Frequent Questions: Final Standards for Hazardous Air Pollutants for Hazardous Waste Combustors
1. What was the scope of the October 2005 final rule?
The hazardous waste combustor final rule was promulgated on October 12, 2005 and established national emission standards for hazardous air pollutants for sources that burn hazardous waste: commercial and onsite incinerators, cement kilns, lightweight aggregate kilns, boilers, and hydrochloric acid production furnaces. These standards were promulgated pursuant to Section 112 (d) of the Clean Air Act, which requires EPA to issue technology-based standards reflecting the performance of the Maximum Achievable Control Technology (MACT).
The standards limit emissions of:
- dioxins and furans,
- semivolatile metals (cadmium and lead),
- low volatile metals (arsenic, beryllium, and chromium),
- particulate matter, as a surrogate for non-mercury metal, hazardous air pollutants, including
- hydrogen chloride and chlorine gas, and
- organic hazardous air pollutants.
Where control of the feed of hazardous air pollutants (HAP) was feasible and technically assessable, we used a methodology that ranked sources by their ability to control HAP feed and their ability to control emissions of HAP that are fed to the combustion device (measured as system removal efficiency). This methodology thus assessed the efficiency of controlling both the HAP inputs to a hazardous waste combustion unit, and the efficiency of control of the unit's outputs.
This methodology selected the best performing sources (and for new sources, the single best performing source) and assessed their level of performance. This methodology accounted for variability in emissions levels occurring from test to test, even by the best performing sources.
In assessing best performing sources' level of performance, we quantified certain types of variability, notably analytic measurement variability that is an inherent component of performance tests, and run-to-run variability (variability in source's performance in the multiple runs that are averaged to yield the results of a combustion performance test). We also expressed sources' performance in terms of a parameter (a "normalizing parameter") relating to a source's function (either volumetric gas flow rate or, for energy recovery units, heating value of hazardous waste fuel) so that performance of sources of different size could be directly and meaningfully compared.
5. Why did EPA give sources the option to comply with
health-based emission standards for total chlorine in lieu of technology-based
standards in the October 2005 final rule?
Under authority of CAA Section 112(d) (4), we promulgated standard procedures to allow owners and operators to establish a health-based emission limit for total chlorine in lieu of compliance with the section 112(d) (2) MACT emission standard. The health-based approach is available to all hazardous waste combustors except hydrochloric acid production furnaces. Because we finalized the MACT standard for total chlorine as a surrogate to control metal HAP, we did not allow any alternative to the chlorine standard for this source category.
The alternative health-based emission limit for total chlorine is based on national exposure standards established by EPA that ensure protection of public health with an ample margin of safety. The standard consists of assuring that individual source emissions will not exceed a nationally-applicable, uniformly protective national exposure standard. Each source's standard is based on site-specific input from each source choosing to use this approach.
Monetized human health and visibility benefits were estimated to range from $5.61 million per year to $6.31 million per year, depending on the discount factor applied for mortality benefits. It is important to emphasize that monetized benefits represented only a portion of the total benefits potentially associated with this rule because we were not able to monetize a large portion of benefits. Specifically, ecological benefits, and human health benefits associated with reductions in mercury, and lead, were not quantified or monetized. In some locations these benefits may be significant. Visibility benefits were also expected. We did not expect the final standards to result in significant waste minimization in the short run. However, we found that more substantial waste minimization may occur in the long run as facilities design and/or adopt new production technologies.
Total annual social costs associated with the final standards were estimated at $22.6 million per year. This estimate included all relevant government costs, and anticipated market adjustments (e.g., price changes, waste diversions, system exits). Under this scenario, commercial incinerators, cement kilns, and lightweight aggregate kilns were projected to experience net gains as a result of the final standards. This was based on increased waste receipts, marginal price increases, and comparatively lower upgrade costs. Our conservative cost scenario, of $40.7 million per year, assumed no market adjustments. Under this scenario, liquid and solid fuel boilers, and hydrochloric acid production furnaces accounted for about 85 percent of the total costs.
EPA estimated that hazardous waste combustors annually emit approximately 12,650 tons of hazardous air pollutants (metals, total chlorine, organics and dioxin/furans) and particulate matter. Depending on the number of facilities demonstrating compliance with health-based compliance alternatives standards for total chlorine, the total reduction of HAP and particulate matter for existing sources was estimated to be between approximately 2,260 and 3,380 tons per year.
EPA found that this rule will also protect human health and the environment by reducing particulate matter in conjunction with the air toxic reductions. EPA estimated that particulate matter reductions could be as high as 2,140 tons per year.
9. Did EPA repromulgate all the compliance provisions
for incinerators, cement kilns, and lightweight aggregate kilns in the October 2005 final rule?
