Fourth, several commenters offered their views about the appropriate timing of product removal.  Most commenters agreed with EPA's proposal that free product removal operations should begin as quickly as possible, but cautioned that hasty and improperly conducted removal could spread contamination vertically at the site.  In the final rule, EPA continues to require that removal begin as quickly as practicable (§ 280.62(a)(6)).  Revised § 280.64(a) emphasizes, however, that free product removal must be conducted in a manner that minimizes the spread of contamination and that is appropriate to the hydrogeologic conditions at the site.  EPA is aware, for example, of site conditions where trenching or vapor extraction to recover free product would be preferable to drawing down the water table--and the free product plume--in order to collect and remove free product.  EPA is preparing technical resource documents to assist implementing agencies in advising owners and operators about potential complications when removing free product.  Similarly, in response to commenters concerns, EPA has extended the time period for owners and operators to report to implementing agencies concerning their free product removal from 30 to 45 days.  This change will allow owners and operators more time to properly plan for free product removal, especially for removal operations involving dense product or at hydrogeologically complex sites.

	In addition, some commenters requested EPA clarify permitting requirements for discharges from the product recovery system.  Others suggested that EPA exempt UST cleanups from NPDES requirements or establish numerical limits for emergency permits.  In response, EPA has revised § 280.64(a) to clarify that all discharges are to be properly treated, in compliance with applicable federal, state and local regulations.  In addition, EPA is investigating methods to expedite, where applicable, the NPDES permitting process for discharges necessitated by UST corrective action.

f.  Investigations for Soil and Ground-Water Cleanup (§ 280.65)

	Proposed § 280.63 has been renumbered § 280.65 in the final rule.  As proposed, this section required the owner and operator to investigate the extent of soil and ground-water contamination at an UST release site when the initial site investigation showed that contaminated soil remained at the site, or when the required soil removal showed that the released product or product from contaminated soil may have reached ground water.  In addition, the implementing agency could direct the owner and operator to conduct such an investigation.

	Several commenters requested that EPA clarify the minimum sampling requirements for these investigations.  Other commenters suggested that these more extensive investigations be better coordinated with the soil and ground-water sampling required earlier in the corrective action process.  One commenter noted that the phrase "product from contaminated soil" would be difficult to define and might be interpreted to require extensive investigation at virtually all sites.  In addition, EPA recognizes that some amount of contaminated soil will be present at most UST release sites, but that the threat posed by this contamination will depend on several factors.

	In response to these comments, EPA has revised this section to clarify the situations that trigger more extensive site investigations.  EPA notes that the objective of these investigations is to support decisions concerning whether soil and ground-water cleanup or other corrective action measures are necessary at the site.  Consequently, EPA has revised the rule to better relate these requirements to site-specific threats to ground-water contamination.

	Final § 280.65 discribes three specific site circumstances requiring full for characterization of soil and ground-water contamination: (1) when release confirmation or previous corrective action measures indicate that ground-water wells may have been affected by the release, (2) when free product is found on the water table or within the aquifer, and (3) when any other site investigations show that contaminated soil may be in contact with ground water.

	EPA recognizes that characterization of soil and ground-water contamination may also be necessary at sites where there are no "automatic triggers."  Thus, the final rule retains the authority of the implementing agency to request an investigation.  Final § 280.65(a)(4) clarifies that the implementing agency should consider the potential effects of contamination at the site in relation to nearby surface and ground-water resources when deciding whether further investigations are warranted.  In particular, EPA expects that information required under § 280.63 will provide implementing agencies with important information for determining if more extensive investigations are required.

