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53 FR 37082-37247 Friday, Sept. 23, 1988 40 CFR Parts 280 and 281, Underground Storage Tanks; Technical Requirements and State Program Approval; Final Rules--Preamble Section IV. Analysis of Today's Rule--E. Release Reporting, Investigation and Confirmation


IV. Analysis of Today's Rule

E. Release Reporting, Investigation and Confirmation

1. Overview

2. Section-by-Section Analysis


E. Release Reporting, Investigation and Confirmation

1. Overview

Because UST systems are hidden from direct observation, suspected releases must be investigated to identify, or confirm, that an UST system is the source of a release. Monitoring results and other indicators in the environment are the only suggestions of a release. In general, corrective action cannot be started until the UST system and UST site are investigated and a release is confirmed.

The proposed rule required that all suspected releases be reported to the implementing agency (see proposed § 280.50). Suspected releases included: positive monitoring results from testing, monitoring and sampling, unusual operating conditions, and the discovery of regulated substances in the environment. All suspected releases had to be immediately investigated, unless the owner and operator elected to proceed directly to corrective action.

As discussed in the preamble to the proposed rule (52 FR 12747-12751), the development and implementation of criteria and procedures to determine the appropriate circumstances to initiate, conduct and conclude the confirmation process can be technically complex. This situation is further affected by the fact that owners and operators are typically reluctant to begin what they consider to be the costly process of confirmation. Although this testing is inexpensive relative to corrective action costs, owners and operators typically want to avoid all unnecessary costs. The Agency's proposed release reporting and confirmation requirements were established in the belief that nearly all suspected releases must be investigated before conducting even more elaborate and costly abatement procedures. The first step was to quickly establish if the UST system is actually leaking. Prompt reporting of suspected releases also was proposed so that responsible authorities could take action to ensure that investigations are timely, properly designed and performed, and protective of human health and the environment.

The Agency proposed several alternative procedures for investigating suspected releases including: different combinations of tank and line tightness testing, inventory reconciliation review, testing of secondary containment, checking equipment operation, soil coring and analysis, and other methods specified by an implementing agency. Numerous comments were received in response to the proposed requirements. Most commenters took issue with the proposal's attempt to provide specific direction and guidance and suggested that even more details were needed to successfully implement this approach. For example, several commenters questioned how soil sampling results were to be interpreted and when the soil coring analysis and investigations could be accepted as definitive. In addition, commenters pointed out that the actual steps in confirmation are determined on a site-by-site basis. Other commenters were concerned with the discretion provided the implementing agencies in directing owners and operators in the investigation of off-site impacts.

As discussed elsewhere in today's preamble, EPA has received very encouraging information about the general efficacy of tank tightness testing. Also, it has become clear from comments and information received that tank tightness testing is the most prevalent technique now in use to determine if a suspect system is in fact leaking. Thus, tightness testing is a key confirmatory step in the final rule required of all owners and operators, unless they choose to immediately conduct an initial site investigation instead.

The fact that the overwhelming majority of release investigations are presently conducted using either a tightness test (as suggested by several commenters) or a small-scale site investigation has influenced the final rule as presented today. Accordingly, the five proposed investigation alternatives have been replaced with the requirement to use these two prevalent methods. Alternative methods that are no less stringent and are approved by the implementing agency are still allowed. Today's rule has been revised to more clearly establish the end point for investigation and confirmation procedures. These procedures end when a successful tightness test is obtained or when the data from environmental testing do not significantly exceed background levels. (However, these investigations may resume if additional evidence to the contrary is presented or is discovered.)

2. Section-by-Section Analysis

a. Reporting Requirements (§ 280.50). The proposal (§ 280.50) required owners and operators to report to the implementing agency within 24 hours any monitoring results from any release detection methods specified in Subpart D that indicated that a release may have occurred. Also, the observation of any unusual operating conditions at the UST system that could be indicative of a release, as well as any indication of the presence of released substances in the environment surrounding the UST, had to be reported. The proposed requirement for the implementing agency to be informed early in the confirmation process was believed necessary so that the implementing agency would be assured that proper investigation procedures were used. Commenters generally responded that it is not necessary to report all suspected releases. They identified situations in which obvious false alarms would have to be reported, and conditions that would be disruptive to the operation of the facility. They pointed out that the large number of what would prove to be unnecessary reports could overwhelm the implementing agency.

