mines. Because over-the-road diesel engines represent the bulk
of the diesel fuel market, such low-sulfur fuel is already readily
available throughout the country. EPA has proposed regulations that
would further reduce allowable fuel sulfur content to 0.0015% for over-
the-road diesel engines. Current MSHA regulations limit the sulfur
content of diesel fuel used in underground coal mines to 0.05%, and the
availability of this fuel in remote coal mining areas has not been a
problem for coal mine operators. As discussed above, MSHA has
determined, based on extensive study of the metal and nonmetal mining
industry, that compliance with the rule is economically feasible for
the industry as a whole. Thus, although the provision requiring use of
only low-sulfur fuel may, in some instances, result in a small cost
increase for some operators, MSHA estimates that on average, the
overall measurable impact is negligible. When they are measurable, it
is because the mine is located in an area where heating fuel has
relatively large market share compared to diesel fuel used for
vehicles. This circumstance is unrelated to mine size. Most mines are
not located in these regions and there is no evidence that small mines
are disproportionately concentrated in these regions.
Fuel additives. Paragraph (b) of this section requires mine
operators to use only diesel fuel additives that have been registered
by the Environmental Protection Agency (40 CFR Part 79). Again, this
rule is consistent with current requirements for diesel equipment used
in underground coal mines [30 CFR 75.1901(c)], and is another of the
``best practices'' that MSHA considers to be feasible for all
underground metal and nonmetal mines. The restricted use of additives
would ensure that diesel particulate concentrations would not be
inadvertently increased, while also protecting miners against the
emission of other toxic contaminants. MSHA has published Program
Information Bulletin No. P97-10, issued on May 5, 1997, that discusses
the fuel additives list. The requirements of this paragraph do not
place an undue burden on mine operators because operators need only
verify with their fuel suppliers or distributors that the additive
purchased is included on the EPA registration list. To assist mine
operators in this regard, EPA's Internet site contains a current
listing of additives registered with EPA. This site can be accessed at
the following address: http://www.epa.gov/oms/regs/fuels/additive/web-
dies.txt. No commenters objected to this requirement.
Idling practices. Proposed paragraph (c) of Sec. 57.5021 would have
prohibited idling of mobile diesel-powered equipment, except as
required for normal mining operations. After further consideration of
all comments received during the comment period, as well as testimony
presented at the public hearings, MSHA has decided to delete this
requirement from the final rule. Therefore, the final rule does not
contain a restriction for operators on idling diesel-powered equipment.
MSHA does, however, recommend as a best practice that mine operators do
not allow miners to idle diesel-powered equipment unnecessarily.
Although commenters generally agreed with MSHA's statement in the
proposal that this requirement would aid in the reduction of dpm
concentrations at the mine, they pointed out that the total amount of
diesel particulate matter emitted from this single source might have
little effect on the levels of dpm in the overall mining environment.
Also, several commenters questioned the need for an idling restriction
in light of the proposed concentration limits established in the
regulation. Additionally, another commenter indicated that the
provision was not necessary because mine operators, in an effort to
comply with the applicable concentration limits, would be forced to
institute work rules to this effect anyway. Moreover, as pointed out by
commenters, nothing in the regulatory language prohibits operators from
voluntarily restricting idling at the mine, eliminating the need to
include this provision. Accordingly, we have deleted proposed paragraph
(c) from the final rule.

Section 57.5066 Maintenance standards.

Summary. This section of the final rule establishes maintenance
standards for diesel-powered equipment operated in underground areas of
metal and nonmetal mines. It has three subsections.
Subsection (a) addresses maintenance of diesel engines, emission
related components, and emission or particulate control devices.

[[Page 5875]]

Subsection (b) institutes a mandatory procedure by which diesel
equipment operators must be authorized and required to tag equipment
they believe requires maintenance in order to comply with subsection
(a) above, for mine operators to insure that equipment so tagged is
promptly examined, and for mine operators to retain a log of tagged
equipment and the corresponding equipment examinations.
Subsection (c) requires that persons maintaining diesel equipment
in underground metal and nonmetal mines be appropriately qualified by
virtue of training or experience, and that mine operators must retain
evidence of the competence of such persons.
The provisions of this section in the final rule are unchanged from
the proposal.
Maintain Approved engines in approved condition. Sec. 57.5066(a)(1)
requires that mine operators maintain any approved diesel engine in
``approved'' condition. Under MSHA's approval requirements, engine
approval is tied to the use of certain parts and engine specifications.
When these parts or specifications are changed (i.e., an incorrect part
is used, or the engine timing is incorrectly set), the engine is no
longer considered by MSHA to be in approved condition.
Often, engine exhaust emissions will deteriorate when this occurs.
Maintaining approved engines in their approved condition will ensure
near-original performance of an engine, and maximize vehicle
productivity and engine life, while keeping exhaust emissions at
approved levels. The maintenance requirements for approved engines in
this rule are already applicable to underground coal mines. 30 CFR
75.1914.
Thus in practice, with respect to approved engines, mine
maintenance personnel will have to maintain the following engine
systems in near original condition: air intake, cooling, lubrication,
fuel injection and exhaust. These systems shall be maintained on a
regularly scheduled basis to keep the system in its ``approved''
condition and thus operating at its expected efficiency.
One of the best ways to ensure these standards are observed is to
implement a proper maintenance program in the mine--but the final rule
would not require operators to do this. A good program should include
compliance with manufacturers' recommended maintenance schedules,
maintenance of accurate records and the use of proper maintenance
procedures. MSHA's diesel toolbox provides more information about the
practices that should be followed in maintaining diesel engines in
mines.
Maintain emissions related components of non-approved engines to
manufacturer specifications. For any non-approved diesel engine,
paragraph (a)(2) requires mine operators to maintain the emissions
related components to manufacturer specifications.
The term ``emission related components,'' refers to the parts of
the engine that directly affect the emission characteristics of the raw
exhaust. These are basically the same components which MSHA examines
for ``approved'' engines. They are the piston, intake and exhaust
valves, cylinder head, injector, fuel injection pump, governor, turbo
charger, after cooler, injection timing and fuel pump calibration.
Engine manufacturers are required to build engines in a manner that
ensures continued compliance with EPA emissions levels and to establish
specifications for adjusting and maintaining these engines to the
engine manufacturer's specifications to ensure that the engines
continue to perform properly and emit acceptable levels of emissions.
As it indicated in the preamble to the proposed rule, the Agency
does not intend that this requirement could be misconstrued as
establishing the basis for ``picky'' citations. It is not MSHA's intent
that engines be torn down and the engine components be compared against
the specifications in manufacturer maintenance manuals (63 FR 58187).
Primarily, the Agency is interested in ensuring that engines are
maintained in accordance with the schedule recommended by the
manufacturer. However, if it becomes evident that the engines are not
being maintained to the correct specifications or are being rebuilt in
a configuration not in line with manufacturers' specifications or
approval requirements, an inspector may ask to see the manuals to
confirm that the right manuals are being used, or call in MSHA experts
to examine an engine to confirm whether basic specifications are being
properly observed.
This explanation of MSHA's intent relative to its enforcement of
this provision was included in the Preamble to the proposed rule,
accompanied by an invitation for comment from the mining industry to
suggest alternative ways to rephrase this requirement so the Agency has
a basis for ensuring compliance while minimizing the opportunity for
overprescriptiveness (63 FR 58187). However, no such suggestions were
received.
Maintain emission or Particulate Control Devices in effective
operating condition. Paragraph (a)(3) requires that any emission or
particulate control device installed on diesel-powered equipment be
maintained in effective operating condition. Depending on the type of
devices installed on an engine, this would involve having trained
personnel perform such basic tasks as regularly cleaning aftertreatment
filters, using methods recommended by the manufacturer for that
purpose, or inserting appropriate replacement filters when required,
checking for and repairing any exhaust system leaks, and other
appropriate actions. This explanation of MSHA's intent relative to
subsection (a)(3) was contained in the preamble to the proposed rule
(63 FR 58187). One comment was received on this subsection from a
commenter who submitted a complete regulatory alternative to MSHA's
proposed dpm rule. The section of this regulatory alternative that
corresponds to subsection (a)(3) of both the proposed and final rules
reads as follows: ``Emission related components of diesel powered
equipment shall be maintained in effective operating condition.'' This
alternative language is functionally identical to both the proposed and
final rules. It incorporates the phrase ``Emission related components
of diesel powered equipment * * *,'' whereas the rules incorporate the
phrase, ``Any emission or particulate control device installed on the
equipment * * *,'' however, the requirement that such equipment,
``shall be maintained in effective operating condition,'' is identical.
Therefore, MSHA concluded that no change from the proposal was
necessary.
Ensuring equipment that may be out of compliance with maintenance
standards is attended to--Tagging. Section 57.5066(b)(1) of the final
rule requires underground metal and nonmetal mine operators to
authorize and require miners operating diesel powered equipment to
affix a visible and dated tag to the equipment at any time the
equipment operator ``notes any evidence that the equipment may require
maintenance in order to comply with the maintenance standards of
paragraph (a) of this section.'' Moreover, Sec. 57.5066 (b)(2) requires
that the equipment be ``promptly'' examined by a person authorized by
the mine operator to maintain diesel equipment, and prohibits removal
of the tag until such examination has been completed. Section 57.5066
(b)(3) requires a log to be retained of all equipment tagged.
In proposing this approach, MSHA noted its view that tagging would

[[Page 5876]]

provide an effective and efficient method of alerting all mine
personnel that a piece of equipment needs to be checked by qualified
service personnel for possible emission problems, and that such a check
is performed in a timely way (63 FR 58187).
The agency noted that the presence of a tag serves as a caution
sign to miners working on or near the equipment, as well as a reminder
to mine management, as the equipment moves from task to task throughout
the mine. While the equipment is not barred from service, operators
would be expected to use common sense and not use it in locations in
which diesel particulate concentrations are known to be high.
The agency noted it was not requiring that equipment tagged for
potential emission problems be automatically taken out of service. The
rule is not, therefore, directly comparable to a ``tag-out''
requirement such as OSHA's requirement for automatic powered machinery,
nor is it as stringent as MSHA's requirement to remove from service
certain equipment ``when defects make continued operation hazardous to
persons'' (see 30 CFR 57.14100). In the Preamble to the proposed rule,
MSHA indicated that it did not think there was a need for something as
stringent as these requirements because, although exposure to dpm
emissions does pose a serious health hazard for miners, the existence
or scope of an equipment problem cannot be determined until the
equipment is examined or tested by a person competent to assess the
situation. Moreover, the danger is not as immediate as, for example, an
explosive hazard.
In the preamble to the proposed rule, MSHA also provided additional
insights into how this approach would be implemented. It noted, for
example, that the tag may be affixed because the equipment operator
detects a problem through a visual exam conducted before the equipment
is started, or because of a problem that comes to the attention of the
equipment operator during mining operations, (i.e., black smoke while
the equipment is under normal load, rough idling, unusual noises,
backfiring, etc.) MSHA also noted it had not defined the term
``promptly'' with respect to how quickly tagged equipment must be
examined by a qualified person, and sought comment on whether it should
define this term--for example, by limiting the number of shifts it
could operate before the required examination is performed (63 FR
58187).
The equipment tagging requirement was the subject of numerous
comments. Most commenters were concerned that equipment operators would
be authorized and required to make judgements about equipment function
(and malfunction) for which they are unqualified, namely, to tag
equipment they believe requires maintenance due to a problem related to
dpm emissions. The commenters argued that, although equipment operators
may be highly skilled in operating equipment, they are not necessarily
qualified to make judgements concerning equipment maintenance
requirements. Even though the regulation would not require tagged
equipment to be removed from service, the commenters were concerned
that such tags would cause unnecessary ``scurrying about of mechanics''
whose time could be more productively spent performing actual needed
maintenance, rather than reacting to tags affixed for reasons that
might be dubious, at best.
Commenters noted that, in addition to unnecessary maintenance
inspections and the possibility of unnecessarily removing equipment
from service, this requirement could result in a safety hazard if a tag
affixed under Sec. 57.14100(c) is mistaken for a tag affixed under
Sec. 57.5066(b)(1). The former addresses safety defects that ``make
continued operation hazardous to persons,'' and it requires the
equipment to be immediately removed from service. The latter relates to
dpm emissions, and does not require the piece of equipment to be
removed from service. If a tag under Sec. 57.14100(c) is mistaken for a
tag under Sec. 57.5066(b)(1), the affected equipment would be allowed
to remain in service, exposing the operator, and possibly others, to
potentially dangerous conditions.
Some commenters suggested that the tagging requirement in the final
rule was completely unnecessary because its intent is already satisfied
by existing Sec. 57.14100, and that for the sake of simplicity,
Sec. 57.5066(b)(1) should be eliminated. Another commenter noted that
Sec. 57.5066(b)(1) was unnecessary because mine operators already have
effective mechanisms in place to identify and correct maintenance
problems on diesel equipment, including emissions-related problems.
Another commenter worried that a citation could be issued if an
inspector believes an operator failed to tag a piece of diesel
equipment with a ``smoky'' exhaust, even if the operator believes the
exhaust is within the normal range. Several commenters speculated that
disgruntled employees would deliberately shut down equipment by tagging
it for an emissions check.
Several commenters suggested alternative requirements, including
incorporating emissions checks into the pre-shift equipment inspection
required under Sec. 57.14100(a), requiring equipment operators to
either inform their supervisors of any suspected emissions-related
problems or note any suspected emissions-related problems in a log book
provided in every piece of equipment for that purpose, and requiring
the mine operator to insure that a qualified person examines any piece
of equipment for which an emissions-related problem has been
identified.
MSHA has considered these comments, and determined that the
requirements contained in the proposal are both necessary, and more
protective than the alternatives suggested by the commenters. For these
reasons, the requirements contained in the proposal have been retained
without change in the final rule.
MSHA believes that, since equipment operators spend more time
running the equipment than other employees (such as mechanics), and are
present when the equipment functions under the widest range of
operating conditions, they are often better able to detect emissions-
related problems than are mechanics. For this reason, the final rule
requires that equipment operators be authorized and required to affix a
visible and dated tag if they note any evidence that the equipment may
need maintenance in order to comply with the rule's maintenance
requirements. Even though equipment operators may not be trained or
qualified as diesel mechanics, they often know the difference between
normal and abnormal equipment performance, especially as it relates to
diesel particulate matter generation, which is often plainly visible or
apparent (i.e., black smoke while the equipment is under normal load,
rough idling, unusual noises, backfiring, etc.).
MSHA acknowledges that an equipment operator's judgement should not
necessarily be relied upon to remove a piece of diesel equipment from
service, precisely because equipment operators are not specifically
trained or qualified to make such a judgement. Accordingly, the final
rule does not require equipment operators to be granted this authority;
only that they be granted authority to visibly identify a potential
problem machine by affixing a tag. It is then the responsibility of the
mine operator to appropriately respond to the presence of a tag. Note
that the response by the mine operator need not be immediate, nor does
it necessarily require the affected equipment to be removed from
service, as some commenters feared. Mine operators have the authority
to establish work rules and procedures to prevent equipment from

[[Page 5877]]

being removed from service unnecessarily. Equipment operators and
mechanics simply need to be trained as to their respective authority
and responsibility under this section; namely, that equipment operators
need to tag equipment suspected of requiring maintenance attention, and
that qualified mechanics need to follow up to determine if a problem
actually exists, and if so, what corrective maintenance work is needed.
It is highly unlikely that a tag intended to indicate a suspected
emissions-related problems, if properly designed, would be confused
with a tag intended to indicate a safety problem as per
Sec. 57.14100(c). Such tags could be differentiated by size, color, or
other obvious visual characteristics so that mistaking one for the
other would be virtually impossible. As noted below, the final rule
allows mine operators the freedom to develop a design that suits their
circumstances. In contrast, a design mandated by MSHA might be too
similar to a given mine's existing Sec. 57.14100(c) safety tag.
MSHA believes that the equipment tagging requirements of
Sec. 57.14100(c) and Sec. 57.5066(b)(1) are inherently and
significantly different, to the extent that the Sec. 57.14100(c)
requirement, even if modified to include health hazards, could not
achieve the desired effect of Sec. 57.5066(b)(1). The purpose of
Sec. 57.14100(c) is to immediately remove equipment from service if it
poses a safety hazard, whereas the purpose of Sec. 57.5066(b)(1) is to
identify a potential emissions-related problem that might require
maintenance, but does not justify immediate removal from service.
Another important difference is that examinations under
Sec. 57.14100(c) occur before a piece of equipment is placed in
operation on that shift, whereas Sec. 57.5066(b)(1) applies throughout
a work shift. These fundamental differences would make any attempt to
combine the rules overly complicated, which would defeat the
commenter's purpose of simplifying the rule.
As discussed above, MSHA believes that equipment operators should
be authorized and required to note emissions-related deficiencies at
all times during a work shift, and not be limited to making such
observations during a pre-shift equipment inspection or before the
equipment is placed into operation. Some emissions-related problems may
not become apparent until after the equipment has been fully engaged
for some time in heavy duty cycle activities. If the only time
emissions-related deficiencies could be identified is before the
equipment is placed into operation, the mine operator might never learn
about such problems, or the corresponding notification might be
unnecessarily delayed.
MSHA acknowledges that many underground metal and nonmetal mine
operators utilize effective maintenance programs to identify and
correct emissions-related problems in a timely manner. However, MSHA
believes that Secs. 57.5066(b)(1) and (2) are ``best practices'' that
should be implemented at all mines. At mines that already have an
effective program, this provision would serve as a complementary
element. At mines that have no effective program, this provision would
create an important safeguard. Further elaboration on the rationale for
mandating these ``best practices'' was included in the preamble to the
proposal (p. 58119), and a summary was provided in this Part under the
portion of Sec. 57.5060 that discussed ``Meeting the concentration
limit, operator choice of engineering controls.''
The tagging provision of Sec. 57.5066(b) requires judgement on the
parts of both the equipment operator and the MSHA inspector. There is
no absolute standard which precisely defines the physical proof that
constitutes, ``evidence that the equipment may require maintenance in
order to comply with the maintenance standards of paragraph (a) of this
section.'' Thus, MSHA inspectors will be guided by a standard of
reasonableness, based on an equipment operator's ability to
differentiate normal emissions from grossly abnormal emissions. MSHA
does not expect operators to tag equipment whenever there is a minor
aberration or excursion from an optimum or perfect emissions condition,
or that an inspector should make a fine distinction between emissions
that are ``slightly too smoky'' versus ``barely acceptable.'' However,
MSHA inspectors will not ignore an operator's failure to tag a piece of
equipment suffering from a serious emissions-related problem that is so
obvious as to suggest the mine operator is indifferent to, or even
discourages such tagging.
MSHA believes that disgruntled employees' attempts to shut down
equipment by affixing tags indicating possible emissions-related
problems can be effectively controlled and prevented by mine operators
through work rules and procedures, and employee discipline policies.
Mine operators should treat the inappropriate exercise of this
provision by a disgruntled employee no differently than any other
disruptive or malicious behavior. In addition to being preventable,
MSHA believes the inappropriate tagging of equipment would have minimal
impact on mining operations because tagged equipment need not be
immediately removed from service. The maintenance examination that is
triggered by a tag might not take place until the next shift or the
shift after, and if there is truly nothing wrong with the equipment, it
would be obvious to the mechanic performing the examination, and would
therefore only require a few minutes of a mechanic's time.
MSHA considers the provision for tagging equipment to be preferable
to a system which permits equipment operators to simply notify their
supervisor of a suspected emissions-related problem, because the
presence of a tag serves as a caution sign to other miners working on
or near the equipment, as well as a reminder to mine management that
this piece of equipment needs to be examined. Simply informing the
supervisor does not provide this ongoing visual indicator or reminder,
and as miners and equipment are reassigned to different jobs in
different parts of a mine, information that is communicated verbally
can be easily forgotten. A major advantage of tagging is that the tag
goes with the equipment throughout the mine, alerting all who come in
contact with it of the potential dpm emissions problem. In this sense,
tagging requirements are particularly valuable for mobile equipment
that travels from place to place throughout the shift, and may have
multiple operators over the course of several shifts.
Design of the tag. MSHA proposed that the design of the tag be left
to the discretion of the mine operator, with the exception that the tag
must be able to be marked with a date. MSHA sought comment on ``whether
some or all elements of the tag should be standardized to ensure its
purpose is met''.
Several commenters suggested that MSHA should design the tag to be
used for indicating equipment suspected of needing emissions-related
maintenance.
As noted above, the final rule leaves this decision to the
discretion of the mine operator. Since the design of tags required
under Sec. 57.14100(c) is left to the discretion of the operator, it
would be impossible for MSHA to insure that any mandated design for a
tag under Sec. 57.5066(b)(1) would be easily distinguishable from an
existing Sec. 57.14100(c) tag. However, MSHA strongly urges mine
operators to adopt a design for their Sec. 57.5066(b)(1) tags that is
easily distinguishable from the design of their Sec. 57.14100(c) tags,
using, for example, different sizes, colors, or other obvious visual
characteristics.