	In revising the rule, EPA sought to better tailor the investigation requirements to site conditions that pose a potential threat to ground-water resources.  EPA believes the final rule clarifies those situations that trigger more extensive site investigations and better coordinates the objectives of the revised corrective action requirements within a site-specific framework.

g.  Corrective Action Plan (§ 280.66)

	In the final rule, proposed § 280.64 has been renumbered as § 280.66 and retitled as "Corrective Action Plan."  This revised section responds to commenters' requests for clarification of the owners' and operators' responsibilities for submitting corrective action plans (CAPs) and of the implementing agencies responsibility to request, review, and approve a CAP.  Subtitle I of RCRA directs the Agency to promulgate corrective action regulations applicable to owners and operators of UST systems.  The corrective action plan approval process, however, integrates the responsibility of owners and operators to ameliorate the adverse effects of UST releases with the responsibility of implementing agencies to determine how they will carry out their established public health policies.  EPA's role is to:  (1) establish the responsibility of owners and operators to achieve adequate protection of human health, and (2) establish a baseline framework for evaluating and approving corrective action plans.

	Several commenters requested clarification of the owners' and operators' responsibilities for corrective action beyond immediate abatement steps and removal of free product.  In response, § 280.66(a) of the final rule has been revised to clarify that owners and operators are responsible for submitting, when requested by the implementing agency, a corrective action plan that provides for adequate protection of human health and the environment.  Section 280.66(b) of the final rule sets forth the factors that implementing agencies must consider when approving a corrective action plan.  Consequently, this section also serves to inform owners and operators of the minimum elements required in the plans they submit.

	Some commenters suggested the Agency establish explicit criteria that implementing agencies could use to determine whether a CAP is needed and to evaluate CAPs after they are submitted.  As described in the preceding sections, EPA has revised several parts of the proposed rule to clarify the objectives of each step of the corrective action process.  Owners and operators are responsible for carrying out and reporting these actions, thus providing the implementing agency with a good basis for determining the necessity for additional cleanup.

	EPA believes it would be difficult and unproductive to incorporate more explicit evaluation criteria in today's rule.  As described earlier in this preamble, EPA received wide support for the proposed site-specific corrective action goals and has retained this approach in the final rule.  Implementing agencies, however, may choose to develop their own site-specific corrective action goals, or they may base cleanup goals on statewide numerical standards or aquifer characteristics.  Rather than develop criteria that may conflict with a state or local agency's preferred method, EPA has chosen to identify in the rule those factors that are generally necessary for carrying out corrective actions regardless of the chosen method for setting precise cleanup goals.  For example, these factors include the persistence of the released substance and the hydrogeologic conditions at the site.  EPA sees its role primarily as providing technical support for interpreting these factors in the context of site-specific application of corrective action technologies.  In particular, EPA is developing technical information and supporting materials to assist implementing agencies in relating site assessment results to the feasibility of alternative technologies, and for evaluating how well these technologies are achieving cleanup at a site.  In addition, EPA is beginning to develop methods to expedite exposure assessments.  Other programs within EPA, such as the Office of Ground-water Protection, may also be called upon to provide support for evaluating ground-water resources.

	The overall objective of longer term UST corrective actions is to adequately protect human health, safety, and the environment from contaminants remaining in soils or ground water after initial abatement measures and free product removal.  The Agency prefers that this objective be achieved, where practicable, through reducing contaminant concentrations in soil or ground water to levels protective of health and the environment.  In some situations, however, the Agency would require--under the standard in § 280.66(a)-- that human health be protected from exposure to contaminants through other appropriate measures, such as providing an alternative water supply.

	EPA cannot project the outcome of its site-specific approach to all UST releases because the consideration accorded to some factors, such as aquifer resource value and its current and potential use, is largely left to state and local policy.  If an UST release affects a public or private drinking water source, however, the owner and operator must expect that the state's health-based drinking water standards would apply to the cleanup.  If the owner and operator cannot meet these standards through cleanup technologies, then they should expect that they will be required to provide an alternate source of drinking water or to provide treatment of the water to the people affected.  Similarly, the owner and operator should expect that UST releases that threaten current or potential water supplies will come under close scrutiny by the implementing agency.  In these cases, the corrective action requirements will likely be influenced by the mobility of the contaminants at the site and the estimated time and spatial extent over which the remaining contamination may pose a threat.  At a minimum, approved CAPs would likely include requirements for long-term monitoring, continued control of ground-water flow at the site, and notice of continuing hazard in the property deed.