The Agency acknowledges that some of the situations brought to its attention could indeed result in a significant number of false (or unnecessary) reports. For example, the erratic behavior of dispensing equipment may warrant further investigation before reporting because this behavior can be caused by more than just a leak in the line. Accordingly, the final regulation has been revised to allow owners or operators to verify the proper operation of their equipment before reporting a suspected release. If the faulty equipment is immediately repaired or replaced and further inspection fails to confirm the initial result, the incident does not need to be reported. In the case of inventory control, the rule now allows a second month of data to be collected to verify the possibility of a release before reporting. This does not mean that all inventory discrepancies must be confirmed by a second month's data. Under some conditions, it may be necessary for owners and operators to immediately report an inventory discrepancy. What level constitutes a suspected loss depends on the size of the tank, monthly throughput, and other operating practices. The appropriate action level must be worked out in advance of using this method.

Other situations such as the physical presence of the regulated substance or unusual concentrations of vapor still require immediate reporting. (The requirement for reporting soil concentrations of 100 parts per million or more has been removed because specific national action levels cannot be established for each affected medium; a more reportable condition is whether new contamination was found based on a change from earlier conditions at this site, rather than arbitrary numerical standards and levels.) Failure to determine that an operational problem is caused by faulty equipment will also require reporting. In addition, as in the proposal, the Agency requires the owners and operators to report off-site conditions that might indicate a release has occurred and that are brought to their attention by a third party. This is intended to expedite the process of quick identification of release incidents by giving the general public additional avenues to report their observations.

b. Investigations Due to Off-Site Impacts (280.51). Under the proposed rule, the owner and operator had to investigate suspected releases that were indicated by off-site impacts and as required by the implementing agency. The unintended interpretation of this requirement was that the implementing agency could direct the owner and operator to conduct off-site investigations in response to the discovery of off-site impacts. Commenters strongly objected to this proposed requirement because they felt that it was improper to conduct investigations on property not under their control and because of the apparent wide discretion given the implementing agency in deciding what confirmation steps are needed in an off-site investigation.

The final rule includes revised language that restates the requirement so it is clear that owners and operators must investigate their own UST system and site when requested by the implementing agency and based on the discovery of off-site impacts. The potential for environmental damage is too great to allow the source of a release to go unidentified and unchecked. Limiting the investigation to the on-site UST system should minimize problems suggested by commenters associated with the investigation of releases on property owned by other parties. The Agency did not intend that owners and operators, under these regulations, must conduct investigations on property belonging to others. In the final rule, the investigation has been limited to the determination of whether the owner and operator's UST system is the source of the off-site impact. If regulated substances have been released from an owner and operator's system, as determined by an on-site investigation and confirmation, then they will be responsible for any necessary corrective action, whether on- or off-site.

c. Release Investigation Procedures (§ 280.52(a) and (b)). As discussed in the proposal preamble (52 FR 12748-12751), the Agency considered three approaches to release confirmation: detailed, step-by-step procedures; confirmation directed completely by the implementing agency; and a basic, but not detailed, set of requirements. The first approach was rejected because it is not feasible to identify and address all possible types of releases and site conditions in the regulation. The second approach was rejected because implementation of release investigation would be delayed until implementing agencies had the time and resources to determine the appropriate methods for each individual site and because owners and operators would generally delay action until their responsibilities were determined by the implementing agency. Thus, the Agency selected the third approach as providing sufficient guidance as well as flexibility.

To implement this approach, the proposed rule provided five specific procedures for release investigation. Any one procedure could be used depending on the preference of the owner and operator and the way in which a suspected release was identified. These procedures were: (1) performing a site investigation under the direction of the implementing agency; (2) checking the interstitial area of a secondary containment system; (3) in the case of a failed tightness test, checking inventory records, retesting of each portion of the system, and analyzing soil samples; (4) in the case of an inventory discrepancy, performing tightness tests and analyzing soil samples; and (5) performing any other investigation procedure that is no less stringent than those above if approved by the implementing agency. This selection of release investigation procedures was intended to address all possible situations and allow investigation to begin quickly even in the absence of guidance from the implementing agency (although such an interaction was considered most desirable).