[[Page 5878]]

Time to inspect equipment. As noted above, MSHA sought specific
comment on whether to define the term ``promptly.'' One commenter
referred to ``promptly examined'' as, ``whatever that is,'' indicating
they believed the term ``promptly examined'' is too vague. Another
commenter suggested that a definite time period for examining equipment
should be specified; namely, ``by the end of the next shift.'' However,
another commenter agreed with MSHA that equipment tagged by an operator
should be, ``promptly examined'' by an authorized diesel maintenance
person. Another commenter proposed that, ``the required examination be
conducted during normally scheduled maintenance cycles.''
The final rule, like the proposal, does not define the term
``promptly''. Operating and maintenance practices vary from mine to
mine to such an extent that a proscriptive requirement mandating a
specific time period within which an examination must be completed may
be infeasibly short for some operators and unnecessarily long for other
operators. However, MSHA's intent is that mine operators will insure
such examinations are performed without undue delay. If a tag is
affixed during a given shift, it would not be unreasonable to complete
that shift before the maintenance examination. If no qualified mechanic
is scheduled to work on the following shift, the equipment could be
operated during that shift as well. However, if a qualified mechanic
was scheduled to work on the next shift, the examination would be
required before the equipment was used.
Tagged Equipment Log. Section 57.5066(b)(3) requires a log to be
retained of all equipment tagged. Moreover, the log must include the
date the equipment is tagged, the date the tagged equipment is
examined, the name of the person making the examination, and the action
taken as a result of the examination. Records in the log about a
particular incident must be retained for at least one year after the
equipment is tagged.
MSHA does not expect the log to be burdensome to the mine operator
or mechanic examining or testing the engine. Based on MSHA's
experience, it is common practice to maintain a log when equipment is
serviced or repaired, consistent with any good maintenance program. The
records of the tagging and servicing, although basic, provide mine
operators, miners and MSHA with a history that will help in determining
whether a maintenance program is being effectively implemented, and
whether emissions-related components on the equipment are being
maintained in a proper and timely fashion.
Several comments addressing the equipment log were received.
Proposed revisions generally retained the requirement for an equipment
log, but varied as to who would maintain the log (equipment operators,
mechanics or supervisors), and how long they should be kept (one year
versus until the condition is examined and remedied). It was also
suggested that all record keeping could be accomplished under
``existing mobile equipment examination standards and maintenance work
order systems,'' and that additional standards were therefore not
needed.
MSHA has concluded that the requirements in the proposal relative
to tagged equipment logs are essential to effectively controlling dpm,
and have therefore been retained in the final rule without change. They
enable both the mine operator and MSHA to track emissions-related
problems on equipment, and the actions taken by the mine operator to
resolve the problems that occur. The logs are also important because
they provide a written record documenting when equipment was tagged,
and how the mine operator responded.
The log creates an accountability chain that clearly indicates the
date the equipment was tagged, the date the tagged equipment was
examined, the name of the person making the examination, and the action
taken as a result of the examination. Without the written record, MSHA
would be unable to ascertain the extent to which mine operators respond
in a timely and appropriate manner to emissions-related problems on
diesel equipment. The one-year record retention requirement is
necessary so that MSHA can review the emissions-related maintenance
history on a given piece of equipment over a meaningful time period.
This will enable MSHA to judge the mine operator's on-going commitment
to proper and timely maintenance of these components. If the log were
kept only until a given maintenance operation was completed, MSHA's
opportunity to assess the mine operator's on-going responsiveness to
emissions-related problems would be limited to the few chance occasions
where a piece of equipment is tagged during an MSHA inspection of the
mine.
These requirements are protective to miners because they force mine
operators to address dpm emissions problems through a systematic and
effective program. The combination of equipment tagging and logging
helps insure problems will be identified and resolved quickly. If
either or both requirements were eliminated, mine operators would be
less likely to receive timely notice of a potential problem, and once
notified, would be less motivated to promptly initiate the required
examination and corrective measures.
Persons qualified to perform maintenance. Section 57.5066(c)
requires that persons who maintain diesel equipment in underground
metal and nonmetal mines be ``qualified,'' by virtue of training or
experience, to ensure the maintenance standards of Sec. 57.5066(a) are
observed. Paragraph (c) also requires that an operator retain
appropriate evidence of ``the competence of any person to perform
specific maintenance tasks'' in compliance with the requirement's
maintenance standards for one year.
The requirements being established in this regard are not as
stringent as those in effect for the maintenance of diesel powered
equipment in underground coal mines. Operators of underground coal
mines where diesel-powered equipment is used are required, as of
November 25, 1997, to establish programs to ensure that persons who
perform maintenance, tests, examinations and repairs on diesel-powered
equipment are qualified (30 CFR 75.1915). The unique conditions in
underground coal mines require the use of specialized equipment.
Accordingly, the persons who maintain this equipment generally must be
appropriately qualified.
If repairs and adjustments to diesel engines used in underground
metal and nonmetal mines are to be done properly, personnel performing
such tasks must be properly trained. MSHA does not believe, however,
that the qualifications required to perform this work in underground
metal and nonmetal mines necessarily require the same level of training
as is required for similar work in underground coal mines. Under the
final rule, the training required would be that which is commensurate
with the maintenance task involved. If examining and, if necessary,
changing a filter or air cleaner is all that is required, a miner who
has been shown how to do these tasks would be qualified by virtue of
training or experience to do those tasks. For more detailed work,
specialized training or additional experience would be required.
Training by a manufacturer's representative, completion of a general
diesel engine maintenance course, or practical experience performing
such repairs could also serve as evidence of having the qualifications
to perform the service.

[[Page 5879]]

In practice, the appropriateness of the training or experience of
the maintenance personnel will be revealed by the performance of the
equipment, both the diesel engine itself and any emission
aftertreatment devices. If MSHA finds a situation where maintenance
appears to be shoddy, where the log indicates an engine has been in for
repair with more frequency than should be required, or where repairs
have damaged engine approval status or emission control effectiveness,
MSHA would ask the operator to provide evidence that the person(s) who
worked on the equipment was properly qualified by virtue of training or
experience.
It is MSHA's intent that equipment sent off-site for maintenance
and repair is also subject to the requirement that the personnel
performing the work be qualified by virtue of training or experience
for the task involved. It is not MSHA's intent that a mine operator
have to examine the training and experience record of off-site
mechanics, but a mine operator will be expected to observe the same
kind of caution as one would observe with a personal vehicle--e.g.,
selecting the proper kind of shop for the nature of the work involved,
and considering prior direct experience with the quality of the shop's
work.
One commenter objected to the requirement that mine operators must
retain evidence of the competence of such workers for one year after
any applicable maintenance task is completed. MSHA believes the
provision is important because the evidence retained by the mine
operator is the only means by which MSHA can judge compliance with the
competency requirement.
Another commenter recommended this provision be dropped from the
final rule because it is unnecessary. This commenter argued that it is
in a mine operator's self interest to employ only qualified diesel
mechanics to perform maintenance on equipment that is critical to the
productive capacity of the mine. Another commenter stated that the rule
is unnecessary because they already keep a file on mechanic training.
MSHA believes this provision is important because not all mine
operators are as careful in employing only qualified persons to
maintain the emissions-related components of their diesel equipment.
For mine operators that do, this requirement should not be burdensome.
For mine operators that don't, this requirement will prevent
unqualified persons from performing improper maintenance procedures on
this equipment, thereby preventing this equipment from generating
potentially excessive diesel emissions.
Another commenter recommended that the final rule should include
minimum qualifications for persons responsible for ventilation at
underground metal and nonmetal mines. The recommendation applied to
mines employing greater than 20 miners, and suggested that the minimum
qualification should be a mining engineering degree from an accredited
university having a program that includes training in the theory and
practice of underground metal and nonmetal mine ventilation, and that
qualified persons should also have some minimum level of operating
experience in this field. MSHA believes that its existing ventilation
regulations and this final dpm rule are appropriately performance
oriented regarding the use of mine ventilation as a dpm control
measure. Mine operators who rely on ventilation will be judged by MSHA
according to their success in complying with the final concentration
limit. Therefore, the final rule has not been changed to require
persons who are responsible for ventilation at mines employing more
than 20 miners to meet any minimum qualifications.

Section 57.5067 Engines

The final rule requires that, with the exception of diesel engines
used in ambulances and fire-fighting equipment, any diesel engines
added to the fleet of an underground metal or nonmetal mine in the
future have to either be engines approved by MSHA under part 7 or part
36 or engines that meet or exceed the applicable dpm emission
requirements of the EPA explicitly incorporated into a table in the
rule. This requirement takes effect 60 days after the date this rule is
promulgated. Only engines approved by MSHA as permissible can be used
in areas of the mine where permissible diesel equipment is required.
The composition of the existing fleet in an underground metal and
nonmetal mine is not impacted by this part of the final rule. However,
after the rule's effective date, any engine introduced into the
underground areas of the mine must be either MSHA approved or meet the
applicable EPA requirements. The term ``introduced'' is explicitly
defined in the final rule to eliminate uncertainty regarding MSHA's
intent. Engines that are introduced means engines in newly purchased
equipment, engines in used equipment brought into the mine, or
replacement engines that have a different serial number than the engine
it is replacing. The term introduced does not include engines that were
previously part of the mine inventory and rebuilt.
The final rule reflects a change from the proposed rule. The
proposed rule would have required that, with the exception of diesel
engines used in ambulances and fire-fighting equipment, any diesel
engines added to the fleet of an underground metal or nonmetal mine in
the future would have to have been approved by MSHA under Part 7 or
Part 36. As discussed below, after reviewing the comments on this
topic, MSHA concluded that it could accomplish the same goal, while
providing operators with considerable extra flexibility, by permitting
engines compliant with applicable EPA standards as an alternative to
MSHA approved engines.
Table Sec. 57.5067-1 in the final rule lists the applicable EPA dpm
standards for diesel engines. The EPA standards represent the dpm
emission limits set by EPA for light duty vehicles, light duty trucks,
heavy duty highway engines, and nonroad engines. MSHA believes that all
engines used in underground M/NM mines would come from these
categories. MSHA chose the current on-highway dpm standards that have
been in effect since 1994 for any commercially available on-highway
vehicle. For nonroad, MSHA mainly used the EPA tier 1 standards that
have been in effect starting in 1996 through 2000.
MSHA did notice one gap in the EPA nonroad standards. For engines
in the 50 to 175 horsepower range, EPA did not list a dpm standard for
tier 1. A tier 2 standard is listed in the final rule table for this
reason. Full EPA implementation of the tier 2 standard for this
horsepower range will become effective in 2003 for engines from 50-100
horsepower and in 2004 for engines 100 to 175 horsepower. However, MSHA
believes that engines in this horsepower range are available now to
meet the standard. MSHA has approved many engines under part 7 in this
horsepower range that would meet the standard, and engine manufacturers
are also producing other engine models in this horsepower range that
meet the standard. The dpm requirement is the same for this engine
horsepower range as was specified for engines in light duty vehicles in
the coal final rule. Therefore, MSHA does not believe that mine
operators will have problems introducing engines that meet any of the
requirements of this section.
Several commenters questioned the need for engine restrictions at
all if the applicable concentration limit could be achieved through
other means. The rationale for this requirement is to promote the
gradual turnover of the

[[Page 5880]]

existing fleet to better, less-polluting engines, thereby reducing dpm
concentrations and attendant health risks. Without this requirement,
there would be no constraint on the introduction of engines that are
inherently higher polluting into underground metal and nonmetal mines.
Such engines, regardless of the level of maintenance they receive,
produce significantly higher dpm emissions than the low polluting
engines mandated in the final rule. MSHA acknowledges that older, high
polluting engines will eventually be replaced with low polluting
engines through the normal equipment turnover process, because EPA
emission requirements (and similar requirements imposed by foreign
regulatory bodies) will make high polluting engines increasingly
difficult for manufacturers to sell for any application. Even if a mine
operator wanted to continue using high polluting engines, such engines
will become more and more scarce over time. But in light of the risks
of dpm exposure to miners, and the history of the underground mining
industry to bring old engines underground and keep them operating for a
long period of time, MSHA has concluded that a rule is required to
bring about the transition to newer engines more quickly than would
otherwise be the case. MSHA considers the gradual introduction of
cleaner engines to be one of the ``best practices'' that is feasible
for all underground metal and nonmetal mines. Further elaboration on
the rationale for mandating these ``best practices'' was included in
the preamble to the proposal (63 FR 58119), and a summary was provided
in this Part under the portion of Sec. 57.5060 that discussed ``Meeting
the concentration limit, operator choice of engineering controls.''
Other commenters recommended that EPA certification be an
acceptable alternative to MSHA approval. As noted above, after
considering the matter, MSHA agrees that engines certified as meeting
applicable EPA standards would provide an acceptable level of
protection to miner health comparable to that which can be achieved by
requiring MSHA approved engines. (For detailed information about the
various ``tiers'' of EPA engine requirements, and the various types of
engine categories, please see Part II, section 5). Therefore, under the
final rule, engines meeting or exceeding applicable particulate
emission requirements of the Environmental Protection Agency (as listed
in the table in Sec. 57.5067(b)) are an acceptable alternative to
engines approved by MSHA as nonpermissible under subpart E of Part 7 of
this title. This change in the final rule will provide mine operators
with a wider choice of acceptable engines, and may reduce compliance
costs.
MSHA is developing a program that will streamline the procedures by
which manufacturers of diesel engines intended for use in outby areas
of underground coal mines can gain Agency approval. The program will
draw on the EPA approval programs for engines used in off-road
applications. MSHA will continue to issue approvals for mining engines,
but the application process will be abbreviated. Many of the provisions
of part 7 are intended to ensure that engines continue to be
manufactured in the same configuration and with the same emissions as
the engine tested by MSHA. Procedures within the EPA approval programs
reach the same end. Additionally, EPA has the resources and the
regulatory authority to conduct an extensive quality assurance program
to monitor emissions from production engines. In addition to
streamlining the application process, MSHA will establish a program
under which the engine emission tests conducted for EPA approval will
satisfy the part 7 testing requirements. The test cycles under which
emissions are tested for both MSHA and EPA are identical, and the
gaseous emission results from the EPA tests can be used to establish
the ventilating air quantity that appears on the engine approval plate
and is referenced in mine ventilation regulations. MSHA will announce
the specifics of the program when it is finalized. A listing of MSHA
approved nonpermissible engines has been provided on MSHA's Internet
web site. This listing can be accessed at the following address: http:/
/www.msha.gov/S&HINFO/DESLREG/1909a.HTM.
Many underground metal and nonmetal mines are accustomed to
employing front end loaders, haulage trucks, and other production
equipment that is developed for, and primarily marketed to the surface
mining and construction industries. Likewise, where conditions permit,
underground metal and nonmetal mines often employ support vehicles such
as pickup trucks, sport utility vehicles, and other small to medium
sized trucks that are developed for, and primarily marketed to the
surface over-the-road market. Mine operators employ this equipment
because it is significantly less costly than purpose-built underground
mining equipment, which has special mine-duty features and is produced
in relatively low volume.
The engines in newly manufactured surface off-road equipment and
over-the-road vehicles are already required to comply with EPA dpm
emission regulations. EPA regulations are fashioned in a Tier structure
whereby engines in designated horsepower ranges are required to meet
increasingly stringent emissions levels. By changing the final rule as
indicated above to accept engines meeting or exceeding applicable
particulate emission requirements of the EPA, MSHA is, in essence,
allowing mine operators to continue the long-standing and cost-
effective practice of employing standard off-road equipment and over-
the-road vehicles underground (if they are equipped with engines
meeting the appropriate EPA requirements), without requiring
potentially costly retrofits of approved engines. This change will
enable mine operators and mine workers to gain the added benefits of
engines that incorporate the most recent emission reducing technology.
Laboratory testing to certify that an engine meets the applicable
EPA particulate matter limit or MSHA approval requirements is not the
responsibility of the mine operator. MSHA approved engines carry an
approval plate so they are easy to distinguish. Engines produced after
the date indicated in the Table incorporated into 5067(b) will meet the
EPA requirements for the listed category of engines.
Engines in diesel-powered ambulances and fire-fighting equipment
are exempted from these requirements. This exemption is identical with
that in the rule for diesel-powered equipment in underground coal
mines. The rationale for this exemption is that the usage of these
vehicles and equipment is so limited that their contribution to overall
dpm levels in a mine is negligible. MSHA wishes to caution mine
operators, however, that this exemption is intended to apply only to
equipment that is used exclusively as an ambulance or fire fighting
equipment. This exemption does not apply to vehicles and equipment that
are normally used for other purposes, but serve as an ambulance or fire
fighting equipment in the event of an accident or mine emergency.

Section 57.5070 Miner Training

Section 57.5070 requires any miner ``who can reasonably be expected
to be exposed to diesel emissions'' be trained annually in: (a) The
health risks associated with dpm exposure; (b) the methods used in the
mine to control dpm concentrations; (c) identification of the personnel
responsible for

[[Page 5881]]

maintaining those controls; and (d) actions miners must take to ensure
the controls operate as intended. The final rule is the same as that
proposed, and is identical to the rule being established for
underground coal miners through MSHA's rulemaking limiting dpm
concentrations in underground coal mines.
The purpose of these requirements is to promote miner awareness.
Exposure to diesel particulate is associated with a number of harmful
effects as discussed in Part III of this preamble, and the safe level
is unknown. Miners who work in mines where they are exposed to this
risk ought to be reminded of the hazard often enough to make them
active and committed partners in implementing actions that will reduce
that risk.
The training need only be provided to miners who can reasonably be
expected to be exposed at the mine. The training is to be provided by
operators; hence, it is to be without fee to the miner.
The rule places no constraints on the operator as to how to
accomplish this training. MSHA believes that the required training can
be provided at minimal cost and minimal disruption. The proposal would
not require any special qualifications for instructors, nor would it
specify the hours of instruction.
Instruction could take place at safety meetings before the shift
begins. Devoting one of those meetings to the topic of dpm would be a
very easy way to convey the necessary information. Simply providing
miners with a copy of MSHA's ``Toolbox'' and, a copy of the plan, if a
control plan is in effect for the mine, and reviewing these documents,
can cover several of the training requirements. One-on-one discussions
that cover the required topics are another approach that can be used.
Operators could also choose to include a discussion on diesel
particulate matter emissions in their Part 48 training, provided the
plan is approved by MSHA. There is no existing requirement that Part 48
training include a discussion of the hazards and control of diesel
emissions. While mine operators are free to cover additional topics
during the Part 48 training sessions, the topics that must be covered
during the required time frame may make it impracticable to cover the
additional material on dpm. Where adequate time is available at mines
using diesel-powered equipment, operators would be free to include the
dpm instruction in their Part 48 training plans. Since inclusion of
dpm-related training in Part 48 training plans is not explicitly
prohibited in the final rule, MSHA does not believe special language is
required to permit this practice.
The final rule does not require the mine operator to separately
certify the completion of the dpm training, but some evidence that the
training took place would have to be produced upon request. A serial
log with the employee's signature is an acceptable practice. To assist
mine operators with this training requirement, it is MSHA's intent to
develop an instructor's guide and corresponding training materials.
A few comments were received on Sec. 57.5070, including the
suggestion that such training be included under Part 48, and the
opposing view that such training be independent of Part 48. Arguments
in favor of including the training under Part 48 focused on the need to
simplify the rule by not requiring separate diesel particulate
emissions training and training recordkeeping. Arguments opposed
focused on the difficulty of including more subject matter into a Part
48 training plan that is already overfilled. It was also noted that
Part 48 training requires MSHA-certified instructors. By separating
Part 48 training from the training required under Sec. 57.5070, mine
operators would have greater flexibility in choosing instructors.
MSHA believes the final rule satisfies both positions because
inclusion of the specified diesel particulate emissions training topics
under Part 48 training is neither required nor prohibited. Mine
operators wishing to incorporate diesel emissions training in their
Part 48 training plan are free to do so, whereas those wishing to
conduct diesel emissions training separate from Part 48 training are
equally free to choose that option. MSHA believes it is significant
that none of the commenters discounted the importance of providing dpm-
exposed miners with such training; their comments only addressed the
mechanics of how such training should be delivered.
In its preamble to the proposed rule, MSHA specifically invited
comment as to whether special language should be included in the final
rule that would expressly permit required dpm training to be
incorporated into Part 48 training. Only one commenter responded,
expressing the view that special language was not necessary. Therefore,
MSHA did not change this provision in the final rule.
Another commenter suggested that training required under
Sec. 57.5070 incorporate mandatory coverage of underground metal and
nonmetal mine ventilation, that such training address auxiliary
ventilation and the use of elementary ventilation measurement
instruments, and that similar training be mandatory for first and
second line supervisors.
MSHA agrees that ventilation is an important topic and that
ventilation can have a significant effect on dpm concentrations
underground. However, MSHA believes it would be inappropriate to
specify the content of dpm-related miner training to the level of
detail suggested by the commenter. Since MSHA allows mine operators
considerable freedom to choose dpm control measures, MSHA expects
significant variability from mine to mine in the mix of controls
selected. For example, some mines may rely heavily on ventilation to
comply with the applicable concentration limit, but other mines may
rely more on enclosed cabs or diesel particulate filters. As a result,
the most important training subject or subjects at one mine could be
quite different at another mine.
By requiring training in the health risks associated with dpm
exposure, the methods used in the mine to control dpm concentrations,
identification of the personnel responsible for maintaining those
controls, and the actions miners must take to ensure the controls
operate as intended, MSHA believes it has established performance-based
training requirements that are applicable to all mines.
As with the proposed rule, the final rule does not require the mine
operator to separately certify the completion of dpm training, but some
evidence that the training took place will have to be produced upon
MSHA request. In this regard, as noted in the preamble to the proposed
rule, a serial log with the employee's signature is an acceptable
practice. Nevertheless, some commenters complained that the
recordkeeping requirements in the training provisions are burdensome,
and don't reduce diesel emissions. MSHA believes that dpm training is
an essential element of a comprehensive dpm control program because
miners who are fully informed are more apt to become active and
committed partners in implementing an effective dpm control strategy.
In this way, training can have an indirect, yet substantive and
positive influence on reducing dpm exposure. The corresponding
recordkeeping requirements are important, because the records are the
means by which MSHA can insure that the mine operator is complying with
the training requirements.
As noted in the preamble to the proposed rule, to assist mine
operators with this training requirement, it is MSHA's intent to
develop an instruction outline that mine operators can use as

[[Page 5882]]

a guide for training personnel. Instruction materials will be provided
with the outline.