	The final rule retains the implementing agency's authority to require submission of a CAP based on information received from early corrective action measures.  (EPA expects, for example, that implementing agencies might choose this option for UST releases that are of great magnitude or in close proximity to drinking water resources.)  Final § 280.66(a), however, has been revised to make clear that the implementing agency must first review the submitted material before requesting the submission of a CAP or additional information.  This section also has been revised to enable owners and operators to submit a CAP for soil and ground-water cleanup based on their own initiative and assessment of the severity of the release.  They need not wait for the implementing agency to request a CAP.

	Several commenters expressed concern that lengthy reviews by the implementing agency might slow the pace of UST cleanups, creating delays that could make implementing the final CAP more difficult, because of the spread of contamination while delays persist.  Some commenters also suggested that owners and operators should be allowed--after a specified length of time--to interpret inaction on the part of the implementing agency as approval of the CAP.

	Given the number of releases that are expected to be detected in the near future, EPA acknowledges that there is potential for delayed cleanups under the proposed approach if implementing agencies are unable to review all the CAPs in a timely manner.  The Agency concluded, however, that the alternatives suggested by commenters were inappropriate.  To respond to this issue, however, § 280.66(d) has been added to allow owners and operators to begin cleanup of soil and dissolved contaminants in ground water without CAP approval provided they:  (1) first notify the implementing agency of their intention to begin cleanup, (2) comply with modifications imposed by the implementing agency, including halting cleanup activities, and (3) incorporate these initial measures in the CAP to be reviewed and approved by the implementing agency.

	EPA has added this provision with the goal of encouraging effective and expedited cleanup of soil and ground water.  EPA emphasizes, however, that the implementing agencies remain the final arbiter for approving CAPs.  Implementing agencies, therefore, can require the owner and operator to revise their CAPs and to modify the cleanup techniques in use at a site, including mitigating adverse consequences of cleanup activities.  Since the implementing agency retains this authority, EPA expects that owners and operators who choose to initiate cleanup prior to approval of this CAP will select cleanup technologies that are widely used and recognized to be effective.  EPA believes some cleanup techniques, such as extraction and treatment of petroleum vapors from soils, can be initiated with little risk of worsening contamination at the site.  EPA also notes that states need not adopt the policy of owner- and operator-initiated cleanup for state program approval.  Moreover, if states choose this option they can tailor its use to best meet their needs.  For example, the implementing agency can identify specific cleanup technologies that are widely applicable without prior review or approval and those that always require explicit plan approval.  Similarly, implementing agencies can decide to limit this option for use only at releases from certain USTs, such as petroleum USTs.

h.  Reporting (Proposed § 280.65)

	The reporting requirements in this section of the proposed rule have been consolidated with the requirements in § 280.51 of the final rule because they are part of the release confirmation process.

i.	Public Participation (§ 280.67)

	The proposed public participation rule required implementing agencies to provide opportunity for public review and comment on all CAPs and to consider these comments before approving CAPs.

	Although commenters agreed that public participation is desirable, many commenters expressed concern that protracted public participation during the development of all CAPs could unnecessarily delay some UST cleanups.  For example, cleanup efforts could be delayed while the development of a CAP was submitted to lengthy public review and deliberation.  Also, mandating public participation for all CAPs could divert implementing agency resources from other cleanup activities such as oversight of ongoing cleanup operations.

	EPA agrees with commenters who urged that implementing agencies strike a balance between the involvement of the public in corrective action decisions and the sometimes competing need to protect human health and the environment through quick and effective responses to an UST release.  To acknowledge these sometimes conflicting objectives, the final rule for public participation establishes a flexible approach that ensures public access to available information on UST cleanups, although the public need not be involved, as a matter of routine, in all CAPs.