Most commenters disagreed with the proposed approach, particularly the degree of authority given to the implementing agencies. Some of these commenters requested more specific guidance on investigation procedures, particularly what to do given certain findings and when to end an investigation. The specific investigation technique receiving the most comment was the soil coring requirement. Commenters felt it was an expensive and difficult process, the results of which are not definitive in confirming a release as there are many sources of soil hydrocarbons other than a current release. The proposed rule was also unclear about what actions should be taken based on the results of soil sampling. This requirement was proposed to be combined with the tightness test because it was believed that tightness tests might not be determinative and could not detect very small releases. This requirement was deleted in the final rule because it is now apparent (see discussion below) that tightness testing is a reasonably sensitive and reliable method. Soil sampling and analysis may still be part of the site investigations process as discussed in section (3). below.

(1) Timing of Release Investigation and Confirmation. The Agency required in the proposal that all suspected releases be investigated within seven days of initial reporting. Commenters were equally divided on whether this period was too long or too short. The Agency recognizes that there are some situations, such as the presence of product in the environment, where an immediate response to a suspected release is required. In other cases, such as when relatively small inventory discrepancies appear, greater time intervals may be allowed. The rule has been changed to recognize this: a second month of data collection is allowed for inventory control confirmation; seven days are allowed for testing of the tightness of tanks and lines; and 24 hours are allowed for checking the operation of monitoring and dispensing equipment.

(2) Tightness Test (280.52(a)). Since proposal, the results of three studies have influenced the Agency's thinking on effective release investigation procedures. The evaluation of 25 tightness test methods at the EPA Office of Research and Development's laboratory at Edison, New Jersey, (53 FR 10403) indicates that current equipment, operated with some procedural modifications, should be able to detect leaks as small as 0.10 gal/hr (see section IV.D. of this preamble for further discussion of tightness testing and these results). In California, a state with a large UST population and an active UST program (and in numerous other state and local programs), tightness testing is often the preferred approach to release investigation. The new information on the causes of release from UST systems (discussed earlier in this preamble) demonstrates that the most common sources of releases are pressurized piping and loose fittings and bungs on top of the tank, which only leak during tank overfill. The easiest way to detect releases from piping is a line tightness test, and the overfill-type of tank tightness test will identify bad fittings on top of the tank. For all of these reasons, the Agency has concluded that tightness testing is a much more effective method of release investigation than was known at proposal, is often the most logical test with which to investigate a suspected release, and is currently the most practiced confirmation tool nationwide.

Based on the above conclusion that tightness testing is the most effective first step in release confirmation, the Agency revised the final rule to ensure that the appropriateness of this method is highlighted. Consequently, the sections of the proposed rule presenting the several alternative investigation procedures have been deleted from the final rule. (In doing this, EPA agrees with several commenters that some of these procedures were incomplete and unnecessary on a site-specific basis.) In their place are two alternative investigation steps, the first of which is to conduct tightness tests to determine the integrity of the tank and piping. If the test results indicate there is a leak from a portion of the UST system that routinely contains product, the owner and operator must stop the leak and begin corrective action (releases from other portions of the UST system are addressed in reporting and cleanup of spills and overfills in § 280.53). If the tightness test indicates that the UST system is not leaking and there is not evidence of environmental contamination, the final rule does not require further actions of the owner and operator. However, if evidence of environmental contamination is still present and unexplained, the second alternative investigation step must take place. The second step requires conducting an initial site investigation (see section (3) below).

This revised approach is intended to provide clearer guidance and definitive end points as was requested by several commenters. In addition, tightness testing is a familiar technique for many owners and operators and is the most readily available and inexpensive investigation procedure. Therefore, by emphasizing its use as the primary release investigation procedure, many owners and operators will more likely begin investigation quickly on their own without waiting for the implementing agency to direct them. This capability of quick response, plus the sensitivity of tightness testing and its ability to pinpoint all sources of a leak, will minimize the potential damage to human health and the environment from a suspected release. Moreover, tightness testing is frequently the first step in corrective action to determine what must be done to stop a release. Thus, making it a part of release investigation will be cost effective for owners, operators, and implementing agencies.

(3) Site Check (§ 280.52(b)). The proposed rule (§ 280.51(a)(1)) allowed owners or operators to investigate suspected releases by conducting an initial site investigation of the UST site under the direction of the implementing agency. The final rule retains this option as the second step in the release confirmation process. The site assessment requirements in the original proposal, however, have been significantly modified to provide owners and operators greater flexibility in consideration of different site conditions. The requirements have also been modified to be more consistent with the assessment activities required under the closure and corrective action provisions of the final rule.