Section 57.5071 Environmental Monitoring

The final rule requires mine operators to monitor as often as
necessary to effectively evaluate, under conditions that can be
reasonably anticipated in the mine--(1) whether the concentration of
dpm in an area where miners normally work or travel exceeds the
applicable concentration limit; and (2) the average full shift airborne
concentration at any position or on any person designated by the
Secretary. This section also requires operators to provide affected
miners and their representatives with notice and an opportunity to
observe monitoring, to initiate corrective action by the next work
shift should monitoring reveal a violation and to promptly complete
such action, and requires certain posting and recordkeeping. The final
rule is the same as the proposed rule.
Operator's Monitoring Responsibility. Section 57.5071(a) requires
mine operators to monitor the underground mine environment to insure
dpm concentrations are within compliance limits wherever the limits
apply. Sampling, which could be area sampling, personal sampling, or
occupational sampling, is required as often as necessary to
``effectively determine''--under conditions that can be reasonably
anticipated in the mine--(1) whether the dpm concentration in any area
of the mine where miners normally work or travel exceeds the applicable
limit; and (2) the average full shift airborne concentration at any
position or on any person designated by the Secretary.
This requirement is similar to existing Sec. 57.5002 which requires
mine operators to conduct dust, gas, mist, and fume surveys as
frequently as necessary to determine the adequacy of control measures,
and to existing Sec. 62.110(a) and (b) which requires mine operators to
measure each miner's noise dose sufficient to determine continuing
compliance with the established noise limits. Under Sec. 57.5071(a),
mine operators are required to monitor dpm concentrations in much the
same way they are already required to monitor dust, gas, mist, fume,
and noise.
There are three important aspects of this operator monitoring
requirement.
First, the responsibility for dpm monitoring rests with the mine
operator, not with MSHA. Mine operators cannot rely on MSHA inspectors
to conduct dpm monitoring whenever and wherever necessary to ensure
compliance with the applicable dpm concentration limit. The purpose of
operator monitoring is to determine continuing compliance, whereas the
purpose of MSHA sampling is to identify non-compliance. MSHA sampling
is neither intended for, nor capable of determining continued
compliance.
Second, the information gathered through operator monitoring is to
be used by the operator to determine whether action is necessary to
maintain compliance anywhere the applicable concentration limits apply
in the mine. Gathering dpm concentration data, though necessary, is not
the final goal in itself. The reason for gathering this information is
so it can be used by the mine operator to assess the effectiveness of
dpm control measures. Sampling results which indicate non-compliance
should prompt the mine operator to initiate whatever actions are
required (i.e., implementation of appropriate engineering controls and
work practices) to achieve compliance wherever the applicable
concentration limits apply.
Third, this requirement ensures special attention will be focused
on locations or persons known to MSHA to have a significant potential
for overexposure to dpm.
The obligation of operators to ``effectively determine'' dpm
concentrations in a mine is a separate obligation from that to keep dpm
levels below the established limit, and can be the basis of a separate
citation from MSHA. The final rule is performance-oriented in that the
regularity and methodology used to make this evaluation are not
specified. However, MSHA expects mine operators to sample with such
frequency that they and the miners working at the mine site are aware
of dpm levels in their work environment. In this regard, MSHA's own
measurements will assist the Agency in verifying the effectiveness of
an operator's monitoring program. If an operator is ``effectively
determining'' the concentration of dpm at designated positions, for
example, MSHA would not expect to regularly record concentrations above
the limit when it samples at that location. If MSHA does find such a
problem, it will investigate to determine how frequently an operator is
sampling, where the operator is sampling, and what methodology is being
used, so as to determine whether the obligation in this section is
being fulfilled. (See previous discussion in this Part in the portion
of Sec. 57.5062 that addressed ``Demonstration of plan effectiveness''
for further information on the number of samples required to
demonstrate continuing compliance.)
Operator Monitoring Methods. The final rule requires that full-
shift diesel particulate concentrations be determined during periods of
normal production or normal work activity in areas where miners work or
travel. The rule does not specify a particular monitoring method or
frequency; rather, the rule is performance-oriented. Operators may, at
their discretion, conduct their monitoring using the same sampling and
analytical method as MSHA, or they may use any other method that
enables that mine to ``effectively determine'' the concentrations of
dpm.
As required by Sec. 57.5061, MSHA will collect samples using a
respirable dust sampler equipped with a submicrometer impactor, and use
NIOSH Method 5040, the sampling and analytical method that NIOSH has
developed for accurately determining the concentration of total carbon,
to determine compliance. Operators who must comply with the terms of a
diesel particulate control plan pursuant to Sec. 57.5062 must, as noted
in the requirements of that section, use the same sampling and
analytical method as MSHA to verify plan effectiveness; monitoring
performed for that purpose would probably meet the obligation under
Sec. 5071 if it is done with enough sufficiency to meet the obligation
under Sec. 57.5062(c). But the method may not be necessary to
effectively determine dpm in some mines for purposes of
Sec. 57.5071(a). For example, dpm measurements in limestone, potash and
salt mines could be determined using the RCD method, since there are no
large carbonaceous particles present that would interfere with the
analysis. For hydrated minerals such as gypsum and trona, a two-step
RCD method would be necessary, wherein the first step would elevate the
temperature of the sample sufficient to cause dehydration (105 deg.C).
The sample is then reweighed, and the conventional RCD analysis
procedure is followed. Such estimates can be useful in determining the
effectiveness of controls and where more refined measurements may be
required.
Of course, mine operators using the RCD or size-selective methods
to monitor their diesel particulate concentrations would have to
convert the results to a TC equivalent to ascertain their compliance
status. At the present time, MSHA has no conversion tables for this
purpose, however a simple conversion approach would be to adjust the
sampling result to the corresponding estimated whole dpm concentration,
then multiply that value by 0.8. In most cases, the other methods will
provide a good indication of

[[Page 5883]]

whether controls are working and whether further action is required.
Part II of this preamble provides information on monitoring methods
and their constraints, and on laboratory and sampler availability.
One commenter observed that area sampling outside of an enclosed
cab would defeat the purpose of installing the cab, and would diminish
the status of such a cab, which is a recognized engineering control, to
that of personal protective equipment, which is prohibited under the
rule. MSHA agrees that area sampling is inappropriate where miners are
protected by enclosed cabs with filtered breathing air and no other
miners are required to work in the area outside of the cab. As
discussed under section 5061(c)(3), area sampling by MSHA for
compliance purposes would not be conducted outside of an enclosed cab
unless miners are working in the area outside of such cabs, and MSHA
would urge operators to follow the same approach. Also, as noted in
discussing that section, personal sampling within cabs operated by
smokers should only be conducted if the equipment operator agrees not
to smoke during the sampling period.
Observation of Monitoring. Section 103(c) of the Mine Act requires
that:

The Secretary, in cooperation with the Secretary of Health,
Education, and Welfare, shall issue regulations requiring operators
to maintain accurate records of employee exposures to potentially
toxic materials or harmful physical agents which are required to be
monitored or measured under any applicable mandatory health or
safety standard promulgated under this Act. Such regulations shall
provide miners or their representatives with an opportunity to
observe such monitoring or measuring, and to have access to the
records thereof.

In accordance with this legal requirement, Sec. 57.5071(b) of the
final rule requires a mine operator to provide affected miners and
their representatives with an opportunity to observe exposure
monitoring required by this section. Mine operators must give prior
notice of the date and time of intended monitoring so that affected
miners and their representatives can exercise their right to observe
the monitoring if they so choose.
Comments addressing Sec. 57.5071(b) questioned the meaning of the
terms ``miner's representative'' and ``affected miners,'' and objected
to paying miners to observe dpm monitoring.
MSHA intends for miner's representative to mean any authorized
representative of the miners. A representative of the miners could, but
does not necessarily have to be, a representative of a certified union.
Limiting representatives of miners to certified unions is a violation
of the Mine Act and departs from previous MSHA practice.
MSHA intends for affected miners to mean the miners that are
potentially exposed to the diesel particulate matter being monitored.
The commenter suggested that this provision ``* * * leaves too much for
interpretation. How many employees may observe? For how long?''
Consistent with the Mine Act, MSHA does not intend to limit the number
of miners who may observe dpm monitoring, however, such miners need not
be paid if, as a result of observing the monitoring, they are not
performing their jobs.
Corrective Action if Concentration Is Exceeded. Section 57.5071(c)
provides that if any monitoring performed under this section indicates
that the applicable dpm concentration limit has been exceeded, an
operator shall initiate corrective action by the next work shift,
promptly post a notice of the corrective action being taken and
promptly complete such corrective action.
The Agency wishes to emphasize that operator monitoring of dpm
concentrations would not take the place of MSHA sampling for compliance
purposes; rather, this requirement is designed to ensure the operator
checks dpm concentrations on a more regular basis than is possible for
MSHA to do. Paragraph (c) provides that if sampling results indicate
the concentration limit has been exceeded in an area of a mine, an
operator would initiate corrective action by the next work shift and
promptly complete such action. Paragraph (c) does not require an
operator to establish a dpm control plan. The establishment of a dpm
control plan is triggered by a non-compliance determination based on
sampling conducted by the Secretary.
In certain types of cases (e.g., 30 CFR 75.323), MSHA has required
that when monitoring detects a hazardous level of a substance, miners
must be immediately withdrawn from an area until abatement action has
been completed. Although MSHA did not include such a requirement in the
final rule, MSHA in its proposal did solicit comment from the mining
industry concerning this practice, especially in light of the evidence
presented on the various risks posed by exposure to diesel particulate,
including material presented in the preamble to the proposal that acute
short-term increases in exposure can pose significant risks to miner
health. The comments that were received in response to this
solicitation were opposed to a provision requiring immediate
withdrawal.
The agency also specifically asked for comments on three other
points (63 FR 58189, 58190). First, the agency noted that it welcomed
comments as to what guidance to provide with respect to corrective
actions required where an operator is not using the total carbon
analytical method. Second, the agency noted it welcomed comment as to
whether personal notice of corrective action would be more appropriate
than posting, given the health risks involved. Third, the agency
solicited comment on whether clarification of the proposed requirement
was needed in light of the fact that operators using more complex
analytical procedures (e.g., the total carbon method) may not receive
the results for some time period after the posting has taken place.
No comments addressing these points were received.
Posting of Sample Results. Section 57.5071(d)(1) requires that
monitoring results be posted on the mine bulletin board within 15 days
of receipt, and remain posted for 30 days. A copy of the results must
also be provided to the authorized miners' representative. Posting of
the results will ensure that miners are kept aware of the hazard so
they can actively participate in efforts to control dpm.
Comments that addressed this paragraph recommended that sampling
results should not be given to the representative of the miners because
this information is private, and recommended that mine operators should
not be cited for posting sampling results that exceed the applicable
concentration limit.
MSHA disagrees with the assertion that dpm sampling results are
private, and therefore, such results should not be given the
representative of the miners. The Mine Act clearly states that miners
or their representatives have a legal right to access to exposure
monitoring information.
Regarding the question of MSHA issuing a citation based on a mine
operator posting sampling results that exceed the applicable
concentration limit, it is not MSHA's intent to issue a citation under
these circumstances. If such sampling indicates that dpm levels exceed
the applicable concentration limit, a citation may be issued if the
mine operator fails to initiate corrective action by the next work
shift, as required under Sec. 57.5071(c). However, mine operator
sampling results that exceed the applicable limit is not, by itself, a
violation.
MSHA recognizes that this is an important point, and reiterates
that, as indicated in Sec. 57.5061, MSHA itself is to conduct
compliance sampling.

[[Page 5884]]

Retention of Sample Results. Section 57.5071(d)(2) requires that
records of the sampling method and the sample results themselves be
retained by mine operators for five years. This is because the results
from a monitoring program can provide insight as to the effectiveness
of controls over time, and provide a history of occupational exposures
at the mine.
In the preamble to the proposed rule, MSHA welcomed comments on the
sample retention period appropriate for the risks involved. None were
received.
In the preamble to the proposed rule, MSHA also asked for comments
regarding the advisability of instituting a system of medical
surveillance of miners exposed to dpm to identify miners suffering ill
effects of dpm exposure, and the subsequent medical removal of miners
who are determined to be suffering such ill effects. The comments
received in response to this request suggested that medical
surveillance for excessive dpm exposure is not feasible at this time
because the appropriate biological tests or markers do not exist. One
commenter observed that they were, ``* * * unaware of any recognized or
generally accepted examinations or tests for detecting whether miners
are suffering from ill effects as a result of diesel particulate or
exhaust exposure. This view is supported by EPA's Health Assessment
Document for Diesel Emissions which states, `There is no single medical
test to determine if DP exposure has occurred. Many symptoms of
episodic DP exposure are similar to symptoms caused by other agents or,
in some cases, onset of a common cold. Invasive sampling of particle
deposits in the upper respiratory tract or lung could be done, yet such
particles may not be readily distinguishable from particulate matter
from other sources' [EPA, 1998].'' MSHA agrees with these commenters
that appropriate medical testing protocols are not currently available.
Therefore, provision for neither medical surveillance nor medical
removal protections have been incorporated into the final rule.

Section 57.5075 Diesel Particulate Records

Various recordkeeping requirements are set forth in the provisions
of the final rule. For the convenience of the mining community, these
requirements are also listed in a table entitled ``Diesel Particulate
Recordkeeping Requirements,'' which can be found in Sec. 57.5075(a).
Each row involves a record that must be kept. The section requiring the
record be kept is noted, along with the retention time.
This approach--having a summary table of recordkeeping requirements
included in various sections of the rule--is identical to that taken in
the proposed rule. MSHA indicated in the preamble to the proposed rule
that it would welcome input from the mining community as to whether it
liked this approach or found it duplicative or confusing, however, no
comments were received.
Location of Records. Section 57.5075(b)(1) provides that any record
which is required to be retained at the mine site may be retained
elsewhere if it is immediately accessible from the mine site by
electronic transmission. Compliance records need to be accessible to an
inspector so they can be viewed during the course of an inspection, as
the information in the records may determine how the inspection
proceeds. If the mine site has a fax machine or computer terminal,
there is no reason why the records cannot be maintained elsewhere.
MSHA's approach in this regard is consistent with Office of Management
and Budget Circular A-130.
One commenter, though supporting the concept of off-site electronic
records storage, questioned MSHA's intent relative to the term
``immediately accessible.'' As noted above, MSHA intends that records
maintained off-site be made available to an MSHA inspector so the
information can be used to guide inspection decisions. Thus, undue
delay in retrieving this information from off site electronic storage
would impede an inspection, and would not be permitted. If the records
are maintained in hardcopy form at an off-site location, and
considering the time required to contact off-site personnel to request
the records, for those personnel to locate and remove the records from
the files, and to fax the records to the mine site, a delay of one or
two hours would not be unreasonable. If records are maintained in an
off-site electronic database, it is reasonable to assume they could be
electronically transmitted to the mine site even faster; perhaps one
hour or less.
These time frames are in contrast to the requirement in MSHA's new
noise regulation for noise records to be accessible to the MSHA
inspector, but not ``immediately accessible.'' The guideline
established in the Preamble to the final noise rule states that records
must be provided to the MSHA inspector within one business day or less
(p. 49625).
The commenter notes further that, ``Even with Y2K compliant
systems, computer and electronic transmission equipment is not 100%
reliable, especially in remote mining environments.'' MSHA agrees that
an insistence on 100% reliability of computer and electronic
transmission equipment is unreasonable. However, MSHA will not accept
chronic computer or electronic transmission problems as a justification
for the repeated denial of timely access to the required records. If
chronic computer or electronic transmission problems make ``immediate''
access to records problematic, such records would have to be kept at
the mine site.
Records Access. Section 57.5075(b) also covers records access.
Consistent with the statute, upon request from an authorized
representative of the Secretary of Labor, the Secretary of Health and
Human Services, or from the authorized representative of miners, mine
operators are to promptly provide access to any record listed in the
table in this section. A miner, former miner, or, with the miner's or
former miner's written consent, a personal representative of a miner,
is to have access to any exposure record required to be maintained
pursuant to Sec. 57.5071 to the extent the information pertains to the
miner or former miner. Upon request, the operator must provide the
first copy of such record at no cost. Whenever an operator ceases to do
business, that operator would be required to transfer all records
required to be maintained by this part to any successor operator.
General Effective Date of Part 57. The rule provides that unless
otherwise specified, its provisions take effect 60 days after the date
of promulgation of the final rule. Thus, for example, the requirements
to implement certain work practice controls (e.g., fuel type) go into
effect 60 days after the final rule is published.
A number of provisions of the final rule contain separate effective
dates that provide more time for technical support. For example, the
initial concentration limit for underground metal and nonmetal mines
would be delayed for 18 months.
A general outline of effective dates is summarized in Part I of
this preamble.
Additionally, the paperwork provisions will not become effective
until approved by the Office of Management and Budget.

V. Adequacy of Protection and Feasibility of Final Rule;
Alternatives Considered

The Mine Act requires that in promulgating a standard, the
Secretary, based on the best available evidence, shall attain the
highest degree of health

[[Page 5885]]

and safety protection for the miner with feasibility a consideration.
Overview. This part begins with a summary of the pertinent legal
requirements, followed by a general profile of the economic health and
prospects of the metal and nonmetal mining industry.
The final rule establishes a concentration limit for dpm,
supplemented by monitoring and training requirements. An operator in
the metal and nonmetal sector would have the flexibility to choose any
type or combination of engineering controls to keep dpm levels at or
below the concentration limit. This part evaluates the final rule to
ascertain if, as required by the statute, it achieves the highest
degree of protection for underground metal and nonmetal miners that is
feasible, both technologically and economically, for underground metal
and nonmetal mine operators to provide.
Several regulatory alternatives to the final rule were also
reviewed by MSHA in light of the record. The Agency has concluded that
compliance with these alternatives either provide less protection than
the feasible approach being adopted, or are not technologically or
economically feasible for the underground metal and nonmetal industry
as a whole at this time.
Pertinent Legal Requirements. Section 101(a)(6)(A) of the Federal
Mine Safety and Health Act of 1977 (Mine Act) states that MSHA's
promulgation of health standards must:

* * * [A]dequately assure, on the basis of the best available
evidence, that no miner will suffer material impairment of health or
functional capacity even if such miner has regular exposure to the
hazards dealt with by such standard for the period of his working
life.

The Mine Act also specifies that the Secretary of Labor
(Secretary), in promulgating mandatory standards pertaining to toxic
materials or harmful physical agents, base such standards upon:

* * * [R]esearch, demonstrations, experiments, and such other
information as may be appropriate. In addition to the attainment of
the highest degree of health and safety protection for the miner,
other considerations shall be the latest available scientific data
in the field, the feasibility of the standards, and experience
gained under this and other health and safety laws. Whenever
practicable, the mandatory health or safety standard promulgated
shall be expressed in terms of objective criteria and of the
performance desired. [Section 101(a)(6)(A)].

Thus, the Mine Act requires that the Secretary, in promulgating a
standard, based on the best available evidence, attain the highest
degree of health and safety protection for the miner with feasibility a
consideration.
In relation to feasibility, the legislative history of the Mine Act
states that:

* * *Section further provides that ``other considerations'' in
the setting of health standards are ``the latest available
scientific data in the field, the feasibility of the standards, and
experience gained under this and other health and safety laws.''
While feasibility of the standard may be taken into consideration
with respect to engineering controls, this factor should have a
substantially less significant role. Thus, the Secretary may
appropriately consider the state of the engineering art in industry
at the time the standard is promulgated. However, as the circuit
courts of appeal have recognized, occupational safety and health
statutes should be viewed as ``technology-forcing'' legislation, and
a proposed health standard should not be rejected as infeasible when
the necessary technology looms in today's horizon. AFL-CIO v.
Brennan, 530 F.2d 109 (1975); Society of the Plastics Industry v.
OSHA, 509 F.2d 1301, cert. denied, 427 U.S. 992 (1975).