	Implementing agencies continue, however, to have the responsibility and authority to notify the public about CAPs, to provide public access to the site and cleanup files, and to involve the public in meetings if sufficient interest is demonstrated.  The final rule's public participation requirements for UST corrective action stress the need for adequate public notice, particularly to those parties who could be directly affected by the release and the planned corrective action.  EPA expects that the public will be provided adequate opportunity to participate in and aid the UST cleanup process.

	EPA does not agree with those commenters who opposed including any public participation requirements in the UST corrective action rule.  In particular, EPA does not agree with the concerns raised that RCRA does not explicitly require public participation under Subtitle I.  EPA believes that section 7004 of RCRA specifically mandates that all of the Agency's RCRA programs provide for the opportunity for public participation, including the RCRA Subtitle I program.  This statutory mandate, combined with long-standing EPA policies to involve the public in the cleanup of contaminated sites, has prompted EPA's decision to keep the public participation requirements in Subpart F.  In meeting this need, however, EPA has intended to require public notice and participation in UST corrective actions in a form that does not unnecessarily disrupt what state UST programs already require and provide.

	The final rule requires public notification and public availability of information on CAPs.  The implementing agency must notify the public about each confirmed release requiring a CAP.  This notification requirement remains as proposed, although the rule no longer mandates implementing agencies to formally consider and respond to public comment before approving a CAP.  The implementing agency must also provide public notice if implementation of the CAP does not achieve the established cleanup levels and the implementing agency is considering terminating the CAP.  In most states, those affected by the release are often kept well informed through personal contacts with the state response staff.  Today's requirements are not intended to change this practice of personal contact as one of the first points of public notice in the existing state UST programs.  This method of notice has been added to the rule to make this clear.  The list of public notice vehicles contained in the rule, however, is not intended to be exhaustive.

	In addition to this notification requirement, the final rule requires the implementing agency to provide public access to site release information and decisions concerning the CAP.  By providing public notification and access to information, implementing agncies ensure the opportunity for public participation in specific CAPs of interest to the affected sectors of the public.  Because the Agency considers public notification and public access to information to be the key components of public participation for all CAPs, the final rule emphasizes the importance of these two requirements.

	The implementing agency may hold a public meeting to consider public comments on a CAP if sufficient public interest is shown concerning a proposed CAP.  EPA uses the phrase "public meeting" in the rule to emphasize that a formal public hearing is not required.  EPA intends that a public forum be provided, in keeping with the state's administrative procedures, to inform the public and allow public comment on a CAP.  The implementing agency will decide when public meetings are warranted on a case-by-case basis.  EPA expects that large releases involving extensive corrective action will include correspondingly more extensive public participation because public understanding and acceptance is critical to the success of these CAPs.

	In summary, the final rule emphasizes the implementing agency's responsibility to involve the public in a manner that best serves the environmental goals of the CAP.

G.	Out-Of-Service UST Systems and Closures

1.  Introduction

	As discussed in the preamble to the proposed rule, the principal objective of the UST system closure requirements is to identify and contain existing contamination and to prevent future releases from UST systems no longer in service (52 FR 12757).  Available information suggested that UST systems improperly closed in the past have had undetected releases that later required corrective action.  More of these systems may be found to have leaked and, in the future, require additional corrective action.  Because a large number of existing UST systems are expected to close in the next 5 to 10 years, EPA believes that it is particularly important to require proper management procedures for out-of-service UST systems so that contamination due to improperly closed UST systems can be prevented from posing a threat of additional releases in the future and needed corrective action can be identified and taken.  The comments on the proposal generally acknowledged that proper closure is an important aspect of sound UST management.