The initial site assessment allowed under the proposed release confirmation provisions was intended to be similar to the investigation performed under the closure and corrective action provisions. The objective of each of these assessments is to measure for the presence of released regulated substances and provide a preliminary indication of the need for and scope of further corrective action activities. They are not intended to define the full extent or location of soils contaminated by a release.

Despite this similarity in purpose, however, the proposed rule specified different sampling methods and assessment techniques. As a result, a number of commenters expressed confusion concerning the nature and scope of the assessment and requested more specific guidance on investigative procedures. Therefore, to clarify the rule's objectives and ensure that the results obtained from each type of assessment are comparable, similar site check requirements have been incorporated into the release confirmation, closure, and corrective action subparts of the final rule.

The site investigation allowed under the proposed rule had to be conducted under the direction of the implementing agency. As noted above, a number of comments criticized the degree of authority given to the implementing agency under these provisions. EPA agrees that the proposal did not give owners and operators adequate guidance for determining the objectives and goals of the site investigation. This could have resulted in wide variations in the nature and scope of the site assessments conducted under the proposal and in inconsistencies in the resulting data and their interpretation. The proposal also could have inadvertently required the implementing agencies to commit significant resources to the management of site assessments given the large number of assessments, projected to be conducted over the next 5 to 10 years. Therefore, the final rule allows the owner and operator to plan, select methods, and conduct the initial site check. These changes, however, do not diminish or restrict in any way the authority of the implementing agency to participate in the planning and performance of site investigation activities of the owner and operator. These changes will allow the implementing agency to determine the scope of their involvement in the site investigation program and, at the same time, avoid unnecessary and potentially costly delays in the implementation of each assessment by the owner and operator.

The final rule does not require the owner and operator to use a particular type of measurement method or assessment technique. A number of commenters questioned the applicability and effectiveness of the investigative procedures discussed in the proposed rule, and suggested other methods that may be equally effective in various site-specific situations. EPA agrees that a given sampling method or measurement technique may not provide representative results for all types of regulated substances and site conditions. For example, soil gas sampling may not be appropriate where the regulated substance contains compounds that are non-volatile or where the local geology and hydrology significantly restrict the movement of the volatilized organic species.

To address this problem, the final rule requires the owner and operator to measure for the presence of regulated substances in the area where contamination is most likely to be present. Any factors that may affect the identification of the source or presence of contamination must be considered in order to ensure that the assessment will provide accurate and reliable results. The rule specifies the factors deemed to be the most important in selecting the measurement method and in conducting the initial site check.

Measurements must be taken in the area surrounding the UST system where contamination is most likely to be present. Samples may be collected from any depth as long as they are taken where contamination is most likely to have migrated or accumulated given the specific characteristics of the site and the regulated substance. Most regulated substances will tend to migrate down and, as a result, the Agency believes that samples taken at depths below the UST system's suspect components will generally satisfy the requirements of this subsection. The contaminants in some regulated substances, however, may float on the water table or dissolve in the ground water. Consequently, the nature of the regulated substance and the depth to ground water around the UST system are important factors to be considered when developing an assessment plan.

The owner and operator may also find it necessary to conduct the initial check in an area that extends outside of the excavation zone of the UST system. Although the Agency believes that sampling in the excavation zone will generally provide the most accurate information about the presence and source of contamination at an UST site, it may not be possible to identify the precise location of the excavation zone or gain reasonable access to the areas adjacent to the tank and piping due to interfering structures. In addition, samples taken from the excavation zone will not give any information concerning the extent of contamination. Where contamination poses an imminent threat to human health and the environment on adjacent property, it may be more appropriate to take samples at or near the site's property line that is adjacent to the off-site point of impact. For example, seepage of liquid or vapors into occupied residences or into drinking water supplies may necessitate sampling at the adjoining property line so that corrective action activities can be expedited. In such cases, the mitigation of contamination in the soil or ground water around the building or well may be more important than first identifying the cause of the contamination, particularly where there are several possible sources of suspected releases.