Similarly, information on the economic impact of a health standard
which is provided to the Secretary of Labor at a hearing or during the
public comment period, may be given weight by the Secretary. In
adopting the language of [this section], the Committee wishes to
emphasize that it rejects the view that cost benefit ratios alone may
be the basis for depriving miners of the health protection which the
law was intended to insure. S. Rep. No. 95-181, 95th Cong., 1st Sess.
21 (1977).
Court decisions have clarified the meaning of feasibility. The
Supreme Court, in American Textile Manufacturers' Institute v. Donovan
(OSHA Cotton Dust), 452 U.S. 490, 101 S.Ct. 2478 (1981), defined the
word ``feasible'' as ``capable of being done, executed, or effected.''
The Court stated that a standard would not be considered economically
feasible if an entire industry's competitive structure was threatened.
According to the Court, the appropriate inquiry into a standard's
economic feasibility is whether the standard is capable of being
achieved.
Courts do not expect hard and precise predictions from agencies
regarding feasibility. Congress intended for the ``arbitrary and
capricious standard'' to be applied in judicial review of MSHA
rulemaking (S.Rep. No. 95-181, at 21.) Under this standard, MSHA need
only base its predictions on reasonable inferences drawn from the
existing facts. MSHA is required to produce reasonable assessment of
the likely range of costs that a new standard will have on an industry.
The agency must also show that a reasonable probability exists that the
typical firm in an industry will be able to develop and install
controls that will meet the standard. See, Citizens to Preserve Overton
Park v. Volpe, 401 U.S. 402, 91 S.Ct. 814 (1971); Baltimore Gas &
Electric Co. v. NRDC, 462 U.S. 87 103 S.Ct. 2246, (1983); Motor Vehicle
Manufacturers Assn. v. State Farm Mutual Automobile Insurance Co., 463
U.S. 29, 103 S.Ct. 2856 (1983); International Ladies' Garment Workers'
Union v. Donovan, 722 F.2d 795, 232 U.S. App. D.C. 309 (1983), cert.
denied, 469 U.S. 820 (1984); Bowen v. American Hospital Assn., 476 U.S.
610, 106 S.Ct. 2101 (1986).
In developing a health standard, MSHA must also show that modern
technology has at least conceived some industrial strategies or devices
that are likely to be capable of meeting the standard, and which
industry is generally capable of adopting. United Steelworkers of
America v. Marshall, 647 F.2d 1189, 1272 (1980). If only the most
technologically advanced companies in an industry are capable of
meeting the standard, then that would be sufficient demonstration of
feasibility (this would be true even if only some of the operations met
the standard for some of the time). American Iron and Steel Institute
v. OSHA, 577 F.2d 825, (3d Cir. 1978); see also, Industrial Union
Department, AFL-CIO v. Hodgson, 499 F.2d 467 (1974).
Industry Profile. This industry profile provides background
information about the structure and economic characteristics of the
mining industry. It provides data on the number of mines, their size,
the number of employees, and the diesel powered equipment used.
The Structure of the Metal/Nonmetal Mining Industry. MSHA divides
the mining industry into two major segments based on commodity: (1)
Coal mines and (2) metal and nonmetal (M/NM) mines. These segments are
further divided based on type of operation (e.g., underground mines or
surface mines). MSHA maintains its own data on mine type, size, and
employment, and the Agency also collects data on the number of
independent contractors and contractor employees by major industry
segment.
MSHA categorizes mines by size based on employment. For the past 20
years, for rulemaking purposes, MSHA has consistently defined a small
mine to be one that employs fewer than 20 workers and a large mine to
be one that employs 20 or more workers. To comply with the requirements
of the Small

[[Page 5886]]

Business Regulatory Enforcement Fairness Act (SBREFA) amendments to the
Regulatory Flexibility Act (RFA), however, an agency must use the Small
Business Administration's (SBA's) criteria for a small entity-\3/4\ for
mining, 500 or fewer employees \3/4\ when determining a rule's economic
impact.
Table V-1 presents the total number of small and large mines and
the corresponding number of miners, excluding contractors, for the M/NM
mining segment. The M/NM mining segment consists of metal mines
(copper, iron ore, gold, silver, etc.) and nonmetal mines (stone
including granite, limestone, dolomite, sandstone, slate, and marble;
sand and gravel; and others such as clays, potash, soda ash, salt,
talc, and pyrophyllite.) As Table II-1 indicates, 98 percent of all M/
NM mines are surface mines, and these mines employ some 90 percent of
all M/NM miners, excluding office workers. Table V-2 presents
corresponding data on the number of independent contractors and their
employees working in the M/NM mining segment.

Table V-1.--Distribution of M/NM Mine Operations and Employment (Excluding Contractors) by Mine Type and Size
\a\
----------------------------------------------------------------------------------------------------------------
Mine type
---------------------------------------------------
Size of M/NM mine \b\ Office
Underground Surface workers Total M/NM
----------------------------------------------------------------------------------------------------------------
Fewer than 20 employees:
Mines................................................... 134 9,635 ........... 9,769
Employees............................................... 1,054 54,356 9,160 64,570
20 to 500 employees:
Mines................................................... 124 1,419 ........... 1,543
Employees............................................... 11,299 79,675 15,040 106,014
Over 500 employees:
Mines................................................... 7 18 ........... 25
Employees............................................... 4,594 16,836 3,543 24,973
All M/NM mines:
Mines................................................... 265 11,072 ........... 11,337
Employees............................................... 16,947 150,867 27,743 195,557
----------------------------------------------------------------------------------------------------------------
\a\ Source: U.S. Department of Labor, Mine Safety and Health Administration, Office of Standards, Regulations,
and Variances based on 1998 MS data, CM441/CM935LA cycle 1998/198. Data for Total Office workers from Mine
Injury and Worktime Quarterly (1997 Closeout Edition) Table 2, p. 6.
\b\ Based on MSHA's traditional definition, large mines include all mines with 20 or more employees. Based on
SBA's definition, as required by SBREFA, large mines include only mines with over 500 employees.

Table V-2.--Distribution of M/NM Contractors and Contractor Employment by Size of Operation \a\
----------------------------------------------------------------------------------------------------------------
Contractors
---------------------------------------------------
Size of contractors \b\ Office
Underground Surface workers Total
----------------------------------------------------------------------------------------------------------------
Fewer than 20 employees:
Mines................................................... 399 2,783 ........... 3,182
Employees............................................... 1,717 14,155 649 16,521
20 to 500 employees:
Mines................................................... 36 349 ........... 384
Employees............................................... 1,639 17,979 802 20,420
Over 500 employees:
Mines................................................... ........... 3 ........... 3
Employees............................................... ........... 2,560 105 2,665
Total contractors:
Mines............................................... 434 3,135 ........... 3,569
Employees........................................... 3,356 34,694 1,556 39,606
----------------------------------------------------------------------------------------------------------------
\a\ Source: U.S. Department of Labor, Mine Safety and Health Administration, Office of Standards, Regulations,
and Variances based on 1998 MS data, CT441/CT935LA cycle 1998/198. Data for total office workers from Mine
Injury and Worktime Quarterly (1998 Closeout Edition) Table 6, p. 21.
\b\ Based on MSHA's traditional definition, large mines include all mines with 20 or more employees. Based on
SBA's definition, as required by SBREFA, large mines include only mines with over 500 employees.

The M/NM mining sector consists of about 80 different commodities
including industrial minerals. There were 11,337 M/NM mines in the U.S.
in 1998, of which 9,769 (86%) were small mines and 1,568 (14%) were
large mines, using MSHA's traditional definition of small and large
mines. Based on SBA's definition, however, only 25 M/NM mines (0.2%)
were large mines.\1\
---------------------------------------------------------------------------

\1\ U.S. Department of Labor, MSHA, 1998 Final MIS data CM441
cycle 1998/198.
---------------------------------------------------------------------------

The data in Table V-1 indicate that employment at M/NM mines in
1998 was 195,557, of which 64,570 workers (33%) were employed by small
mines and 130,987 miners (67%) were employed by large mines, using
MSHA's definition. Based on SBA's definition, however, 170,584 workers
(87%) were employed by small mines and 24,973 workers (13%) were
employed by large mines. Using MSHA's definition, the average
employment is 7 workers at a small M/NM mine and 84 workers at a

[[Page 5887]]

large M/NM mine.\2\ Using SBA's definition, there are an average of 15
workers in each small M/NM mine and 888 workers in each large M/NM
mine.
---------------------------------------------------------------------------

\2\ U.S. Department of Labor, MSHA, 1998 final MIS data CM441
cycle 1998/198.
---------------------------------------------------------------------------

Metal Mining. There are about 24 metal commodities mined in the
U.S. Underground metal mines use a few basic mining methods, such as
room and pillar and block caving. The larger mines rely more heavily on
hydraulic drills and track-mounted haulage, and the smaller underground
metal mines rely more heavily on hand-held pneumatic drills
Surface metal mines normally include drilling, blasting, and
hauling; such processes are typical in all surface mines, irrespective
of commodity types. Surface metal mines in the U.S. rank among some of
the largest mines in the world.
Metal mines constitute 3 percent of all M/NM mines and employ 23
percent of all M/NM miners. Under MSHA's traditional definition of a
small mine, 45 percent of metal mines are small, and these mines employ
2 percent of all miners working in metal mines. Using SBA's definition,
94 percent of metal mines are small, and they employ 53 percent of all
miners working in metal mines.\3\
---------------------------------------------------------------------------

\3\ U.S. Department of Labor, Mine Safety and Health
Administration, Office of Program Policy Evaluation, Mine Employment
Size-Average Employment 1998.
---------------------------------------------------------------------------

Stone Mining. In the stone mining subsector, there are eight
different stone commodities, of which seven are further classified as
either dimension stone or crushed and broken stone. Stone mining in the
U.S. is predominantly by quarrying, with only a few slight variations.
Crushed stone mines typically drill and blast, while dimension stone
mines generally use channel burners, drills, or wire saws. Diesel
powered-haulage is used to transfer the broken rock from the quarry to
the mill where crushing and sizing are done.
Stone mines constitute 33 percent of all M/NM mines, and they
employ 41 percent of all M/NM miners. Using MSHA's definition of a
small mine, 71 percent of stone mines are small, and these mines employ
29 percent of all miners working in stone mines. Using SBA's
definition, 99.9 percent of stone mines are small, and they employ 99
percent of all miners working in stone mines.\4\
---------------------------------------------------------------------------

\4\ U.S. Department of Labor, Mine Safety and Health
Administration, Office of Program Policy Evaluation, Mine Employment
Size-Average Employment 1998.
---------------------------------------------------------------------------

Sand & Gravel Mining. Sand and gravel, for construction, is
generally extracted from surface deposits using dredges or draglines.
Further preparation involves washing and screening. As in other surface
mining operations, sand and gravel uses diesel-driven machines, such as
front-end loaders, trucks, and bulldozers, for haulage. The preparation
of industrial sand and silica flour involves the use of crushers, ball
mills, vibrating screens, and classifiers.
The sand and gravel subsector represents the single largest
commodity group in the U.S. mining industry when the number of mining
operations is being considered. Sand and gravel mines comprise 57
percent of all M/NM mines, and they employ 22 percent of all M/NM
miners. Using MSHA's definition of a small mine, 95 percent of sand and
gravel mines are small, and these mines employ 76 percent of all miners
working in sand and gravel mines. Using SBA's definition, almost 100
percent of sand and gravel mines are small, and they employ
approximately 42,800 miners.\5\
---------------------------------------------------------------------------

\5\ U.S. Department of Labor, Mine Safety and Health
Administration, Office of Program Policy Evaluation, Mine Employment
Size-Average Employment 1998.
---------------------------------------------------------------------------

Other Nonmetal Mining. For enforcement and statistical purposes,
MSHA separates stone and sand and gravel mining from other nonmetal
mining. There are about 35 other nonmetal commodities, not including
stone, and sand and gravel. Nonmetal mining uses a wide variety of
underground mining methods such as continuous mining (similar to coal
mining), in-situ retorting, block caving, and room and pillar. The
mining method is dependent on the geologic characteristics of the ore
and host rock. Some nonmetal operations use kilns and dryers in ore
processing. Ore crushing and milling are processes common to both
nonmetal and metal mining.
As with underground mining, there is a wide range of mining methods
utilized in extracting minerals by surface mining. In addition to
drilling and blasting, other mining methods, such as evaporation and
dredging, are also utilized, depending on the ore formation.
``Other'' nonmetal mines comprise 7 percent of all M/NM mines, and
they employ 14 percent of all M/NM miners. Using MSHA's definition of a
small mine, 66 percent of other nonmetal mines are small, and they
employ 12 percent of all miners working in these nonmetal mines. Using
SBA's definition, 99 percent of other nonmetal mines are small, and
they employ 92 percent of all miners working in these nonmetal
mines.\6\
---------------------------------------------------------------------------

\6\ U.S. Department of Labor, Mine Safety and Health
Administration, Office of Program Policy Evaluation, Mine Employment
Size-Average Employment 1998.
---------------------------------------------------------------------------

Economic Characteristics of the Metal/nonmetal Mining Industry. The
value of all M/NM mining output in 1998 was estimated at $40
billion.\7\ Metal mines, which include copper, gold, iron, lead,
silver, tin, and zinc mines, contributed $17.8 billion. Nonmetal
production was valued at $22.2 billion: $9.0 billion from stone mining,
$5.2 billion from sand and gravel, and $8 billion from other nonmetals
such as potash, clay, and salt.
---------------------------------------------------------------------------

\7\ U.S. Department of Energy, Energy Information
Administration, Annual Energy Review 1998, July 1999, pp. 3, 6, 142,
158, and 160.
---------------------------------------------------------------------------

The end uses of M/NM mining output are diverse. For example, iron
and aluminum are used to produce vehicles and other heavy duty
equipment, as well as consumer goods such as household equipment and
soft drink cans. Other metals, such as uranium and titanium, have more
limited uses. Nonmetals, like cement, are used in construction while
salt is used as a food additive and for road deicing in the winter.
Soda ash, phosphate rock, and potash also have a wide variety of
commercial uses. Stone and sand and gravel are used in numerous
industries and extensively in the construction industry.
A detailed economic picture of the M/NM mining industry is
difficult to develop because most mines are either privately held
corporations or sole proprietorships, or subsidiaries of publicly owned
companies. Privately held corporations and sole proprietorships are not
required to make their financial data available to the public. Parent
companies are not required to separate financial data for subsidiaries
in their reports to the Securities and Exchange Commission. As a
result, financial data are available for only a few M/NM companies, and
these data are not representative of the entire industry.
Adequacy of Miner Protection Provided by the Final Rule in
Underground Metal and Nonmetal Mines. In evaluating the rule for this
purpose, it should be remembered that MSHA has measured dpm
concentrations in this sector as high as 5,570DPM
g/m\3\--a mean of 808DPM g/m\3\. See Table
III-1 and Figure III-2 in part III of the preamble. As discussed in
detail in part III of the preamble, these concentrations place
underground metal and nonmetal miners at significant risk of material
impairment of their health,

[[Page 5888]]

and it does not appear there is any lower boundary to the risk.
Accordingly, in accordance with the statute, the Agency has to set a
standard which reduces these concentrations as much as is both
technologically and economically feasible for this sector as a whole.
Specifically, the standard establishes a concentration limit on
dpm. The concentration limit is the equivalent of about
200DPM g/m\3\ (as explained in Part IV, in the rule
the concentration limit is expressed in terms of a restriction on the
amount of total carbon because of the measurement system which MSHA
will utilize for compliance sampling).
Alternatives considered. In order to ensure that the maximum
protection that is feasible for the underground mining industry as a
whole is being provided, the Agency has considered three alternatives
that would provide greater protection: a lower concentration limit, a
significantly shorter implementation period, and requiring certain
categories of metal and nonmetal equipment to be filtered in addition
to observing a concentration limit. In addition, the agency has
considered whether the approach it is taking in underground coal mines
would be feasible in this sector. Specific alternatives and approaches
suggested by industry and labor are discussed in detail in part IV.
(1) Establish a lower concentration limit for underground metal/
nonmetal mines. Based on the Agency's risk assessment, a lower
concentration limit would provide more miner protection. The Agency has
concluded, however, that at this time it would not be feasible for the
underground metal and nonmetal sector to reach a lower concentration
limit. The problem is not technological feasibility, but rather
economic feasibility.
Technological feasibility of lower limit. In evaluating whether a
lower concentration limit is technologically feasible for this sector,
MSHA considered several examples of real-world situations. These
examples, and a detailed description of the methodology by which they
were developed, were published in the preamble to the proposed rule (65
FR 58198 et seq.). The examples were based on data about equipment and
ventilation from several actual underground metal and nonmetal mines: a
salt mine; an underground limestone mine that operates two completely
different shifts, one for production, and one for support; and a multi-
level underground gold mine. The data was placed into a computer model
to estimate the ambient dpm that would remain in a mine section after
the application of a particular combination of control technologies.
The details of this computer model, referred to as ``The Estimator'',
has subsequently been published in the literature (Haney and Saseen,
Mining Engineering, April 2000). The results for the salt and limestone
mines were written up in detail and placed into MSHA's record, with
actual mine identifiers removed; the study of the underground gold mine
is based on information supplied by inspectors, and all available data
was presented in the preamble to the proposed rule.
MSHA had picked these mines because the Agency originally thought
the conditions there were such that these mines would have great
difficulty in controlling dpm concentrations. As the results indicated,
however, even in these apparently difficult situations the
concentration of dpm could be lowered to well below 200DPM
g/m\3\ with readily available control techniques. Moreover as
noted above, MSHA can adopt a rule which is not feasible for every
mine; the standard is that the rule be feasible for the industry as a
whole.
MSHA did receive comments on the Estimator. However, no specific
examples of its application were received nor comments taking issue
with the examples discussed above. Specific comments received on the
Estimator are addressed in part IV.
Economic feasibility of lower concentration limit. MSHA estimates
that it will cost the underground metal and nonmetal industry about
$25.1 million a year to comply with a concentration limit of
160TC g/m\3\ (200DPM g/m\3\).
For an average underground metal and nonmetal dieselized mine that uses
diesel powered equipment, this amounts to about $128,000 per year.
The assumptions used in preparing the cost estimates for the final
review are discussed in detail in the Agency's REA. They are based on a
careful review of the evidence on the capabilities of various controls,
and a careful review of an economic analysis submitted on behalf of
several industry associations. That analysis estimated costs to be
three times as high as MSHA's initial estimate. MSHA's analysis and the
industry analysis agree on many of their assumptions; however, MSHA
believes the industry analysis to be an overestimation primarily
because it failed to properly optimize.
In general, MSHA has concluded that:
The interim standard of 400TC g/m\3\
(500DPM g/m\3\) will be met primarily through the
use of filters, but with cabs and ventilation in certain instances; and
The final standard of 160TC g/m\3\
(200DPM g/m\3\) will be met through the use of more
filters, ventilation changes, and the turnover in equipment and engines
to less polluting models that will have occurred by the time the final
standard goes into effect.
Based on its cost estimates, the Agency has concluded that this
sector would not find it economically feasible to reduce dpm
concentrations to a lower limit at this time. The incremental cost of
additional controls would rise sharply if the industry were required to
reach a substantially lower concentration level. It would begin to be
necessary to retrofit cabs on equipment that was not designed with cabs
and/or did not have off-the-shelf parts--at a cost per unit nearly
three times as great as the costs for more limited retrofitting of
suitably designed equipment. Additional ventilation improvements (e.g.,
new shafts) could easily run into the millions of dollars--compared
with the $300,000 estimate for more limited ``major system
improvements'' used in the cost analysis. Additional replacement of
engines beyond the natural turnover included in the baseline could run
as high as $27,500 for the engine itself, with additional costs
possibly as high as $65,000 for equipment modifications and
installation.
(2) Significantly shorten the phase-in time to reach the final
concentration limit in underground metal/nonmetal mines. Under the
rule, there is a phase-in period for a dpm concentration limit.
Operators have 18 months to reduce dpm concentrations in areas of the
mine where miners work or travel to 400TC g/m\3\
(500DPM g/m\3\), and up to 60 months in all to
reduce dpm concentrations in those areas to 160TC
g/m\3\ (200DPM g/m\3\).
MSHA has established this phase-in period because it has concluded
that it is economically infeasible for the underground metal and
nonmetal mining industry as a whole to implement the requirements
sooner. The costs of the rule would increase significantly were the
final concentration limit to become effective significantly sooner. For
example, the turnover of the fleet to less polluting engines would not
be as complete by the time the final limit goes into effect; hence,
operators would be required to purchase new engines ahead of schedule.
Moreover, a substantial portion of the costs to implement these
provisions were calculated using a 5-year discounting process to
reflect the phase-in schedule.