	The closure procedures are covered in §§ 280.70 through 280.74 of the final rule.  Section 280.70 describes the requirements that must be complied with at all UST systems temporarily closed for less than 12 months.  It also requires tanks that do not meet requirements for new or upgraded USTs, and that are taken out of service for 12 months or longer, to permanently close.  Those USTs that do meet requirements for new or upgraded USTs can remain indefinitly out of service.  Section 280.71 provides requirements for permanently closing or changing the service of an UST system, including identification of alternative methods for permanent closure and procedures for continuing the service life of an UST system when it is to be used for the storage of non-regulated substances.  Section 280.72 describes the requirements for assessing the UST system excavation zone at closure.  Section 280.73 requires owners and operators to apply the permanent closure and site assessment requirements of the final rules to UST systems taken out of service before the effective date of the regulations, if so directed by the implementing agency.  Section 280.74 lists the recordkeeping requirements.  These proposed requirements, highlights of public comments on them, and the Agency's approach to the final UST system closure standards are discussed in more detail below.

2.  Temporary Closure (§ 280.70)

	To prevent owners and operators from improperly closing UST systems in the future, EPA proposed requirements in § 280.80(a)-(b) for tanks temporarily taken out of service for up to 24 months.  These provisions only covered UST systems when a regulated substance was left in the tank and did not distinguish between unprotected tanks and protected tanks that met the requirements for new or upgraded UST systems.

	The applicability of these requirements depends upon what constitutes temporary closure.  Although a number of suggestions were received, generally commenters recommended defining temporarily closed based on both the use of the tank and how frequently regulated substances are typically moved through it.  The failure to fill and/or take regulated substances from a tank on a regular basis, however, was not always considered to be a reasonable criterion for determining the tank was temporarily closed.  Commenters cited several examples of infrequently used tanks where temporary closure was not appropriate, including emergency generator tanks and backup system tanks from which fuels were not typically dispensed for long periods of time.

	The Agency believes that owners and operators will generally pay more attention to tanks that are used frequently than to those that are used only occasionally or are temporarily closed.  Thus, the operation and maintenance procedures used to ensure the integrity of a tank and the effectiveness of release detection efforts instituted to identify leaks in and around a tank will be somewhat related to whether the tank is being actively used or not.  Other possible factors in determining whether a tank is temporarily closed include adherence to the normal operation and maintenance procedures at the facility, the types and amounts of regulated substances stored at the facility, the likelihood that an undetected leak has occurred or may occur in the future, and the potential that the tank has become a receptacle for illegal dumping.  The Agency does not intend that the emergency generator and backup fuel system tanks cited by commenters should be subject to automatic closure requirements merely because regulated substances are not moved through the tanks on a regular or frequent basis.  If, however, the infrequent use of such a tank cannot be justified as part of its purpose and/or if the operation, maintenance, or release detection procedures associated with the tank are inadequate or inconsistent with the monitoring procedures required for operating tanks, the tank will be considered temporarily closed and, after 12 months is up, subject to permanent closure requirements in accordance with § 280.70(c) of the final rule.

	Several commenters pointed out that proposed § 280.80(a)-(b), which covered temporary removal from use and temporary closure, only applied at tanks where the regulated substances were left in the tank.  As a result, if the regulated substances were removed from the tank, the proposed rule appeared to exclude UST systems from the further application of the temporary closure provisions.  EPA intended, however, that the closure requirements should be applicable to all UST systems that are taken out of service regardless of the quantity of regulated substance remaining in the tank.  The Agency also believes that continuation of release detection is not necessary when the regulated substances and residual material have been adequately removed from the UST system.  Therefore, the revisions to § 280.70(a) of the final rule subject tanks from which the regulated substances have been removed to the temporary closure provisions, but allows the owner or operator to discontinue release detection as long as the UST system is completely empty.

	The final rule also does not contain a requirement to test the integrity of a temporarily closed tank before refilling, although several commenters suggested that such a test should be conducted before materials are reintroduced into an empty tank.  EPA does not agree that such a requirement would provide significant benefits. There is no evidence that empty tanks are more vulnerable to structural failure than filled tanks.  In addition, the Agency believes that the release detection standards set forth in the final rule are sufficient to rapidly detect any leaks or structural failures that may occur once the system is brought back into service.