EPA did not repromulgate the 1999 compliance provisions (provisions that specify the means by which sources comply with the emission standards, which include testing, operating limits, notification, reporting, and recordkeeping requirements) for incinerators, cement kilns, and lightweight aggregate kilns. The final rule adopted these same compliance provisions for Phase II sources--boilers and hydrochloric acid production furnaces.
All Phase II sources (boilers and hydrochloric acid production furnaces) are required to submit a notification of intent to comply (NIC). EPA also required Phase I sources (incinerators, cement kilns, and lightweight aggregate kilns) that need to make upgrades to comply with the final rule standards or that have not previously submitted a NIC, to submit a NIC.
The NIC serves as a compliance planning and communication tool. We anticipate that Phase I sources may need to conduct additional upgrades, or in some cases upgrade for the first time, to comply with the replacement standards. We found that re-instituting the NIC for these sources would provide the same planning and communication benefits during the compliance period for the replacement standards that it did for the original Phase I standards. In addition, we believe that the NIC provides the same benefits with respect to communication and compliance strategy planning for the Phase II sources that it has for Phase I sources.
The requirements were codified in 40 CFR Part 63, Subpart EEE.
12. Upon demonstrating compliance with the MACT standards,
will sources still be required to have a RCRA permit?
Yes. Phase I (cement kilns, incinerators and lightweight aggregate kilns) and Phase II (boilers and hydrochloric acid production furnaces) sources still need a RCRA permit to operate even after they submit a Notification of Compliance documenting compliance. However, the RCRA permit only needs to address basic hazardous waste management including: general facility standards; corrective action; other hazardous waste management units (such as storage units); other combustor-specific concerns such as materials handling; and, any risk-based combustor emission and operating requirements that are more stringent than the relevant MACT standard. (The inapplicable RCRA combustion performance standards of 40 CFR Parts 264, 265, 266, and 270 can be removed from the RCRA permit via a streamlined permit modification procedure.) The Clean Air Act title V permit will focus on the operation of the combustion unit including the MACT air emission standards and related operating parameters.
EPA issued a rule on December 19, 2005, amending three bag leak detection system requirements (BLDS) for incinerators, cement kilns, and lightweight aggregate kilns. A bag leak detector is an instrument capable of monitoring changes in particulate matter emissions for the purpose of detecting fabric filter bag leaks or similar failures. In the October 12, 2005 final rule, we inadvertently included three new or revised BLDS requirements among implementation requirements taking effect on December 12, 2005 (i.e., the effective date of the October 2005 final rule), rather than, as intended, after three years when these sources begin complying with the revised emission standards. We intended to establish the compliance date for these provisions three years after promulgation because the provisions establish more stringent requirements for these sources, which cannot readily be complied with on short notice. The BLDS amendments issued on December 19, 2005, correct the date to October 14, 2008.
14. How is EPA addressing the issues raised in the "petitions for reconsideration" that were submitted to the Administrator following promulgation of the October 12, 2005 final rule?
Following promulgation of the MACT final rule, issued on October 12, 2005, the EPA Administrator received four petitions for reconsideration pursuant to section 307(d)(7)(B) of the Clean Air Act. Under this section of the Clean Air Act, the Administrator shall initiate reconsideration proceedings if the petitioner can show that it was impracticable to raise an objection to a rule within the public comment period or that the grounds for the objection arose after the public comment period. For each issue raised in the petitions of reconsideration, EPA must either grant or deny reconsideration, based on a determination of whether EPA provided adequate notice during the rulemaking.
EPA granted reconsideration of eight issues raised by the petitioners and provided the public with an opportunity to comment on them by issuing two proposed rules. In the first notice published on March 23, 2006, EPA granted reconsideration of one issue - the particulate matter standard for new cement kilns - and requested comment on a revised standard.
In the second reconsideration notice published on September 6, 2006, EPA provided the public with an opportunity to comment on seven additional issues:
EPA also decided not to reconsider several issues raised in the petitions for reconsideration. Included in the docket to this rulemaking are letters to the petitioners explaining our rationale to deny reconsideration.
- subcategorization of liquid fuel boilers;
- correcting total chlorine emissions data below 20 ppmv;
- use of Performance Specification 11 as a reference to develop alarm set-point extrapolation procedures for particulate matter detection systems;
- approach to identify the best performing single source when two or more sources are tied for the lowest aggregate system removal efficiency/feedrate score;
- beyond-the-floor analyses to consider multiple HAP that are controlled by a single control mechanism;
- use of post-proposal data to identify the dioxin/furan standard for incinerators with dry air pollution control devices or waste heat boilers and
- three provisions of the health-based compliance alternative for total chlorine.