[[Page 5889]]

Technological feasibility problems might also be more frequent with
a quicker implementation schedule. The rule includes a provision for a
special time extension to deal with unique situations; shortening the
normal time frame available to this sector would tend to increase the
frequency upon which operators would have to apply for such extensions.
Accordingly, MSHA has concluded that, for the underground metal and
nonmetal sector as a whole, a significantly accelerated approach would
not be feasible.
(3) In addition to a concentration limit, require certain types of
equipment to utilize an 80% efficiency filter. This approach would help
reduce dpm concentrations in localized areas of a mine, and ensure that
problems with ventilation controls will have less of an impact on miner
exposures. Most filters can meet the 80% requirement. The requirement
could be applied: (a) just to loading and hauling equipment (e.g.,
trucks and loaders); (b) to the equipment in (a) plus equipment used in
the production process (e.g., drills, powered trucks); (c) to the
equipment in (a) and (b) and also direct support equipment (e.g.,
scalers, lube trucks, generators, compressors and pumps); or (d) to all
equipment except personnel carriers and supply trucks.
Such an approach would limit operator flexibility on controls--the
broader the requirement, the less the flexibility. And it would
increase expense, since the most efficient way to achieve compliance
with the concentration limit might well be another type of control
(e.g., new engine, cab, ventilation, etc.). Accordingly, MSHA has
determined that this approach would be infeasible for this sector at
this time.
(4) In lieu of a concentration limit, require certain types of
equipment to reach tailpipe limits. In the underground coal sector,
MSHA is requiring various categories of equipment to meet specific
tailpipe limits. Compliance with these limits is determined through
laboratory tests of engines and control devices. This approach avoids
questions about MSHA in-mine compliance sampling which have been the
focus of much discussion in coal mining. Accordingly, MSHA considered
requiring a similar approach in underground metal and nonmetal mines.
However, the agency determined that this would not be practical,
because the engines in the current fleet are not approved; hence, the
agency lacks information on their emission rates, a key piece of
information needed to implement a tailpipe standard. Moreover, in many
cases a cab or ventilation change might be a more effective solution to
a localized dpm concentration in an underground metal and nonmetal mine
than a change in the engine or emission control device--and perhaps
less expensive for equipment of this size. One of the advantages of a
concentration limit is the flexibility of controls that the operator
can apply to meet the limit.
Feasibility of the final rule for underground metal and nonmetal
mining sector. The Agency has carefully considered both the
technological and economic feasibility of the rule being promulgated
for the underground metal and nonmetal mining sector as a whole.
Technological feasibility of final rule. There are arguably two
separate issues with respect to technological feasibility--(a) the
existence of technology that can accurately and reliably measure dpm
concentration levels in all types of underground metal and nonmetal
mines; and (b) the existence of control mechanisms that can bring dpm
concentrations down to the proposed limit in all types of underground
metal and nonmetal mines. Both have been addressed elsewhere in this
preamble.
The first of these questions, concerning measurement, is reviewed
in considerable detail in section 3 of Part II and in the discussion of
section 57.5061 of the rule in Part IV. For the reasons set forth in
those discussions, MSHA has concluded that with the use of a
submicrometer sampler as required by the final rule, and with a
sampling strategy that avoids the inteferences which can compromise
individual samples in certain situations, it does have a
technologically feasible measurement method that operators and the
agency can use to determine if the limits established by the standard
are in fact being met.
The second of these questions, concerning controls, is discussed
earlier in this part [See ``(1) Establish a lower concentration limit
for underground metal/nonmetal mines'']. MSHA has performed various
studies which suggest that even in the most difficult situations, it is
technologically feasible for operators to meet the rule's final
concentration limit. In fact, these studies suggest it is
technologically feasible for operators in this sector to reduce their
dpm concentrations to an even lower concentration limit. In addition,
as discussed in section 6 of Part II of this preamble, considerable
progress has been made in recent years on the effectiveness of filters
and cabs. MSHA very carefully reviewed this information with reference
to the kinds of engines and equipment found in underground metal and
nonmetal mines, and their ventilation, and is confident that the final
rule is technologically feasible.
Although the agency has reached this conclusion, and moreover knows
of no mine that cannot accomplish the required reductions in the
permitted time, it has nevertheless retained in the final rule a
provision that any underground metal or nonmetal mine may have up to an
additional two years to install the required controls should it find
that there are unforseen technological barriers to timely completion. A
detailed discussion of the requirements for obtaining approval for such
an extension of time to comply is provided in part IV of the preamble.
Economic Feasibility. MSHA estimates that the rule would cost the
underground metal and nonmetal sector about $25.1 million a year even
with the extended phase-in time. The costs per underground dieselized
metal or nonmetal mine are estimated to be about $128,000 annually. The
yearly cost of the final rule represents about 0.67 percent of yearly
industry revenue. MSHA uses a one-percent ``screen'' of costs relative
to revenues as a presumptive benchmark of economic feasibility.
Therefore, since the cost of the rule is less than one percent of
revenues, MSHA anticipates that (subject to contrary evidence) the rule
is economically feasible for the dieselized underground M/NM mining
sector as a whole. Note, however, that the costs are sufficiently close
to one percent of revenues that the rule could threaten the economic
viability of affected mines on the economic margin and that more costly
regulatory alternative could conceivably threaten the economic
viability of a substantial fraction of this mining sector.
As explained in the REA, nearly all ($24.1 million) of the
anticipated yearly costs would be investments in equipment to meet the
interim and final concentration limits. While operators have complete
flexibility as to what controls to use to meet the concentration
limits, the Agency based its cost estimates on the assumption that
operators will ultimately need the following to get to the final
concentration limit: (a) Fifty percent of the fleet will have new
engines (these new engines do not impact cost of the rule). It is
expected that the new engines will be more expensive and
technologically superior to the ones that they replace. One aspect of
this technological superiority will be substantially lower DPM
emissions. It does not follow, however, that the

[[Page 5890]]

greater expense of these engines is an impact of this rule. Mine
operators will not replace existing engines with the same type or model
of engine. New engine technology makes engines much more efficient and
productive than existing older engines. Particularly on larger
equipment, greater productivity makes new engines an attractive
investment that will pay back the greater costs. Moreover, due to EPA
regulations which will limit DPM emissions from engines used in surface
construction, surface mining, and over-the-road trucks (the major
markets for heavy duty diesel engines), the market for low tech,
``dirtier'' engines will dry up. Underground mine operators will thus
purchase high tech, cleaner engines because they will be the only
engines available for purchase.
(b) One hundred percent of the production equipment and about fifty
percent of the support equipment will be equipped with filters; (c)
about thirty percent of all equipment will need to be equipped with
environmentally controlled cabs; (d) twenty three percent of the mines
will need new ventilation systems (fans and motors): (e) forty percent
of the mines will need new motors on these fans; and (f) thirty two
percent of the mines will need major ventilation upgrades.
The Agency is taking a number of steps to mitigate the impact of
the rule for the underground metal and nonmetal sector, particularly on
the smallest mines in this sector. These are described in detail in the
Agency's Regulatory Flexibility Analysis, which the Agency is required
to prepare under the Regulatory Flexibility Act in connection with the
impact of the rule on small entities. (The regulatory flexibility
analysis can be found in part VI of this preamble, or packaged with the
Agency's REA.)
Based on its cost estimates, the Agency has concluded that this
sector would not find it economically feasible to reduce dpm
concentrations to a lower limit at this time. These assumptions and the
rationale behind them are discussed in greater detail in the beginning
of Chapter IV of the Regulatory Economic Analysis.
After a careful review of the information about this sector
available from the industry economic profile, and the other obligations
of this sector under the Mine Act, MSHA has concluded that a reasonable
probability exists that the typical firm in this sector will be able at
this time to afford the controls that will be necessary to meet the
proposed standard.
Conclusion: metal and nonmetal mining sector. Based on the best
evidence available at this time, the Agency has concluded that the
final rule for the underground metal and nonmetal sector meets the
statutory requirement that the Secretary attain the highest degree of
health and safety protection for the miners in that sector, with
feasibility a consideration.

VI. Regulatory Impact Analyses

This part of the preamble reviews several impact analyses which the
Agency is required to provide in connection with its final rulemaking.
The full text of these analyses can be found in the Agency's Regulatory
Economic Analysis (REA).

(A) Costs and Benefits: Executive Order 12866

In accordance with Executive Order 12866, MSHA has prepared a
Regulatory Economic Analysis (REA) of the estimated costs and benefits
associated with the final rule for the underground metal and nonmetal
mining sector.
The key conclusions of the REA are summarized, together with cost
tables, in part I of this preamble (see Item number 7). The complete
REA is part of the record of this rulemaking, and is available from
MSHA.
The Agency considers this rulemaking ``significant'' under section
3(f) of Executive Order 12866, and has so designated the rule in its
semiannual regulatory agenda (RIN 1219-AA74). However, based upon the
REA, MSHA has determined that the final rule does not constitute an
``economically significant'' regulatory action pursuant to section
3(f)(1) of Executive Order 12866.

(B) Regulatory Flexibility Act (RFA)

Introduction

In accordance with section 605 of the Regulatory Flexibility Act of
1980 as amended, MSHA has analyzed the impact of the final rule on
small businesses. Further, MSHA has made a determination with respect
to whether or not it can certify that this final rule will not have a
significant economic impact on a substantial number of small entities
that are affected by this rulemaking. Under the Small Business
Regulatory Enforcement Fairness Act (SBREFA) amendments to the
Regulatory Flexibility Act (RFA), MSHA must include a factual basis for
this certification. If the final rule does have a significant economic
impact on a substantial number of small entities, then the Agency must
develop a final regulatory flexibility analysis.
The Agency has, as required by law (5 U.S.C. 605), developed a
final regulatory flexibility analysis which is set forth Chapter V of
the REA. In addition to a succinct statement of the objectives of the
final rule and other information required by the Regulatory Flexibility
Act, the analysis reviews alternatives considered by the Agency with an
eye toward minimizing the economic impact on small business entities.

Definition of a Small Mine

Under the RFA, in analyzing the impact of a rule on small entities,
MSHA must use the Small Business Administration (SBA) definition for a
small entity or, after consultation with the SBA Office of Advocacy,
establish an alternative definition for the mining industry by
publishing that definition in the Federal Register for notice and
comment. MSHA has not taken such an action, and hence is required to
use the SBA definition.
The SBA defines a small entity in the mining industry as an
establishment with 500 or fewer employees (13 CFR 121.201). Of the 196
underground M/NM mines that use diesel powered equipment and are
therefore affected by this rulemaking, 189 (or all but 7) fall into
this category and hence can be viewed as sharing the special regulatory
concerns that the RFA was designed to address.
Traditionally, the Agency has also looked at the impacts of its
rules on a subset of mines with 500 or fewer employees \3/4\ those with
fewer than 20 employees, which the mining community refers to as
``small mines.'' The way these small mines perform mining operations is
generally recognized as being different from the way larger mines
operate. These small mines differ from larger mines not only in the
number of employees, but also, among other things, in economies of
scale in material produced, in the type and amount of production
equipment, and in supply inventory. Therefore, their costs of complying
with MSHA rules and the impact of MSHA rules on them will also tend to
be different. It is for this reason that ``small mines,'' as
traditionally defined by the mining community, are of special concern
to MSHA.
This analysis complies with the legal requirements of the RFA for
an analysis of the impacts on ``small entities'' while continuing
MSHA's traditional look at ``small mines.'' MSHA concludes that the
final rule would not have a significant economic impact on small
entities, as defined by SBA, when considered as a group. However, MSHA
has determined that the final rule arguably would have a significant
economic impact on a subset of small entities that are covered by this

[[Page 5891]]

rulemaking. That subset is small underground M/NM mines as
traditionally defined by MSHA, those mines with fewer than 20
employees. This subset of affected mines constitutes a substantial
number of small entities.

Screening Analysis

General Approach. The Agency's analysis of impacts on ``small
entities'' begins with a ``screening'' analysis. The screening compares
the estimated compliance costs of a rule for small entities in the
sector affected by the rule to the estimated revenues for those small
entities. When estimated compliance costs are less than 1 percent of
the estimated revenues (for the size categories considered), the Agency
believes it is generally appropriate to conclude that there is no
significant economic impact on a substantial number of small entities.
When estimated compliance costs exceed 1 percent of revenues, it tends
to indicate that further analysis may be warranted.
Derivation of Costs and Revenues. The compliance costs presented
here were previously introduced in Chapter IV of the REA along with an
explanation of how they were derived. Table VI-1 summarizes the total
yearly cost of the final rule by mine size.

BILLING CODE 4510-43-P

[[Page 5892]]

[GRAPHIC] [TIFF OMITTED] TR19JA01.076

BILLING CODE 4510-43-C

[[Page 5893]]

Data on underground M/NM mines published by the U.S. Geological
Survey \1\ were used for tonnage and value of underground M/NM mines.
These data, however, are not disaggregated by mine size class. MSHA
collects data, by mine size, on both average employees and employee
hours.\2\ MSHA has used these data to estimate revenues by mine size
class.
---------------------------------------------------------------------------

\1\ U.S. Geological Survey, ``Mineral Industry Surveys: Mining
and Quarrying Trends, 1998 Annual Review, April 2000.
\2\ U.S. Department of Labor, MSHA, 1998 Final MIS data CM441
cycle 1998/198.
---------------------------------------------------------------------------

MSHA has assumed that tonnage is proportional to employee hours.
This assumption (rather than proportionality with employees) implicitly
adjusts for different shift lengths associated with different sizes of
mines. MSHA has also assumed that all underground M/NM mines use diesel
powered equipment.\3\ Using these assumptions, MSHA has computed the
percentages of employee hours of all underground M/NM mines that are
accounted for by each size class. MSHA estimates that these percentages
of total revenues are accounted for by the different mine size classes.
---------------------------------------------------------------------------

\3\ This assumption ignores the fact that some very small mines
do not use diesel powered equipment. MSHA believes, however, that
these mines are generally very small (even among the mines with
fewer than 20 employees) and that many of them operate only
intermittently. Thus they account for employee hours proportionately
far less than their numbers. Accordingly, MSHA believes that the
most accurate way to interpret the data is to disregard the fact
that these mines do not use diesel powered equipment.
---------------------------------------------------------------------------

Results of the Screening Analysis. The final rule applies to
underground M/NM mines that use diesel-powered equipment. Table VI-1
shows that the estimated yearly cost of the final rule as a percentage
of yearly revenues is about 0.8 percent for the affected underground M/
NM mines with 500 or fewer employees.
However, for a subset of affected underground M/NM mines, those
with fewer than 20 employees, estimated yearly costs are equal to about
2.16 percent of yearly revenues for this subset of mines. The economic
impact on these small mines, which constitute a substantial number of
small entities affected by the final rule, is larger than one percent
of their revenues. MSHA therefore cannot certify that the final rule
would not have a significant impact on a substantial number of small
entities.
The Agency has prepared a final regulatory flexibility analysis, as
required by law, which explains the steps MSHA has taken to minimize
the burden on these small entities and justifies the costs placed on
them.

Table VI-2.--Estimated Yearly Costs of Final Rule Relative to Yearly Revenues for Underground Coal Mines That
Use Diesel-Powered Equipment
----------------------------------------------------------------------------------------------------------------
Final rule Costs as
Mine size yearly costs Revenuesa (In Percentage of
(In thousands) thousands) revenues
----------------------------------------------------------------------------------------------------------------
20 emp.......................................................... $4,093 $189,305 2.16
500 emp.............................................. 21,837 2,745,137 0.80
----------------------------------------------------------------------------------------------------------------
a Source: Mine Safety and Health Administration, Office of Injury and Employment Information, Denver, Colorado.
1999, and U.S. Department of Energy, Energy Information Agency, Annual Energy Review 1998, DOE/EIA0384(98),
July 1999, p.203.

Final Regulatory Flexibility Analysis

As indicated above, the estimated yearly cost of the final rule on
a subset of small entities, those with fewer than 20 employees, is 2.16
percent of yearly revenue. This percentage is just over twice the value
(1.0 percent) below which MSHA could say with reasonable confidence
that the final rule does not have a significant economic impact on a
substantial number of small entities. Accordingly, MSHA has prepared a
final regulatory flexibility analysis.

Need for, and Objectives of, the Rule

Need. The rule is needed because underground miners in mines that
use diesel powered equipment are currently exposed to extremely high
concentrations of diesel particulate matter (DPM). Based on MSHA field
studies, median DPM concentrations to which underground miners are
exposed range up to 200 times as high as average environmental
exposures in the most heavily polluted urban areas and up to 10 times
as high as median exposures estimated for the most heavily exposed
workers in any occupational group other than underground miners.
The available scientific information indicates that miners exposed
to the extremely high DPM concentrations found in underground mines are
at significant excess risk of experiencing three kinds of material
impairment to their health:
Increased risk of lung cancer has been linked to chronic
occupational DPM exposure.
Increased acute risk of death from cardiovascular,
cardiopulmonary, or respiratory causes has been linked to short or long
term DPM exposures.
Sensory irritations and respiratory symptoms can result
from even short term DPM exposures. Besides being potentially
debilitating, such effects can distract miners from their
responsibilities in ways that could pose safety hazards for everyone in
the mine.
Although definitive dose-response relationships have not yet been
established (especially for the acute effects), the best available
evidence indicates that the risks are substantial.
Objective. The objective of the rule is to lower DPM exposures in
underground M/NM mines to concentrations similar to the worst levels to
which other occupational groups are exposed. By doing so, the rule is
designed substantially to lower the health risks associated with DPM.
Expected benefits include an estimated minimum of 8.5 lung cancer
deaths avoided per year.

Significant Issues Raised in Response to the Initial RFA

Comments. The principal issue raised in comments on the PREA was
that, for a variety of reasons, MSHA had substantially understated the
costs of controlling DPM. The implication of these comments was that
the rule was economically infeasible. The most comprehensive comments
along these lines were by Head,\4\ who argued (among other things) that
MSHA had made the following errors and omissions in its analysis:
---------------------------------------------------------------------------

\4\ H. John Head, Principal Mining Engineer, Harding Lawson
Associates, ``Review of Economic and Technical Feasibility of
Compliance Issues Related to: Department of Labor--MSHA, 30 CFR Part
57--Proposed Rule for Diesel Particulate Matter Exposure of
Underground Metal and Nonmetal Miners,'' Report prepared under
contract with the National Mining Association, July 21, 1999.
---------------------------------------------------------------------------

MSHA had (according to Head) understated the numbers of
machines and mines affected, including:

[[Page 5894]]

Understatement of the number of diesel units in
underground M/NM mines by more than 50 percent, and
Understatement of the number of ventilation upgrades
needed by 20 percent to 40 percent
MSHA had understated a number of costs, including:
Understatement of the cost of replacement engines by up to
one third,
Understatement of the costs of filters on larger engines
by 20 percent, and
Understatement of the costs of vehicle cabs by about 60
percent.
MSHA had omitted some costs entirely, including:
Installation costs of retrofitting new engines in old
equipment, which ran as high as three times the costs of the engines
themselves, and
Major ventilation improvements needed by about one third
of the mines.
Based on his own numbers, Head estimated compliance costs to be
three times as high as MSHA's estimate of the cost of the proposed rule
of $19.2 million.
Analytical Assessment of Issues. MSHA considered the comments and
reviewed its assessment of costs very carefully. The assessment focused
on Head's comments, since his exposition was detailed enough for
analysis of the basis of his estimates. MSHA responded in a variety of
ways, which are summarized below.
The key to the issue of the number of diesel units affected by the
rule was how one interpreted the number. MSHA resolved this issue by
recognizing that not all diesel powered equipment would be affected in
the same manner. In fact, the machines in Head's total count should be
grouped into three categories: active, spares, and disused. Active
diesel powered equipment (essentially MSHA's original count) needs to
be fitted for everyday use. Spare equipment needs to be controlled for
occasional use as back-up. Disused equipment is essentially not
affected by the rule. A shift in the principal control strategy from
engine replacement to ceramic filters (discussed further below) made
these distinctions operational. With ceramic filters, both active and
spare equipment can be fitted with filters (a relatively inexpensive
operation), but filters need to be regenerated and changed (which
encompasses most of the costs) only to the extent that the equipment is
actually used.
MSHA believes that Head was simply wrong about the number of mines
needing upgrades to their ventilation systems. Head appeared to believe
that MSHA's count was arbitrary, and the basis for his proposed number
was obscure. In fact, MSHA has based its count on mine-specific data on
the existence and rate of air flow of ventilation systems. Thus, MSHA
retained its original count.
MSHA's review of comments on costs produced different conclusions
for different specific costs:
MSHA accepted and used Head's estimate of costs of ceramic
filters.
MSHA does not entirely agree with Head's estimates of
costs of new engines. Moreover, expensive new engines are
technologically advanced and tend to produce substantial gains in
productivity and savings in operating costs, which Head did not
consider. The issue of engine costs became irrelevant, however, under a
strategy of filters as the first-used control device.
MSHA's re-examination of the costs of cabs indicated that
MSHA's cost estimate is appropriate for equipment for which equipment
manufacturers can provide off-the-shelf kits for retrofitting
equipment, and Head's cost estimate is appropriate for equipment for
which cabs have to be custom designed and retrofitted. Since the rule
does not mandate cabs and MSHA expects cabs to be used on a relatively
small proportion of equipment, however, MSHA believes that mine
operators will not retrofit equipment for which cabs would need to be
custom designed. Accordingly, MSHA has retained its original cost
estimate.
Head concurred with MSHA on the costs of ventilation
improvements. While these costs appear to be an appropriate average
estimate for M/NM mines as a whole, there is a distinct possibility
that they may be too high for very small M/NM mines.\5\ In the context
of regulatory flexibility analysis, MSHA considers these cost estimates
to be fairly conservative.
---------------------------------------------------------------------------

\5\ The issue is further complicated by the fact that mines that
are ``small'' in terms of employment vary considerably among
commodities and mining techniques in their physical size and
ventilation requirements. Accordingly, MSHA has not attempted to
make a separate cost estimate of ventilation improvement costs for
``small'' M/NM minas as a group.
---------------------------------------------------------------------------

MSHA agrees that certain costs were omitted, but the conclusions of
MSHA's reconsideration of these costs also vary with the cost:
MSHA has accepted Head's estimates for major ventilation
improvements and has included them in the analysis of costs.
Head's comment that MSHA had omitted the costs of
retrofitting new engines in old equipment is correct, although MSHA
does not agree with the size of Head's cost estimates. The key issue,
however, is that the strategy of relying primarily on filters does not
entail retrofitting engines. Thus Head's comment is not germane.
Concentration Limits and the Toolbox. This standard for underground
M/NM mines is a performance standard, with an interim DPM concentration
limit of 500 micrograms/m\3\, followed by a final DPM concentration
limit of 200 micrograms/m\3\. The rule encourages mine operators to use
any combination of a ``toolbox'' of measures to meet these
concentration limits. For cost estimation purposes, however, it is
necessary to assume a specific set and sequence of control measures.
Specifically, in the PREA MSHA assumed that:
The interim standard would be met by replacing engines,
installing oxidation catalytic converters, and improving ventilation;
and
The final standard would be met by adding cabs and
filters.
Both the general strategy and the specific proportions of diesel
powered equipment to be controlled by each measure were based on an
optimizing approach, in which the most cost-effective additional
measures were selected for additional DPM reductions at each stage.
In his comments, Head exactly replicated MSHA's assumptions about
how many pieces of each kind of diesel equipment would be controlled,
how they would be controlled, and the sequence in which controls would
be used. Although his cost estimates differed substantially from
MSHA's, Head made no attempt to optimize the use of DPM control
``tools'' from the toolbox.
Substantially the most important of Head's changes is to make
filters much cheaper, relative to engine replacement. At the same time,
data collected by MSHA since publication of the PREA indicate that
filters are more effective than was previously understood. This finding
has further enhanced the cost-effectiveness of filters, relative to
engine replacement. These changes in information have caused MSHA to go
back to the toolbox and rethink the optimized compliance strategy. The
revised compliance strategy, upon which MSHA bases the revised
estimates of compliance costs, reverses the two most widely used
measures from the toolbox. MSHA now anticipates that:
The interim DPM standard of 500 micrograms/m\3\ will be
met with filters, cabs, and ventilation; and
The final DPM standard of 200 micrograms/m\3\ will be met
with more filters, ventilation, and such turnover in

[[Page 5895]]

equipment and engines as will have occurred in the baseline.
This new approach uses the same toolbox and optimization strategy
that was used in the PREA. Since relative costs are different, however,
the tools used and costs estimated are quite different. The effects on
costs is substantial. Most of the difference between Head's cost
estimate and the cost estimate in the REA is attributable to this
change in strategy.
Changes in the Rule. Because the rule is a performance standard
that uses a tool-box approach, most modifications that MSHA made in
response to comments involved changes in the mix of tools within the
framework of the rule, rather than changes in the rule per se. MSHA did
make one significant change in the rule itself, however, by allowing
compliance with listed EPA standards as a substitute for MSHA approval
of new engines. Because most engines used in underground M/NM mining
equipment are essentially the same engines used on the surface, which
fall under EPA regulations, MSHA believes that virtually all new
engines used in mining equipment will meet EPA standards. Therefore,
this change resulted in eliminating a cost of approval that was
estimated in the PREA to average $2,500 per new engine.