	Several commenters requested guidelines for determining when an adequate amount of the regulated substance has been removed from a tank to preclude the tank from the temporary closure requirements.  In response to these comments, the final rule makes it clear all tanks that contained a regulated substance are subject to the temporary closure requirements regardless of the amount of material remaining in the tank when it is taken out of service.  If the tank is empty, however, the owner and operator are not required to maintain release detection around the tank.  The term "empty" is defined by incorporating the definition of "empty container" set forth in EPA regulations under Subtitle C of RCRA.  This definition requires all materials to be removed that can be removed using commonly employed practices.  No more than 2.5 centimeters (one inch) of residue or 0.3 percent by weight of the total capacity of the tank can remain in the system.  EPA believes that this definition is adequate to ensure that the regulated substances remaining in the tank will not pose an unreasonable risk to human health and the environment if a release occurs during the temporary closure period.

	To prevent owners and operators from indefinitely postponing permanent closure, EPA proposed in § 280.80(c) that all tanks be closed that had been out of service for more than 24 months.  This period was considered a reasonable time for tank owners and operators to decide whether to permanently close or continue the use of a tank a tank.  The period recommended to be allowed for temporary closure by commenters varied greatly.  Commenters cited numerous cases where mandatory permanent closure after 24 months of temporary closure was neither appropriate nor justified.  Most state regulatory authorities commenting on this proposal recommended a shorter temporary closure period.

	One of the principal reasons cited by the commenters recommending extending the temporary closure period was that tanks in compliance with the appropriate corrosion protection and leak detection procedures do not pose a significant threat of future releases.  The commenters also argued that the permanent closure of such tanks would create an economic hardship without providing any significant environmental benefit.  EPA agrees with these commenters that UST systems that are adequately protected from corrosion and equipped with release detection systems pose a significantly lower threat to human health and the environment than unprotected tanks.  This conclusion is also consistent with the comments submitted by state regulatory authorities that recommended a reduction of the closure period.  Their recommendations are believed to stem primarily from the states' experience with unprotected, bare steel tanks and, consequently, strongly suggest that significant damage to the public health and the environment could occur if unprotected tanks are allowed to temporarily close and are left unattended for long periods of time.  Therefore, § 280.70(c) in the final rule reduces the allowed period for temporary closure of unprotected tanks from 24 months to 12 months.  Any temporarily closed UST systems that do not comply with the performance standards for new tanks under § 280.20 or the upgrade requirements for existing tanks under § 280.21 must permanently close after the 12 month temporary closure period ends.  However, UST systems that comply with the performance standards for new or upgraded UST systems set forth in the final rule may remain out of service indefinitely so long as they remain in compliance with the operation, maintenance, and release detection requirements of the final rule.  Since spilling and overfilling associated with product transfer should not be a problem around tanks that have been temporarily closed, UST systems are not required to satisfy the spill and overfill requirements for new and upgraded systems in order to be excluded from the 12 month permanent/closure provisions in the final rule.

	Many commenters also believed that owners and operators should have a mechanism for seeking and obtaining an extension of the temporary closure period (to avoid the permanent closure requirements) on a case-by-case basis.  These comments pointed out that the automatic permanent closure of certain types of tanks was not appropriate after 12 or 24 months (for example, where nearby road construction has temporarily closed the business using the tanks).  In response to these comments, a provision has been incorporated allowing the implementing agency to approve an extension of the temporary closure period to address situations where permanent closure of an unprotected UST system is not appropriate after 12 months.  To ensure that the variance process is not used to postpone corrective action activities, however, the owner or operator must complete a site assessment before the extension can be applied for.