The specific factors identified in the final rule were selected to ensure that representative assessment information is obtained during release confirmation. Consideration of these factors by the owner or operator is deemed by EPA to be the minimum requirements for adequately evaluating the area surrounding the tank. They are not intended to be exhaustive nor should they be given equal weight at all sites. The importance of each of the factors must be evaluated carefully in view of the regulated substances suspected of being present and the specific conditions at the site.

d. Reporting and Cleanup of Spills and Overfills (§ 280.53). In the proposal, the Agency specified that spills and overfills which resulted in the release of a regulated substance meeting or exceeding the reportable quantity (RQ) under CERCLA (40 CFR 302), or spills and overfills of petroleum exceeding 25 gallons or causing a sheen on surface water, must be reported to the implementing agency with 24 hours. The proposed approach has been maintained in the final rule.

In the preamble to the proposed regulation, the Agency requested comments on the appropriateness of the reporting cutoff of 25 gallons for aboveground releases of petroleum to land and surface water. Commenters were divided on this issue. Many supported the 25-gallon cutoff while some requested that it be raised to much higher levels and a few requested that it be lowered. The Agency has retained the proposed reporting levels while allowing individual state and local implementing agencies the ability to select other amounts under certain conditions. In all cases, the spill or overfill must be immediately contained and cleaned up, and, if it is not, then it must be reported to the implementing agency. The point at which a report must be submitted to the implementing agency is an administrative convenience, and the Agency intends to leave some discretion to the states on this area.

The Agency believes that spills often occur at many of the facilities in this regulated community. In fact, knowledgeable members of the regulated community have reported to EPA that spills and overfills are the second most common source of release to the environment. This conclusion is based in part on observations made during tank removal of obviously contaminated soil around areas of the tank where spills might be expected to occur. This soil contamination can be caused by emptying fill hoses onto the ground after delivery, either by accident when the hose is disconnected from the tank or on purpose when the tank is inadvertently overfilled and the hose cannot be drained into the tank. Although any one incident may or may not result in a significant threat at a particular site, the Agency has concluded that the repeated occurrence of these releases over time does represent a serious threat to human health and the environment.

The concern about spills reporting is that spills appear to occur very frequently, although generally in small quantities. The requirement to report all spills, regardless of their size, could cause the implementing agency to be overwhelmed with reports of numerous small spills that do not represent a significant threat to human health and the environment. The Agency believes very little threat is posed by smaller spills if they are contained and immediately cleaned up, including contaminated surface soils. The installation of catchment basins required in Subpart B in the final rule should reduce the number of releases to the environment, the cost of cleanup for owners and operators and the number of incidents where reporting is necessary.

The Agency has retained the proposed RQ approach to indicate to the owner and operator when reporting is necessary. For petroleum, this approach requires reporting of aboveground releases to land in excess of 25 gallons, and of aboveground releases to water if the result is an oil sheen on the water, in accordance with the requirements of 40 CFR Part 110. The rationale for this was provided in the preamble to the proposal. The Agency also recognizes that, in some cases, it may not be possible to immediately clean up a spill of less than 25 gallons. When this occurs, the owner and operator is required to report the spill to the implementing agency.

A spill or overfill resulting in the release of a hazardous substance to the environment must be reported if the volume equals or exceeds its RQ as defined under CERCLA (40 CFR 302). The RQ for a particular hazardous substance may result in a volume that is less than 25 gallons. The Agency feels it is necessary to place tighter controls on hazardous substances because of their generally greater threat to human health and the environment. An additional discussion of this issue is provided in section VI.A. of this preamble. The release of a hazardous substance equal to or in excess of its RQ must also be reported to the National Response Center immediately (rather than within 24 hours) under sections 102 and 103 of CERCLA and to appropriate state and local emergency response authorities under Title III of SARA. The requirements of today's rule do not change the responsibilities of owners and operators to meet the requirements of these other EPA rules. Thus, in the case of a spill or overfill of a regulated hazardous substance from an UST, the owner and operator is subject to two reporting requirements. The impact of additional reporting, however, is minimal because the goal of The National Response Center is essentially to inform local implementing agencies. This will already have been done when the owner or operator fulfills the requirements in today's rules.

Although reporting triggers have been established for aboveground releases, this does not relieve the owner and operator of the responsibility to undertake all other appropriate elements of the corrective action process under Subpart F for any aboveground release, regardless if it is more or less than the reportable quantity.

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