Small Entities to Which the Rule Will Apply

For the purposes of this regulatory flexibility analysis, the
working definition of ``small'' is MSHA's definition of fewer than 20
employees. (Although SBREFA requires use of the SBA's definition, the
impacts on mines with 500 or fewer employees as a whole are not
economically significant.) Correspondingly, one element of a regulatory
flexibility analysis involves developing a more focused definition of
``small.''
There are 77 M/NM mines that are ``small'' by this definition.
These mines fall in four commodity groups:
Stone is the largest group, accounting for 54 small
underground M/NM mines that use diesel equipment (70 percent). These
mines include limestone (46 mines), marble (5 mines), lime (2 mines),
and granite (1 mine).
Precious metals account for 10 small underground M/NM
mines that use diesel equipment (13 percent). Most of these (9 mines)
are gold mines; one mines both gold and silver.
Other metals account for 4 small underground M/NM mines
that use diesel equipment (5 percent). These mines include zinc (2
mines), copper (1 mine), and a combination of copper and zinc (1 mine).
The other 9 small underground M/NM mines that use diesel
equipment (12 percent) are a miscellany that includes shale (3 mines)
as well as calcite, clay, gemstone, perlite, sand (industrial), and
talc (1 mine each).
Collectively, these 77 mines have estimated revenues of $189.3
million, or an average of $2.46 million per mine. The estimated total
costs of the rule are $4.1 million, or an average of $53,160 per mine.
Estimated costs of the rule are 2.16 percent of estimated revenues.
Costs by Commodity Group and Mine Size. Table VI-3 shows the
estimated yearly cost by size class for each commodity group in M/NM
mines. Costs for Section 57.5060(a) and Section 57.5060(b) were
recalculated for each commodity group, based on the diesel powered
equipment and air flow of the mines in each commodity group. All other
costs were very small, probabilistically distributed among mines, and/
or essentially constant for all mines or for all mines in a size class.
For these costs, the average cost per mine in each size class (from
Table VI-1) was used, as very little precision was lost through this
simpler estimation procedure. Table VI-3 shows a fair degree of
variation among commodity groups.
For mines with fewer than 20 employees, the average cost
per mine is estimated to be $53,158, and estimated costs per mine for
commodity groups range from $31,500 to $60,500, with:
Costs above average for stone mines ($60,500) and base
metal ($54,400), and
Costs below average for other M/NM mines ($31,500) and
gold mines ($34,600).
For mines with 20 to 500 employees, the average cost per
mine is estimated to be $158,437, and estimated costs per mine for
commodity groups range from $102,100 to $201,700, with:
Costs above average for base metal mines ($201,700) and
gold mines ($171,900),
Costs roughly average for stone mines ($150,900) and
evaporates mines ($149,100), and
Costs below average for other M/NM mines ($102,100).
For mines with over 500 employees, the average cost per
mine is estimated to be $473,078, and estimated costs per mine for
commodity groups range from $291,800 to $660,300, with:
Costs above average for gold mines ($660,300) and base
metal mines ($592,300), and
Costs below average for evaporates mines ($291,800) and
stone mines ($298,000).

BILLING CODE 4510-43-P

[[Page 5896]]

[GRAPHIC] [TIFF OMITTED] TR19JA01.077

BILLING CODE 4510-43-C

[[Page 5897]]

Thus by overall commodity group:
Compliance costs are relatively high in gold mines (except
for small mines) and base metal mines,
Compliance costs are relatively low in evaporates mines
and other M/NM mines, and
Compliance costs of stone mines show no consistent pattern
relative to average costs for all M/NM mines.
The differences in cost per mine appear to be attributable to the
interaction of three characteristics of the mines, which are included
in Table VI-4:
The percentage of mines that need new ventilation systems;
The number of diesel powered machines per mine; and
The proportion of diesel powered equipment that is large
production equipment.
[GRAPHIC] [TIFF OMITTED] TR19JA01.078

[[Page 5898]]

These three characteristics interact in somewhat different ways in
the different mine size classes:
For mines with fewer than 20 employees, the cost per mine
is:
Relatively high (or just above average) in commodity
groups where two or all three of these factors have relatively high
values, and
Relatively low when two of these factors have relatively
low values.
For mines with 20 to 500 employees, the cost per mine is:
Relatively high in commodity groups where the number of
machines per mine and the proportion of machines that are large
production equipment are both relatively large,
Average when one of these two factors is relatively high
and the other is relatively small, and
Relatively low when all three of the factors have
relatively low values.
For mines with over 500 employees (none of which need new
ventilation systems), the cost per mine is:
Relatively high in commodity groups where the number of
machines per mine is relatively large, and
Relatively low when the number of machines per mine or the
proportion of machines that are large production equipment is
relatively small.
Impacts on Small Mines by Commodity Group. The available data are
not adequate to support a realistic estimate of impacts on small
underground M/NM mines by commodity group, since revenues of individual
commodities cannot be allocated to different size classes of mine. The
analysis of costs per mine suggests, however, that stone is the only
commodity group with impacts much above average. The costs per small
stone mine are 13.6 percent higher than the average for all small
underground M/NM mines. Impacts on small underground mines in other M/
NM commodity groups appear to be about average or less.

Projected Reporting, Recordkeeping, and Other Requirements of the
Rule

The rule requires several types of records and reports. Plans are
required in conjunction with respirator use and DPM control if the
concentration levels are violated, and these must be posted and
provided to various parties. An extension may be applied for.
Maintenance training, miner health training, and respirator training
must be logged. Environmental monitoring results must be recorded and
provided to miners upon request. While there are a number of reporting
and recordkeeping requirements, however, each one is straightforward,
and most are no more than the simplest form of documentation. Thus the
total cost of recordkeeping is only about 0.35 percent of the
compliance costs for small mines.
The principal source of costs of the rule is controls to reduce the
DPM concentrations in underground mines. MSHA has adopted a flexible
``toolbox'' approach that allows mine operators to select the controls
that will be most cost-effective for their mines. MSHA has based its
cost estimates on extensive use of ceramic filters, less widespread use
of cabs on equipment, and ventilation upgrades. MSHA also assumes that
new diesel engines introduced into the mines as part of the baseline
turnover of the fleet and its engines will be relatively clean and will
contribute to reduced DPM levels. These control costs account for an
estimated 95.6 percent of the yearly compliance costs of small mines.
Of these costs, ventilation costs (47.1 percent) and filter costs (46.3
percent) account for nearly half each, while the cost of cabs (6.6
percent) is relatively minor.
Only two other requirements impose costs of any size. Environmental
monitoring accounts for about 2.6 percent of the estimated compliance
costs of small mines. Occasional use of respirators (equipment,
training, inspection, etc.) accounts for about 1.6 percent of estimated
compliance costs. Maintenance training and miner health training
account for less than 0.2 percent of compliance costs. The non-control
requirements of the rule are quite modest.

Steps Taken to Minimize Impacts on Small Entities

Constraints of the Mine Safety and Health Act. The Federal Mine
Safety and Health Act of 1977 was enacted to protect miners. MSHA has
always read the Act to prohibit discriminating among miners by
providing different degrees of protection that varied systematically
with the size of the mine in which they worked. Accordingly, the Mine
Safety and Health Act rules out certain classes of regulatory
flexibility alternatives, particularly exemption of small mines, but
also any alternative that would result in systematically higher
allowable DPM concentration levels in small mines. Because over 95
percent of the yearly costs to be incurred by small mines are directly
related to protection, there is little scope for distinct provisions
for small mines.
Built-In Flexibility. To minimize impacts on small entities, MSHA
has taken steps to build as much flexibility into the rule itself as
possible. The rule itself is a performance standard that allows mine
operators to meet the DPM concentration limits with their own choice of
``tools.'' While MSHA has selected a specific set of tools for the cost
analysis, MSHA expects that operators of specific mines probably will
often be able to come into compliance at lower costs by using a mix of
techniques tailored to that specific mine.
Other parts of the rule provide similar flexibility. Training and
recordkeeping requirements indicate the information to be imparted or
retained, for example, but they do not spell out how this is to be
done. Much of the reporting is required only upon request, rather than
routinely. Where a requirement (e.g., MSHA approval of new engines)
appeared to be relatively expensive, MSHA added an alternative
(compliance with listed EPA standards).
Phasing in over five years is another element that MSHA has
incorporated to minimize impacts (albeit for all mines, not just for
small ones). This not only defers costs, it allows impacts to be
reduced in a number of ways. Mine operators can spread major expenses
out to avoid a capital crunch. To a great degree, mine operators will
be able to take advantage of the natural turnover of their fleets,
rather than doing extensive (and more expensive) retrofitting. In
extreme cases, if a mine is quite marginal and/or is likely to shut
down in a few years anyway, the five-year phase-in allows an orderly
closure that minimizes impacts.
Low Risk of Short-Term Closures. Ultimately, the issue of concern
related to impacts whether mines may be forced to close. When costs are
a significant but relatively small fraction of revenues (or profits),
however, it is especially difficult to determine whether closure is an
impact resulting from the rule or a baseline event that would have
happened anyway. Given the fact that profits fluctuate widely over
time, even the presence of losses is not necessarily a good indicator
of whether businesses will recover or fail. In many cases where a
business does fail, the true impact of a regulation is not causing its
failure but rather hastening its failure. Because of the phasing of
this rule, it affords an opportunity to consider the potential for
hastening the failure of a small mine.
If a mine is likely to close within five to seven years without the
regulation, the impacts of the rule are different from the above
analysis. In order to stay open for five years, a mine need only comply
with the interim DPM concentration level. To this end, it needs to
incur the costs of:

[[Page 5899]]

Control costs necessary for Section 57.5060(a); \6\
Respirator protection costs of Section 57.5060(d); \7\
DPM control plan costs of Section 57.5062; \8\
---------------------------------------------------------------------------

\6\ These controls include ceramic filters and cabs, but not
ventilation (which MSHA did not estimate to be necessary for the
interim DPM level. These costs, amortized over 5 years at an annual
discount rate of 7.0 percent, are $1,119,800 for filters and
$150,437 for cabs.
\7\ These costs, amortized over 5 years at an annual discount
rate of 7.0 percent, are $164,845.
\8\ Annual costs are $1,408.
---------------------------------------------------------------------------

Maintenance training, tagging, and examination costs of
Section 57.5066(b) and Section 57.5066(c);\9\
---------------------------------------------------------------------------

\9\ These costs, amortized over 5 years at an annual discount
rate of 7.0 percent, are $5,681.
---------------------------------------------------------------------------

Miner Health Training costs of Section 57.5071; \10\
---------------------------------------------------------------------------

\10\ Annual costs are $5,226.
---------------------------------------------------------------------------

Environmental monitoring costs of Section 57.5071; \11\
and
---------------------------------------------------------------------------

\11\ Annual costs are $106,425.
---------------------------------------------------------------------------

DPM record costs of Section 57.5075. \12\
---------------------------------------------------------------------------

\12\ Annual costs are $204.
---------------------------------------------------------------------------

Thus the yearly costs for small mines, amortized over 5 years at an
annual discount rate of 7.0 percent, would be $1,554,086, or an average
of $20,183 per mine. This is 0.82 percent of annual revenue, which is
below the threshold for a significant economic impact. This is not the
type of impact that would force a mine to close sooner rather than
later. The conclusion is that any closure impacts would be mild and
would occur foreseeably over time, rather than abruptly.

Compliance Assistance

The Agency plans to provide extensive compliance assistance to the
mining community. MSHA intends to focus these efforts on smaller metal
and nonmetal operators, including training them to measure DPM
concentrations, providing technical assistance on available controls,
and establishing a system for addressing compliance inquiries from
small businesses. The Agency will also issue a compliance guide,
continue its current efforts to disseminate educational materials and
software, and hold workshops to inform the mining community.
In conclusion, MSHA believes that it has taken all of the steps
consistent with the Mine Safety and Health Act that could substantially
reduce the impacts of this rule on small entities.

MSHA did explore a variety of alternatives in its Initial
Regulatory Flexibility Analysis. See 63 FR 58212. For example, it
looked at a regulatory approach that would have focused on limiting
workers exposure rather than limiting particulate concentration. Under
such an approach, operators would have been able to use administrative
controls and respiratory protection equipment to reduce diesel
particulate exposure. For the reasons explained in that Initial
Analysis, the Agency declined to take such an approach. For MSHA's
response to comments on the specific topics of administrative controls
and respiratory protection equipment, see Part IV's discussion of
57.5060(e) and 57.5060(f).

(D) Unfunded Mandates Reform Act of 1995

For purposes of the Unfunded Mandates Reform Act of 1995, the final
rule does not include any Federal mandate that may result in increased
expenditures by State, local, or tribal governments, or increased
expenditures by the private sector of more than $100 million.

(E) Paperwork Reduction Act of 1995

The final rule contains information collections which are subject
to review by the Office of Management and Budget (OMB) under the
Paperwork Reduction Act of 1995 (PRA95). The final rule will impose two
types of paperwork burden hours on underground M/NM mine operators that
use diesel powered equipment. First, there are burden hours that will
occur only in the first year the rule is in effect (hereafter known as
first year burden hours). Second, there are burden hours that will
occur every year that the rule is in effect, starting with the first
year (hereafter known as ``annual'' burden hours).
In the first year, mine operators will incur 3,571 burden hours and
associated burden costs of about $171,926. After the first year, mine
operators will incur 526 burden hours annually and associated costs of
about $21,871.
We have submitted a copy of this final rule to OMB for its review
and approval of these information collections. Interested persons are
requested to send comments regarding this information collection,
including suggestions for reducing this burden, to the Office of
Information and Regulatory Affairs, OMB New Executive Office Building,
725 17th St., NW, Rm. 10235, Washington, DC 20503, Attn: Desk Officer
for MSHA. Submit written comments on the information collection not
later than 60 days after date of publication in the Federal Register.
Our paperwork submission summarized above is explained in detail in
the REA. The REA includes the estimated costs and assumptions for each
final paperwork requirement related to this final rule. A copy of the
REA is available from us. These paperwork requirements have been
submitted to the Office of Management and Budget for review under
section 3504(h) of the Paperwork Reduction Act of 1995. Respondents are
not required to respond to any collection of information unless it
displays a current valid OMB control number.

(F) National Environmental Protection Act

The National Environmental Policy Act (NEPA) of 1969 requires each
Federal agency to consider the environmental effects of final actions
and to prepare an Environmental Impact Statement on major actions
significantly affecting the quality of the environment. MSHA has
reviewed the final rule in accordance with NEPA requirements (42 U.S.C.
4321 et. seq.), the regulations of the Council of Environmental Quality
(40 CFR Part 1500), and the Department of Labor's NEPA procedures (29
CFR Part 11). As a result of this review, MSHA has determined that this
rule will have no significant environmental impact.

(G) Executive Order 12360 Governmental Actions and Interference With
Constitutionally Protected Property Rights

This final rule is not subject to Executive Order 12360,
Governmental Actions and Interference with Constitutionally Protected
Property Rights, because it does not involve implementation of a policy
with takings implications.

(H) Executive Order 13045 Protection of Children From Environmental
Health Risks and Safety Risks

In accordance with Executive Order 13045, MSHA has evaluated the
environmental health and safety effects of the final rule on children.
The Agency has determined that the rule will not have an adverse impact
on children.

(I) Executive Order 12988 (Civil Justice)

The Agency has reviewed Executive Order 12988, Civil Justice
Reform, and determined that the final rule will not unduly burden the
Federal court system. The rule has been written so as to provide a
clear legal standard for affected conduct, and has been reviewed
carefully to eliminate drafting errors and ambiguities.

[[Page 5900]]

(J) Executive Order 13084 Consultation and Coordination With Indian
Tribal Governments

MSHA certifies that the final rule will not impose substantial
direct compliance costs on Indian tribal governments.

(K) Executive Order 13132 (Federalism)

MSHA has reviewed the final rule in accordance with Executive Order
13132 regarding federalism and has determined that it does not have
``federalism implications.'' The final rule does not ``have substantial
direct effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.''

VII. References

Abbey, David, et al., ``Ambient Air Pollution and Cancer in
California Seventh-day Adventists,'' Archives of Environmental
Health, 96(5):271-280, September/October 1991.
Ahlberg, J., et al., ``Cancer and Professional Drivers-A
Problem-Oriented Study of Records,'' Lakartidningen, 78(15):1545-
1546, 1981.
Ahlman, Kaj, et al., ``Mortality Among Sulfide Ore Miners,''
American Journal of Industrial Medicine, 19:603-617, 1991.
American Conference of Governmental Industrial Hygienists,
Diesel Exhaust (Particulate and Particulate Adsorbed Component)
September 20, 1998.
American Federation of Labor and Congress of Industrial
Organizations v. Occupational Safety and Health Administration, 965
F.2d 962 (11th Cir., 1992).
American Federation of Labor and Congress of Industrial
Organizations v. Peter J. Brennan, Secretary of Labor, 530 F.2d 109
(3rd Cir., 1975).
American Iron and Steel Institute et al., v. Occupational Safety
and Health Administration, 577 F.2d 825 (3rd Cir., 1978).
American Mining Congress, public comment submitted in response
to MSHA's January 5, 1992 ANPRM, #87-0-21,Executive Summary, page 1
and Appendix A, July 10, 1992.
American Textile Manufacturers Institute, Inc. et al., v.
Donovan, Secretary of Labor, et al., 452 U.S. 490, 101 S.Ct. 2478
(1981).
American Trucking Associations, Inc. et al., v. United States
Environmental Protection Agency, 175 F.3d 1027 (D.C. Cir. 1999).
American Trucking Associations, Inc. et al., v. United States
Environmental Protection Agency, No. 97-1440 and 97-1441
consolidated cases, June 28, 1999.
Ames, Richard G., et al., ``Chronic Respiratory Effects of
Exposure to Diesel Emissions in Coal Mines,'' Archives of
Environmental Health, 39(6):389-394, November/December 1984.
Ames, Richard G., et al., ``Does Coal Mine Dust Present a Risk
for Lung Cancer? A Case-Control Study of U.S. Coal Miners,''
Archives of Environmental Health, 38(6):331-333, November/December
1983.
Ames, Richard G., et al., ``Acute Respiratory Effects of
Exposure to Diesel Emissions in Coal Miners,'' American Review of
Respiratory Disease, 125:39-42, 1982.
Armstrong, B.K., et al., ``Mortality in Gold and Coal Miners in
Western Australia with Special Reference to Lung Cancer,'' British
Journal of Industrial Medicine, 36:199-205, 1979.
Attfield, M.D., et al., ``Exposure to Diesel Fumes and Dust at
Six Potash Mines,'' Annals of Occupational Hygiene, 26:817-831,
1982.
Attfield, M.D., ``The Effect of Exposure to Silica and Diesel
Exhaust in Underground Metal and Nonmetal Miners,'' in Proceedings
of an American Council of Governmental Industrial Hygienists Topical
Symposium: Industrial Hygiene for Mining and Tunneling, 1979.
Atuhaire, L.K., M.J. Campbell, A.L. Cochrane, M. Jones, F.
Moore, ``Mortality of Men in the Rhondda Fach 1950-80,'' British
Journal of Industrial Medicine, 42:741-745, 1985.
Bagley, Susan T., et al., ``Characterization of Fuel and
Aftertreatment Device Effects on Diesel Emissions,'' Health Effects
Institute, Research Report Number 76, September 1996.
Balarajan, R., and M.E. McDowall, ``Professional Drivers in
London: A Mortality Study,'' British Journal of Industrial Medicine,
45:483-486, 1988.
Baltimore Gas and Electric Co., et al., v. Natural Resources
Defense Council, 462 U.S. 87, 103 S.Ct. 2246, (1983).
Battigelli, M.C., ``Effects of Diesel Exhaust,'' Archives of
Environmental Health, 10:165-167, February 1965.
Battigelli, M.C., et al., ``Environmental and Clinical
Investigation of Workmen Exposed to Diesel Exhaust in Railroad
Engine Houses,'' Industrial Medicine and Surgery, 33:121-1243, 1964.
Becklake, M.R., ``Occupational Exposures and Chronic Airways
Disease,'' in Rom, W.R., Environmental and Occupational Medicine,
2nd Ed., Little Brown and Co., pp. 453-464,1992.
Becklake, M.R., ``Occupational Exposures: Evidence for a Causal
Association with Chronic Obstructive Pulmonary Disease,'' American
Review of Respiratory Disease, 140:S85-S91, 1989.
Belinsky, SA et al., Pulmonary Toxicity of Inhaled Diesel
Exhaust and Carbon Black in Chronically Exposed Rats. Part III:
Examination of Possible Target genes, HEI Report #68, Cambridge, MA
Health effects Institute, 1995.
Bender, Alan, et al., ``Minnesota Highway Maintenance Worker
Study: Cancer Mortality,'' American Journal of Industrial Medicine,
15:545-556, 1989.
Benhamou, Simone, et al., ``Occupational Risk Factors of Lung
Cancer in a French Case-Control Study,'' British Journal of
Industrial Medicine, 45:231-233, 1988.
Bhatia, Rajiv, et al., ``Diesel Exhaust Exposure and Lung
Cancer,'' Journal of Epidemiology, 9:84-91, January 1998.
Birch, M.E. and R.A. Cary, ``Elemental Carbon-Based Method for
Monitoring Occupational Exposures to Particulate Diesel Exhaust,''
Aerosol Science and Technology, 25:221-241, 1996.
Boffetta, Paolo, et al., ``Diesel Exhaust Exposure and Mortality
Among Males in the American Cancer Society Prospective Study,''
American Journal of Industrial Medicine, 14:403-415, 1988.
Bond, J.A., et al., ``The Role of DNA Adducts in Diesel Exhaust-
Induced Pulmonary Carcinogenesis,'' in Mendelsohn, J.L. and R.J.,
Albertini, eds., Mutation and the Environment Part C: Somatic and
Heritable Mutation, Adduction, and Epidemiology, Wiley-Liss, pp.
259-269, 1990.
Bond J. A., et al. (1990 b) ``Concentration- and time-dependent
formation of DNA adducts in lungs of rats exposed to diesel
exhaust.'' Toxicology 60:127-135.
Bowen, Otis R., Secretary of Heath and Human Services v.
American Hospital Association, et al., 476 U.S. 610, 106 S.Ct. 2101
(1986).
Brightwell, J., et al., ``Neoplastic and Functional Changes in
Rodents After Chronic Inhalation of Engine Exhaust Emissions,''
Elsevier Science Publisher B.V. (Biomedical Division), Carcinogenic
and Mutagenic Effects of Diesel Engine Exhaust, pp. 471-485, 1986.
Brooks, A.L., et al., ``Biological Availability of Mutagenic
ChemicalsAssociated with Diesel Exhaust Particles,'' in Health
Effects of Diesel Engine Emissions (Pepelko, W. E., R.M. Danner,
N.A. Clarke, eds.) pp. 345-358, EPA/600/9-80/57a, U.S. Environmental
Protection Agency, Cincinnati, OH, 1980.
Bruske-Hohlfeld, I. et al., ``Lung Cancer Risk in Male Workers
Occupationally Exposed to Diesel Motor Emissions in Germany,''
American Journal of Industrial Medicine, 36:405-414, 1999.
Buiatti, E., et al., ``A Case Control Study of Lung Cancer in
Florence, Italy. I Occupational Risk Factors,'' Journal of
Epidemiology and Community Health, 39:244-250, 1985.
Burns, Patricia, and G. Marie Swanson, ``The Occupational Cancer
Incidence Surveillance Study (OCISS): Risk of Lung Cancer by Usual
Occupation and Industry in the Detroit Metropolitan Area,'' American
Journal of Industrial Medicine, 19:655-671, 1991.
Busby, William F. and Paul M. Newberne, ``Diesel Emissions and
Other Substances with Animal Carcinogenicity,'' in Diesel Exhaust: A
Critical Analysis of Emissions, Exposure, and Health Effects, Health
Effects Institute, Cambridge, MA, pp. 187-220, 1995.
California Environmental Protection Agency, Health and Safety
Code, California Air Pollution Control Laws, Division 26, Air
Resources, Section 39655.
Canada Centre for Mineral and Energy Technology (CANMET),
``Diesel Emissions Exposure Reduction in Mines,'' by Don Dainty,
Canadian Ad hoc Diesel Committee Proceedings of the DEEP Conference,
Toronto, Ontario, November 6-7, 1996.
Cantrell, Bruce et al., ``Pollutant Levels in Underground Coal
Mines Using Diesel Equipment,'' Proceedings of the 6th U.S. Mine
Ventilation Symposium, Salt Lake City, UT, 1993.
Cantrell, Bruce and Kenneth Rubow, ``Measurement of Diesel
Exhaust Aerosol In

[[Page 5901]]

Underground Coal Mines'' U.S. Bureau of Mines Information Circular
9324, pp. 11-17, 1992.
Cantrell, Bruce and Kenneth Rubow, ``Diesel Exhaust Aerosol
Measurements In Underground Metal and Nonmetal Mines,'' U.S. Bureau
of Mines Information Circular 9324, pp. 18-23, 1992.
Cass, G.R., and H.A. Gray, ``Regional Emissions and Atmospheric
Concentrations of Diesel Engine Particulate Matter: Los Angeles as a
Case Study,'' in Diesel Exhaust: A Critical Analysis of Emissions,
Exposure, and Health Effects, pp. 127-137, Health Effects Institute,
Cambridge, MA, 1995.
Castranova, V., et al., ``The Response of Rat Alveolar
Macrophages to Chronic Inhalation of Coal Dust and/or Diesel
Exhaust,'' Environmental Research, 36:405-419, 1985.
Centers for Disease Control, Mine Health Research Advisory
Committee Diesel Subgroup and X-Ray Surveillance Subgroup; Open
Meetings; 49 FR 37174, September 21, 1984.
Christie et al. (1995), Mortality in the New South Wales Coal
Industry, 1973-1992, Medical Journal of Australia 163:19-21.
Citizens to Preserve Overton Park, Inc., et al., v. John A.
Volpe, Secretary, Department of Transportation, et al., 401 U.S.
402,91 S.Ct. 814 (1971).
Clean Air Act Amendments of 1990, January 23, 1990.
Clean Air Scientific Advisory Committee, ``Review of EPA's
Health Assessment Document for Diesel Emissions, (EPA 600/8-90/
057D),'' February 2000.
Coggon, David, et al., ``Use of Job-Exposure Matrix in an
Occupational Analysis of Lung and Bladder Cancers on the Basis of
Death Certificates,'' Journal of the National Cancer Institute,
72(1):61-65, January 1984.
Cohen, A.J. and M.W.P. Higgins, ``Health Effects of Diesel
Exhaust: Epidemiology,'' in Diesel Exhaust: A Critical Analysis of
Emissions, Exposures, and Health Effects, Health Effects Institute,
Cambridge, MA, pp. 251-292, 1995.
Correa, P., et al., ``The Causes of Lung Cancer in Louisiana,''
in Mizell, M. and Correa, P. (eds.) Lung Cancer: Causes and
Prevention, Deerfield Beach: Verlag Cheine International, pp. 73-82,
1984.
Costello, J., et al., ``Mortality from Lung Cancer in U.S. Coal
Miners, American Journal of Public Health, 64(3):222-224, 1974.
Cox, L.A., ``Does Diesel Exhaust Cause Human Lung Cancer,'' Risk
Analysis, 17(6):807-829, December 1997.
Crump, KS (1999) Lung cancer mortality and diesel exhaust:
Reanalysis of a retrospective cohort study of U.S. railroad workers.
Inhalation Toxicology 11:101-107.
DCL International Inc., ``Mine-X Sootfilters,'' Operation and
Maintenance Guide, Toronto, Ontario, Canada.
Dahmann, Dirk, et al., ``Diesel Engine Emissions in Workplace-
Atmospheres in Germany,'' Occupational Hygiene, 3:255-262, 1996.
Damber, L. and L.G. Larsson, ``Professional Driving, Smoking,
and Lung Cancer: A Case Referent Study,'' British Journal of
Industrial Medicine, 42:246-252, 1985.
Dawson, S.V., et al., ``Health Risk Assessment for Diesel
Exhaust,'' (public and SRP review draft) California Environmental
Protection Agency, Air Resources Board, Office of Environmental
Health Assessment, February 23, 1998.
DeCoufle, Pierre, et al., ``A Retrospective Survey of Cancer in
Relation to Occupation,'' NIOSH Research Report, DHEW, (NIOSH)
Publication No. 77-178, 1977.
Diaz-Sanchez, D., ``The Role of Diesel Exhaust Particles and
Their Associated Polyaromatic Hydrocarbons in the Induction of
Allergic Airway Disease,'' Allergy, 52:52-56, 1997.
Diaz-Sanchez, D., et al., ``Combined Diesel Exhaust Particle and
Ragweed Allergen Challenge Markedly Enhances Human In Vivo Nasal
Ragweed-Specific IgE and Skews Cytokine Production to a T Helper
Cell 2-Type Pattern,'' Journal of Immunology, 158:2406-2413, 1997.
Diaz-Sanchez, D., et al., ``Enhanced Nasal Cytokine Production
in Human Beings After In Vivo Challenge with Diesel Exhaust
Particles,'' Journal of Allergy Clinical Immunology, 98:114-123,
1996.
Diaz-Sanchez, D., et al., ``Diesel Exhaust Particles Induce
Local IgE Production in Vivo and Alter the Pattern of IgE Messenger
RNA Isoforms,'' Journal of Clinical Investigation, 94(4):1417-1425,
1994.
Diesel Emission Control-Sulfur Effects (DECSE) Program, Phase 1
Interim Data Report No. 4: Diesel Particulate Filters-Final Report,
(Sponsored by the U.S. Department of Energy, Engine Manufacturers
Association, Manufacturers of Emission Controls Association),
January 2000.
Dockery, Douglas, et al., ``An Association Between Air Pollution
and Mortality in Six U.S. Cities,'' New England Journal of Medicine,
24:1753-1759, 1993.
Dubrow, Robert, and David Wegman, ``Cancer and Occupation in
Massachusetts: A Death Certificate Study,'' American Journal of
Industrial Medicine, 6:207-230, 1984.
Dusseldorp, A., et al., ``Association of PM10 and
Airborne Iron with Respiratory Health of Adults Living Near a Steel
Factory,'' American Journal of Respiratory and Critical Care
Medicine, 152:1932-1939,1995.
Edling, Christer, et al., ``Mortality Among Personnel Exposed to
Diesel Exhaust,'' International Archives of Occupational and
Environmental Health, 59:559-565, 1987.
Ellington, Ray, Public Testimony, presented at the ``Workshop on
Miners'' Exposure to Diesel Particulate,'' Salt Lake City, Utah,
October 12-13, 1995.
Emmelin, Anders, et al., ``Diesel Exhaust Exposure and Smoking:
A Case Referent Study of Lung Cancer Among Swedish Dock Workers,''
Journal of Epidemiology, 4:237-244, 1993.
Engine Manufacturers Association v. EPA, 88 F.3d 1075, 319 U.S.
App.D.C. 12 (1996).
Enterline, P.E., ``A Review of Mortality Data for American Coal
Miners,'' Annals New York Academy of Sciences, 200:260-272, 1972.
Enya, Takeji, et al., ``3 Nitrobenzanthrone, a Powerful
Bacterial Mutagen and Suspected Human Carcinogen Found in Diesel
Exhaust and Airborne Particulates,'' Environmental Science and
Technology, 31:2772-2776, 1997.
EPA, Health Assessment Document for Diesel Emissions, Office of
Research and Development, SAB Review Draft, EPA-600/8-90/057D,
November 1999.
EPA, Air Pollution; Tier 2 Motor Vehicle Emission Standards and
Gasoline Sulphur Control Requirements; Diesel Fuel Quality Control;
Proposed Rule, 40 CFR Parts 80, 85 and 86, 64 FR 26003, May 13,
1999.
EPA, Control of Air Pollution from New Motor Vehicles;
Compliance Programs for New Light-Duty Vehicles and Light-Duty
Trucks; Final Rule, 40 CFR Part 9 et al., 64 FR 23906, May 4, 1999.
EPA, Control of Emissions of Air Pollution From Nonroad Diesel
Engines; Final Rule, 40 CFR Parts 9, 86, and 89, October 23, 1998.
EPA, Emission Standards for Locomotives and Locomotive Engines;
Final Rule, 40 CFR Parts 85, 89, and 92, 63 FR 18978, April 16,
1998.
EPA, 40 CFR Part 86, Control of Air Pollution from New and In-
Use Motor Vehicles and New and In-Use Motor Vehicle Engines:
Certification and Test Procedures.
EPA, 40 CFR Part 85, Control of Air Pollution from Motor
Vehicles and Motor Vehicle Engines.
EPA, 40 CFR Part 80, Regulation of Fuels and Fuel Additives.
EPA, Control of Emissions of Air Pollution from Highway Heavy-
Duty Engines; Final Rule, 62 FR 54693, 40 CFR Parts 9 and 86,
October 21, 1997.
EPA, Control of Emissions of Air Pollution from Nonroad Diesel
Engines; Proposed Rule, 40 CFR Parts 9, 86, and 89, 62 FR 50151,
September 24, 1997.
EPA, National Ambient Air Quality Standards for Particulate
Matter, Final Rule, 40 CFR Part 50, 62 FR 38651, July 18, 1997.
EPA, Office of Air & Radiation, Office of Air Quality Planning &
Standards, Fact Sheet, EPA's Revised Particulate Matter Standards,
July 17, 1997.
EPA, ``PM-2.5 Composition and Sources,'' Office of Air Quality
Planning and Standards, June 16, 1997.
EPA, Emission Standards for Locomotives and Locomotive Engines;
Proposed Rule, 40 CFR Parts 85, 89, and 92, 62 FR 6366, February 11,
1997.
EPA, Environmental Fact Sheet, ``Statement of Principles for
Nonroad Diesel Engines,'' EPA 420-F-96-015, September 1996.
EPA, Fact Sheet, ``Emission Control Potential for Heavy-Duty
Diesel Engines,'' EPA 420-F-95-009(b), 1996.
EPA, Review of the National Ambient Air Quality Standards for
Particulate Matter: Policy Assessment of Scientific and Technical
Information, OAQPS Staff Paper, EPA-452/R-96-013, July 1996.
EPA, Control of Emissions of Air Pollution from Highway Heavy-
Duty Engines, Proposed Rule, 40 CFR Part 86, 61 FR 33421, June 27,
1996.
EPA, Air Quality Criteria for Particulate Matter, Volumes I-III,
EPA/600/P-95/001aF/001bF/001cF, April 1996.
EPA, Determination of Significance for Nonroad Sources and
Emission Standards for New Nonroad Compression-Ignition Engine At or
Above 37 Kilowatts; Final Rule, 40 CFR Parts 9 and 89, 59 FR 31306,
June 17, 1994.
EPA, Fuels and Fuel Additives Registration Regulations, Final
Rule, 40 CFR Part 79, 59 FR 33042, June 27, 1994.

[[Page 5902]]

EPA, The Plain English Guide to the Clean Air Act, EPA 400-K-93-
001, April 1993.
EPA, Control of Air Pollution From New Motor Vehicles and New
Motor Vehicle Engines: Gaseous and Particulate Emission Regulations
for 1994 and Later Model Year Light-Duty Vehicles and Light-Duty
Trucks; Final Rule, 40 CFR Part 86, 56 FR 25724, June 5, 1991.
EPA, Control of Air Pollution From New Motor Vehicles and New
Motor Vehicle Engines and Fuel Economy of Motor Vehicles: Emissions
Certification and Test Procedures, Fuel Economy Test Procedures:
Technical Amendments; Final Rule, Parts 86 and 600, 40 CFR 86.088-
11, Emission Standards for 1988 and Later Model Year Diesel Heavy-
Duty Engines, 52 FR 47853, December 16, 1987.
EPA, Second Addendum to Air Quality Criteria for Particulate
Matter and Sulfur Oxides (1982): Assessment of Newly Available
Health Effects Information, EPA Report No. EPA-600/8-86-020F,
December 1986.
EPA, Control of Air Pollution From New Motor Vehicles and New
Motor Vehicle Engines; Final Rule, 40 CFR 86.085-11, Part 86,
Emission Standards for 1984 and Later Model Year Diesel Heavy-Duty
Engines, 48 FR 52183, November 16, 1983.
Federal Institute for Occupational Safety and Health, ``Cohort
Study on the Effect of Diesel Motor Emission on Lung Cancer
Mortality in Potash Mining,'' Unpublished Cohort Study in German,
NIH Library Translation, NIH-98-120.
Financial Times, ``Survey of World Motor Industry (2),'' March
5, 1996.
Firket, J., ``Fog Along the Meuse Valley,'' Transactions of the
Faraday Society, 32:1192-1197, 1931.
French, Ian W., ``An Annotated Bibliography Relative to the
Health Implications of Exposure of Underground Mine Workers to
Diesel Exhaust Emissions (Contract 16SQ.23440-6-9095),'' Report to
the Department of Energy, Mines and Resources, Ottawa, Canada, Dec.
11, 1978.
Fritz, Steven G., ``Exhaust Emissions from a Caterpillar 3306
PCNA Mining Engine Equipped with a Jeffrey Exhaust Filter System,''
Southwest Research Institute, Final Report, prepared for MSHA,
February 2000.
Gallagher, J., et al., ``Formation of DNA Adducts in Rat Lung
Following Chronic Inhalation of Diesel Emissions, Carbon Black and
Titanium Dioxide Particles,'' Carcinogenesis, 15(7):1291-1299, 1994.
Gamble, John, et al., Epidemiological-Environmental Study of
Diesel Bus Garage Workers: Acute Effects of NO2 and
Respirable Particulate on the Respiratory System,'' Environmental
Research, 42:201-214, 1987(a).
Gamble, John, et al., ``Epidemiological-Environmental Study of
Diesel Bus Garage Workers: Chronic Effects of Diesel Exhaust on the
Respiratory System,'' Environmental Research, 44:6-17, 1987(b).
Gamble, John, and William Jones, ``Respiratory Effects of Diesel
Exhaust in Salt Miners,'' American Review of Respiratory Disease,
128:369-394, 1983.
Gamble, John, et al., ``Acute Changes in Pulmonary Function in
Salt Miners,'' in Proceedings of an American Council of Governmental
Industrial Hygienist Topical Symposium: Industrial Hygiene for
Mining and Tunneling, Denver, CO, November 6-7, 1978.
Gangel, M.K. and E.D. Dainty, ``Ambient Measurement of Diesel
Particulate Matter and Respirable Combustible Dust in Canadian
Mines,'' Proceedings of the 6th U.S. Mine Ventilation Symposium
(Bhaskar, R., ed.) pp. 83-89, Society for Mining, Metallurgy, and
Exploration, Littleton, CO., 1993.
Garshick, Eric, M.D., letter to U.S. EPA, August 15, 1991.
Garshick, Eric, et al., ``A Retrospective Cohort Study of Lung
Cancer and Diesel Exhaust Exposure in Railroad Workers,'' American
Review of Respiratory Disease, 137:820-825, 1988.
Garshick, Eric, et al., ``A Case-Control Study of Lung Cancer
and Diesel Exhaust Exposure in Railroad Workers,'' American Review
of Respiratory Disease, 135:1242-1248, 1987.
Gautam, Mridul, Public Testimony, presented at the ``Workshop on
Miners' Exposure to Diesel Particulate,'' Beckley, West Virginia,
September 12-13, 1995.
Glenn, R., et al., ``Respiratory health effects in relation to
underground diesel use,'' Proceeding of VI International
Pneumoconiosis Conference, 1983.
Green, Gareth M. and Ann Y. Watson, ``Relation Between Exposure
to Diesel Emissions and Dose to the Lung,'' in Diesel Exhaust: A
Critical Analysis of Emissions, Exposure, and Health Effects, Health
Effects Institute, pp. 167-184, Cambridge, MA, 1995.
Gu, Zu-Wei, et al., Induction of Unscheduled DNA Synthesis in
V79 Cells by Diesel Emission Particles Dispersed in Simulated
Pulmonary Surfactant, Division of Respiratory Disease Studies,
NIOSH, Morgantown, West Virginia, 1991.
Gu, Zu-Wei, et al., ``Micronucleus Induction and Phagocytosis in
Mammalian Cells Treated with Diesel Emission Particles,'' Mutation
Research, 279:55-60, 1992.
Guberan, E., et al., ``Increased Risk for Lung Cancer and for
Cancer of the Gastrointestinal Tract Among Geneva Professional
Drivers,'' British Journal of Industrial Medicine, 49:337-344, 1992.
Gushee, David, ``Heavy Duty Diesel Engines and Their Fuel: Can
They Survive Clean Air Regulations?'' Congressional Reference
Service, The Library of Congress, 95-961 ENR, September 11, 1995.
Gustafsson, Lennart, et al., ``Mortality and Cancer Incidence
Among Swedish Dock Workers--A Retrospective Cohort Study,''
Scandinavian Journal of Work, Environment and Health, 12:22-26,
1986.
Gustavsson, Per, et al., ``Lung Cancer and Exposure to Diesel
Exhaust Among Bus Garage Workers,'' Scandinavian Journal of Work,
Environment and Health, 16:348-354, 1990.
Hahon, Nicholas, et al., ``Influenza Virus Infection in Mice
after Exposure to Coal Dust and Diesel Engine Emissions,''
Environmental Research, 37:44-60, 1985.
Hall, Nancy, and Ernst Wynder, ``Diesel Exhaust Exposure and
Lung Cancer: A Case-Control Study,'' Environmental Research, 34:77-
86, 1984.
Haney, Robert, and Saseen, George, ``Estimation of Diesel
Particulate Concentrations in Underground Mines,'' Mining
Engineering, Volume 52, Number 5, April 2000.
Haney, Robert, George Saseen, and Robert Waytulonis, ``An
Overview of Diesel Particulate Control Technology in the U.S. Mining
Industry,'' Appl. Occup. Environ. Hyg., (12)12, December 1997.
Haney, Robert, ``Diesel Particulate Exposures in Underground
Mines,'' Mining Engineering, 173:176, February 1992.
Hansen, Eva S., ``A Follow-up Study on the Mortality of Truck
Drivers,'' American Journal of Industrial Medicine, 23:811-821,
1993.
Harris, Jeffrey E., ``Diesel Emissions and Lung Cancer,''
Society for Risk Analysis, Vol. 3, No. 2, 1983.
Hattis, Dale, and Silver, Ken, ``Projection of Human Lung Cancer
Risks for Diesel Particulates from Animal Data--Effects of Using
Measures of Internal vs External Dose, and Possible Interactions
with Smoking,'' Submitted by CENTED University, in response to
ANPRM, #87-0-18, May 20, 1992.
Hayes, Richard, et al., ``Lung Cancer in Motor Exhaust-Related
Occupations,'' American Journal of Industrial Medicine, 16:685-695,
1989.
Health Effects Institute, ``Diesel Emissions and Lung Cancer:
Epidemiology and Quantitative Risk Assessment,'' A Special Report of
the Institute's Diesel Epidemiology Expert Panel, June 1999.
Heinrich, Uwe, et al., ``Chronic Inhalation Exposure of Wistar
Rats and Two Different Strains of Mice to Diesel Engine Exhaust,
Carbon Black, and Titanium Dioxide,'' Inhalation Toxicology, 7:533-
556, 1995.
Heinrich, Uwe, ``Carcinogenic Effects of Solid Particles,''
1994.
Heinrich, Uwe, et al., ``Inhalation Exposure of Rats to Tar/
Pitch Condensation Aerosol or Carbon Black Alone or in Combination
with Irritant Gases,'' 1994.
Heinrich, Uwe, et al., ``Chronic Effects on the Respiratory
Tract of Hamsters, Mice and Rats after Long-term Inhalation of High
Concentrations of Filtered and Unfiltered Diesel Engine Emissions,''
Journal of Applied Toxicology, (6)6:383-395, 1986.
Hemminki, Kari, et al., ``DNA Adducts Among Personnel Servicing
and Loading Diesel Vehicles,'' Carcinogenesis, 15(4):767-769, 1994.
Hodgson, J.T. and R.D. Jones, ``A Mortality Study of Carbon
Black Workers Employed at Five United Kingdom Factories Between 1947
and 1980,'' Archives of Environmental Health, 40(5):261-268,
September/October 1985.
Holtz, John, Safety with Mobile Diesel-Powered Equipment
Underground, United States Department of Interior, Bureau of Mines,
Report of Investigations No. 5616, 1960.
Hou, S.M., et al., ``Relationship between hprt mutant frequency,
aromatic DNA adducts and genotypes for GSTM1 and NAT2 in bus
maintenance workers,'' Carcinogenesis, 16:1913-1917, 1995.
Howe, Geoffrey R., et al., ``Cancer Mortality (1965-77) in
Relation to Diesel Fume and

[[Page 5903]]

Coal Exposure in a Cohort of Retired Railway Workers,'' Journal of
the National Cancer Institute, Vol. 70, No. 6, June 1983.
Hricko, Andrea, Deputy Assistant Secretary for MSHA, ``Workshop
on Diesel Exhaust: Considerations in the Use of Epidemiologic Data
for Quantitative Cancer Risk Assessments,'' San Francisco,
California, January 29, 1996.
Inco Limited, public comment submitted in response to MSHA's
January 1992 ANPRM, 87-0-5, April 16, 1992.
Industrial Union Department, AFL-CIO v. American Petroleum
Institute et al., No. 78-911, 448 U.S. 607, 100 S.Ct. 2844 (1980).
Industrial Union Department, AFL-CIO v. James D. Hodgson, 499
F.2d 467 (1974).
Ichinose, Takamichi, et al., ``Murine Strain Differences in
Allergic Airway Inflammation and Immunoglobulin Production by a
Combination of Antigen and Diesel Exhaust Particles,'' Toxicology,
122:183-192, 1997a.
Ichinose, et al., ``Lung Carcinogenesis and Formation of in Mice
by Diesel Exhaust Particles'' Carcinogenesis, 18:185-192, 1997b.
Interagency Task Group Report (MSHA, NIOSH, BOM) ``The Health
and Safety Implications of the Use of Diesel-Powered Equipment in
Underground Coal Mines,'' 1986.
International Agency for Research on Cancer, ``Diesel and
Gasoline Engine Exhausts,'' in: IARC Monographs on the Evaluation of
the Carcinogenic Risk of Chemicals to Humans, Vol. 46, Lyon, France,
1989(b).
International Agency for Research on Cancer, ``Printing
Processes and Printing Inks, Carbon Black and some Nitro
Compounds,'' IARC Monographs on the Evaluation of the Carcinogenic
Risk of Chemicals to Human, Volume 65.
International Ladies' Garment Workers' Union, et al., v. Raymond
J. Donovan, et al., 722 F.2d 795, 232 U.S. App. D.C. 309 (1983).
International Programme on Chemical Safety, Environmental Health
Criteria 171, Diesel Fuel and Exhaust Emissions, World Health
Organization, Geneva, 1996.
International Union, United Mine Workers of America v. Cynthia
Metzler et al., U.S. D.C. Circuit Court of Appeals, #97-1109,
February 1997.
Iwai, Kazuro, et al., ``Long-Term Inhalation Studies of Diesel
Exhaust on F344 SPF Rats. Incidence of Lung Cancer and Lymphoma'' in
Carcinogenic and Mutagenic Effects of Diesel Exhaust, Elsevier
Science B.V. (Biomedical Division), 1986.
Jacobsen, Michael, et al., Respiratory Infections in Coal Miners
Exposed to Nitrogen Oxides, Health Effects Institute Research Report
18, 1988.
Johnston, A.M, et al. (1997), Investigation of the possible
association between exposure to diesel exhaust particulates in
British coal mines and lung cancer. Institute of Occupational
Medicine (IOM), Report TM/97/08 (Edinburgh, Scotland).
Jorgenson, Harold, and Ake Svensson, ``Studies on Pulmonary
Function and Respiratory Tract Symptoms of Workers in an Iron Ore
Mine Where Diesel Trucks are Used Underground,'' Journal of
Occupational Medicine, Volume 12, No. 9, September 1970.
Kahn, Geralynn, et al., ``Acute Overexposure to Diesel Exhaust:
Report of 13 Cases,'' American Journal of Industrial Medicine,
13:405-406, 1988.
Kaplan, Isadore, ``Relationship of Noxious Gases to Carcinoma of
the Lung in Railroad Workers,'' Journal of the American Medical
Association, Vol. 171, No. 15, 1959.
Keane, M.J., et al., ``Genotoxicity of Diesel-Exhaust Particles
Dispersed in Simulated Pulmonary Surfactant,'' Mutation Research,
260:233-238, 1991.
King, Leon, et al., ``Evaluation of the Release of Mutagens from
Diesel Particles in the Presence of Physiological Fluids,''
Environmental Mutagenesis, 3:109-121, 1981.
Kittleson and Khalek, 1999.
Kuempel, E.D., L.T. Stayner, M.D. Attfield, C.R. Buncher,
``Exposure-Response Analysis of Mortality Among Coal Miners in the
United States,'' American Journal of Medicine, 28:167-184, 1995.
Lambert, B., et al., ``Analysis of Mutation at the hprt Locus in
Human T Lymphocytes,'' Toxicology Letters, 82-83:323-333, 1995.
Lerchen, Mary, et al., ``Lung Cancer and Occupation in New
Mexico,'' Journal of the National Cancer Institute, 79(4):639-645,
October 1987.
Leupker, Russell, and Michelle Smith, ``Mortality in Unionized
Truck Drivers,'' Journal of Occupational Medicine, Vol. 20, No. 10,
October 1978.
Levin, L.I., et al., ``Occupation and Lung Cancer in Shanghai: A
Case-Control Study,'' British Journal of Industrial Medicine,
45:450-458, 1988.
Liddell, F.D.K., ``Mortality of British Coal Miners in 1961,''
British Journal of Industrial Medicine, 30:15-24, 1973.
Lindsay, Joan, et al., ``The Canadian Labour Force Ten Percent
Sample Study: Cancer Mortality Among Men, 1965-1979,'' Journal of
Occupational and Environmental Medicine, Vol. 35, No. 4, 1993.
Lipsett, M. and G. Alexeeff, ``Quantitative Meta-Analysis on the
Relationship of Occupational Exposure to Diesel Exhaust and Lung
Cancer,'' Appendix C of Health Risk Assessment for Diesel Exhaust,
(public and SRP review draft) California Environmental Protection
Agency, Air Resources Board, Office of Environmental Health
Assessment, February 23, 1998.
Lipsett M., and Campleman, Susan, ``Occupational Exposure to
Diesel Exhaust and Lung Cancer: A Meta-Analysis,'' American Journal
of Public Health, (89) 1009-1017, July 1999.
Lovik, Martinus, et al., ``Diesel Exhaust Particles and Carbon
Black Have Adjuvant Activity on the Local Lymph Node Response and
Systemic IgE Production to Ovalbumin,'' Toxicology, 121:165-178,
1997.
Majewski, W. Addy, ``The Nature of Diesel Nanoparticles May
Require Rethinking of Particulate Matter Standards,'' Diesel
Progress, pp. 106-109, June 1998.
Martin, A.E., ``Mortality and Morbidity Statistics and Air
Pollution,'' Proceedings of the Royal Society of Medicine, 57:969-
975, 1964.
Marrecau, Willy, and Peter Klaus, ``Diesel Wire Mesh Particulate
Filter'' presentation at the Mining Emission Diesel Conference,
Toronto, Ontario, Canada, November 3-4, 1999.
Mayer, Ing, A., et al., ``Verified Particulate Trap Systems for
Diesel Engines-Filter List,'' Swiss Agency for the Environment,
Forests and Landscape, Version 1, August 1999.
Mayer, Ing, A., et al., ``Effectiveness of Particulate Traps on
Construction Site Engines: VERT Final Measurements,'' DieselNet
Technical Report, March 1999.
Mayer, Ing, A., ``VERT: Curtailing Emissions of Diesel Engines
in Tunnel Sites,'' April 1998.
Mauderly JL, et al., Diesel Exhaust is not a pulmonary
carcinogen in CD-1 mice exposed under conditions carcinogenic to
F344 rats. Fundam Appl Toxicol 1996; 30:233-242.
Mauderly, Joe L., et al., ``Pulmonary Toxicity of Inhaled Diesel
Exhaust and Carbon Black in Chronically Exposed Rats, Part I,
Neoplastic and Nonneoplastic Lung Lesions,'' Research Report Number
68, Health Effects Institute, Cambridge, MA, October 1994.
Mauderly, Joe L., ``Toxicological and Epidemiological Evidence
for Health Risks from Inhaled Engine Emissions,'' presented at the
Risk Assessment of Urban Air; Emissions, Exposure, Risk
Identification and Risk Quantification Conference held in Stockholm,
Sweden, May 31-June 5, 1992.
Mauderly, Joe L., ``Diesel Exhaust,'' Environmental Toxicants:
Human Exposures and Their Health Effects, Chapter 5, 1992.
McAteer, J. Davitt, Assistant Secretary for Mine Safety and
Health, MSHA, Letter to Diesel Particulate Workshop Participants,
July 24, 1995.
McElroy, G.E., ``Engineering Factors in the Ventilation of Metal
Mines,'' U.S. Department of the Interior, Bureau of Mines, Bulletin
385, 1935.
McKinnon, Dale, Public Testimony, presented at the ``Workshop on
Miners' Exposure to Diesel Particulate,'' Beckley, West Virginia,
September 12-13, 1995.
Menck, Herman, and Brian Henderson, ``Occupational Differences
in Rates of Lung Cancer,'' Journal of Occupational Medicine, Vol.18,
No. 12, December 1976.
Miller, B.G., and M. Jacobsen, ``Dust Exposure, Pneumoconiosis,
and Mortality of Coal Miners,'' British Journal of Industrial
Medicine, 42:723-733, 1985.
Milne, K.L., et al., ``Lung Cancer and Occupation in Alameda
County: A Death Certificate Case-Control Study,'' American Journal
of Industrial Medicine, 4:565-575, 1983.
Morabia, A., et al., ``Lung Cancer and Occupation: Results of a
Multicentre Case-Control Study,'' British Journal of Industrial
Medicine, 49:721-727, 1992.
Morfeld, P., K. Lampert, H. Ziegler, C. Stegmaier, G. Dhom, C.
Piekarski, ``Overall Mortality and Cancer Mortality of Coal Miners:
Attempts to Adjust for Healthy Worker Selection Effects,'' Annals of
Occupational Hygiene, 41(Supplement 1):346-351, 1997.
Morgan, W.K.C., ``Health Effects of Diesel Emissions,'' Annals
of Occupational Hygiene, 41(6):643-658, December 1997.
Mori, Y., et al., ``Inhibition of Catalase Activity in Vitro by
Diesel Exhaust

[[Page 5904]]

Particles,'' Journal of Toxicology and Environmental Health,
47(2):125-134, 1996.
Morton International, public comment submitted in response to
MSHA's January 1992 ANPRM, 87-0-11, July 10, 1992.
Motor Vehicle Manufacturers Association of the United States,
Inc., v. State Farm Mutual Automobile Insurance Company et al., 463
U.S. 29, 103 S.Ct. 2856 (1983).
MSHA, Results of Tests to Determine Interference on Diesel
Particulate Matter Measurements from Carbonate Dust, May 19, 2000.
MSHA, Results of Tests to Determine Interference on Diesel
Particulate Matter Measurements from Cigarette Smoke, March 14,
2000.
MSHA, Jackleg Drill Diesel Particulate Evaluation Carlin Mine,
Newmont Mining Corporation, (Mine I.D. No. 26 02271, Carlin,
Nevada), March 15, 2000.
MSHA, Sampling for Diesel Particulate Interferences Barrick
Goldstrike Mines, Incorporated, (Mine I.D. No. 26 01089, Elko,
Nevada), March 15, 2000.
MSHA, ``Diesel Particulate Evaluation at a Crusher and Sample
Preparation Room South Area, Newmont Mining Corporation, (Mine I.D.
No. 26 00500, Carlin, Nevada), March 15, 2000.
MSHA, Diesel Particulate Study at the Homestake Mine, Homestake
Mining Company, (Mine I.D. No. 39 00055, Lead, South Dakota), March
15, 2000.
MSHA, Sampling Results of the Diesel Particulate Study Conducted
at the Viburnum #28 Mine, The Doe Run Company, (Mine I.D. No. 23-
00494), Viburnum, Missouri, October 24, 1997.
MSHA, Sampling Results of the Diesel Particulate Study Conducted
at the Plattville Galena Mine, Conco, Western Stone Company, (Mine
I.D. No. 11-02931), North Aurora, Illinois, May 20, 1997.
MSHA, Sampling Results of the Diesel Particulate Study Conducted
at the Cleveland Mine, AKZO Nobel Salt, Inc., (Mine I.D. 33-01994),
Cleveland, Ohio, May 7, 1997.
MSHA, Health Standards for Occupational Noise Exposure in Coal,
Metal and Nonmetal Mines; Proposed Rule, 30 CFR Parts 56, 57, 62, 70
and 71, 61 FR 66348, December 17, 1996.
MSHA, Approval, Exhaust Gas Monitoring, and Safety Requirements
for the Use of Diesel-Powered Equipment in Underground Coal Mines;
Final Rule, 30 CFR Parts 7, et al., 61 FR 55412, October 25, 1996.
MSHA, Division of Mining Information Systems, Coal 1996-Size
Group Report, MSHA/DMIS, CM-441, (Quarters 1-4, 1996).
MSHA, ``Workshop on Miners' Exposure to Diesel Particulate,''
Transcript, Salt Lake City, Utah, October 12-13, 1995.
MSHA, ``Workshop on Miners' Exposure to Diesel Particulate,''
Transcript, Mt. Vernon, Illinois, October 6, 1995.
MSHA, ``Workshop on Miners' Exposure to Diesel Particulate,''
Transcript, Beckley, West Virginia, September 12-13, 1995.
MSHA, Permissible Exposure Limit for Diesel Particulate; Advance
Notice of Proposed Rulemaking, 30 CFR Parts 56 and 72, 57 FR 500,
January 6, 1992.
MSHA, Respirable Coal Mine Dust and Diesel Particulate Survey
Conducted at Kinney Branch No. 5 Mine, Kinney Branch Coal Company,
Pikeville, Kentucky, April 13, 1990.
MSHA, Approval Requirements for Diesel-Powered Machines and
Approval Exposure Monitoring, and Safety Requirements for the Use of
Diesel-Powered Equipment in Underground Coal Mines; Proposed Rules,
54 FR 40950, October 4, 1989.
MSHA, Air Quality, Chemical Substances and Respiratory
Protection Standards; Proposed Rule, 30 CFR Part 56 et al., 54 FR
35760, August 29, 1989.
MSHA, Report of the Mine Safety and Health Advisory Committee on
Standards and Regulations for Diesel-Powered Equipment in
Underground Coal Mines,'' July 1988.
MSHA, Notice of Establishment of Advisory Committee, 52 FR
37381, October 6, 1987.
MSHA, Policy Memorandum, 81-19MM, August 5, 1981.
Muscat, Joshua and Wynder, Ernst, ``Diesel Engine and Lung
Cancer: An Unproven Association,'' Environmental Health
Perspectives, 103:9-812-818, 1995.
National Coal Association, public comment prepared by Robert A.
Michaels, RAM TRAC Corporation, #87-0-10, July 10, 1992.
National Center for Health Statistics, Vital Statistics of the
United States 1992, Vol. II -Mortality Part A; National Center for
Health Statistics, U.S. Dept. of Health and Human Services, 1996.
National Research Council, Health Effects of Exposure to Radon:
(BEIR VI), Board on Radiation Effects Research, 1999.
National Research Council, ``Understanding Risk: Informing
Decisions in a Democratic Society,'' Stern, Paul and Harvey
Fineberg, eds., Summary, pp. 1-10, Committee on Risk
Characterization, National Press, 1996.
Nauss, K.M., et al., ``Critical Issues in Assessing the
Carcinogenicity of Diesel Exhaust: A Synthesis of Current
Knowledge,'' in Diesel Exhaust: A Critical Analysis of Emissions,
Exposures, and Health Effects, pp. 1-61, Health Effects Institute,
Cambridge, MA, April, 1995.
Navistar International Transportation Corp., ``An Analysis of
the Suitability of Steenland et al., for Conducting Quantitative
Risk Assessment of Diesel Exhaust,'' June 4, 1999.
Needham, John, ``Heavy Duty Diesel Technology for the Mid 90's
and Beyond-Worldwide Perspective, Ricardo Consulting Engineers Ltd.,
paper presented at the SAE TOPTEC Conference, April 27-28, 1993.
Newmont Gold Company, comments, EPA docket number A-95-54, IV-D-
2346, March 11, 1997.
Nielsen, P.S., et al., ``Biomonitoring of Diesel Exhaust-Exposed
Workers. DNA and Hemoglobin Adducts and Urinary 1-Hydroxypyrene as
Markers of Exposure,'' Toxicology Letters, 86:27-37, July 1996.
Nikula, K.J., et al., ``Lung Tissue Responses and Sites of
Particle Retention Differ Between Rats and Cynomolgus Monkeys
Exposed Chronically to Diesel Exhaust and Coal Dust,'' Fundamental
and Applied Toxicology, 37:37-53, 1997.
Nikula, K. J., et al., ``Comparative Pulmonary Toxicities and
Carcinogenicities of Chronically Inhaled Diesel Exhaust and Carbon
Black in F344 Rats,'' Fundamental and Applied Toxicology, 25:80-94,
1995.
NIOSH, Criteria for a Recommended Standard, Occupational
Exposure to Respirable Coal Mine Dust, U.S. Department of Health and
Human Services, September 1995.
NIOSH Analytical Method 5040, Elemental Carbon, December 14,
1994.
NIOSH, U.S. Department of Health and Human Services, public
comment in response to MSHA 1992 ANPRM, #87-OFED-2, July 10, 1992.
NIOSH, Health Hazard Evaluation Report: Yellow Freight Systems,
Inc., NIOSH Report No. HHE HETA 90-088-2110, 1990.
NIOSH, Current Intelligence Bulletin No. 50, ``Carcinogenic
Effects of Exposure to Diesel Exhaust,'' U.S. Department of Health
and Human Services, (NIOSH) Publication No. 88-116, August 1988.
Oberdorster, Gunter, et al., ``Increased Pulmonary Toxicity of
Inhaled Ultra Fine Particles: Due to Lung Overload Alone?,'' Annals
of Occupational Hygiene, Vol. 38, Supplement 1, pp. 295-302, 1994.
Oberdorster, Gunter, et al., ``Correlation between Particle
Size, In Vivo Particle Persistence, and Lung Injury,'' Environmental
Health Perspectives, 102:173-179, 1994.
Official Journal of European Countries, Information and Notices,
C-123, Volume 40, April 21, 1997.
Office of Management and Budget, Circular A-130, February 8,
1996.
Ohio General Assembly, Ohio Revised Code, Chapter 1567: Mine
Equipment, Safety Procedures. Section 1567.35, Bill Number: Amended.
Sub. S.B. 162, Effective Date: October 29, 1999.
OSHA, Air Contaminants; Final Rule, 29 CFR Part 1910, 54 FR
2332, January 19, 1989.
Oxman, Andrew D., et al., ``Occupational Dust Exposure and
Chronic Obstructive Pulmonary Disease: A Systematic Overview of the
Evidence,'' American Review of Respiratory Disease, Vol. 148, pp.
38-48, 1993.
Paas, Norbert, Public testimony presented at the ``Workshop on
Miners' Exposure to Diesel Particulate,'' Beckley, West Virginia,
September 12-13, 1995.
Parent, M.E., et al., ``Case-Control Study of Exposure to Carbon
Black in the Occupational Setting and Risk of Lung Cancer,''
American Journal of Industrial Medicine, 30(3):285-292, 1996.
Pennsylvania, The General Assembly of Pennsylvania, Senate Bill
No. 1643, Article II-A, Section 203-A, Exhaust Emission Controls,
July 22, 1996.
Perry, G.B., et al., ``Effects of Particulate Air Pollution on
Asthmatics,'' American Journal of Public Health, 73(1):50-56,
January 1983.
Peterson, Brett, and Andrew Saxon, ``Global Increases in
Allergic Respiratory Disease: The Possible Role of Diesel Exhaust
Particles,'' Annals of Allergy, Asthma, and Immunology, 77:263-270,
1996.
Pfluger, D. H. and C. E. Minder, ``A Mortality Study of Lung
Cancer Among Swiss Professional Drivers: Accounting for the Smoking
Related Fraction by a

[[Continued on page 5906]]

Notices For
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994

[[pp. 5856-5905]] Diesel Particulate Matter Exposure of Underground Metal and

Local Navigation