3.   Permanent Closure (§ 280.71)

	The proposed rule required the owner or operator of an UST to notify the implementing agency and assess the excavation zone at least 30 days before permanent closure.  Several of the commenters argued that completion of the site assessment at least 30 days prior to permanent closure was not always appropriate, for example, in cases where a tank is to be closed by removal or when closure is part of a corrective action.  In response to these valid comments, § 280.71(a) of the final rule has been revised to allow more flexibility by requiring the owner or operator to conduct an excavation zone assessment after notifying the implementing agency but before completion of permanent closure.  The final requirements continue to require notification at least 30 days before completion of premanent closure.  To avoid any potential conflict between the notification requirements of this section and the response requirements under the corrective action provisions, closures initiated as a result of corrective actions under Subpart F are not subject to the notification requirements in § 280.71(a) because the implementing agency will have already been notified as part of the corrective action activities.

	The methods for permanent closure were proposed in § 280.80(f) and the revised methods are set forth in § 280.71(b) in the final rule.  Emptying the tank by removal or filling with an inert solid material was a prerequisite for permanent closure under the proposed rule.  The term "empty," however, was not defined in the proposed rule.  In response to those commenters who argued that the amount of residual materials remaining in the tank system must be defined in order to minimize any future threat to human health or the environment, the final rule requires the tank to be "emptied and cleaned by removing all liquids and accumulated sludges."  In accordance with EPA's effort to build upon accepted industry consensus codes, a note following final § 280.71(c) identifies API 1604 and API 1631 as guidance on cleaning and closure procedures that may be used to comply with these requirements.  EPA believes that following these codes concerning the removal of regulated substances and cleaning of tanks before permanent closure will ensure human health and the environment are protected.  These codes also address the concerns expressed by a number of commenters regarding the disposal and reuse of tanks that have been removed from the ground.  Although not mandated in the final rules, adherence to the guidance in these codes concerning these activities will ensure the safe handling of tanks and will minimize the risk of releases during closure.

	The note following § 280.71(c) also contains a reference to the criteria issued by the National Institute for Occupational Safety and Health.  These criteria provide guidance concerning the prevention of deaths and injuries to workers involved in the assessment, decontamination, and cleanup of spills and leaks around underground storage tanks.  EPA suggests this code is particularly important to consider in the closure of hazardous substance tanks.

	The final rule continues to allow owners and operators to permanently close tanks by either removing the tank from the ground or filling the tank with an inert solid material.  Several commenters recommended that the rule require removal except when the tank is located under or immediately adjacent to other structures.  Their concerns focused upon the potential for releases of residual materials remaining in a tank after it is filled with inert fill and left in place.  EPA believes, however, that the final requirement concerning the removal of all liquids and accumulated sludges from the tank (required by § 280.71(b)) and use of the procedures outlined in API 1604 and API 1631 will adequately prevent the future release of residual material after a tank is filled.  Therefore, the final rule allows either method of permanent closure.

	Several commenters recommended further clarification of the meaning of "inert solid material."  The Agency believes that permanent closure in-place will adequately minimize the likelihood of future releases only if the inert fill material specifications and fill procedures used at closure are adequate to prevent the tank from surfacing after closure, will support the structural integrity of the tank as it deteriorates over time (to avoid cave-ins), and will completely seal the tank and associated piping from future use as a tank system.  However, the Agency has decided to not specify in detail the materials for filling a tank because of the numerous choices available and the special considerations and problems inherent in each.  Sand or concrete, for example, may restrict future construction activities on the site, or may complicate future removal and corrective action activities around the tank.  EPA believes that such decisions should be left to the owner and operator to make on a site-specific basis.

	EPA also agrees with the commenters who argued that the permanent closure requirements set forth in the proposed rule precluded the reuse of UST systems for unregulated substances.  As a result, sound tanks could be forceably discarded even though this would serve no environmental purpose.  Therefore, final § 280.71(c) gives owners or operators a third method of closing an UST system.  This method allows the owner or operator to complete a change-in-service, which will allow the tank to be used to store non-regulated substances.  To complete a change-in-service and avoid the other requirements under permanent closure, the implementing agency must be notified at least 30 days before the change-in-service is completed, and the tank must be cleaned and emptied by removing all liquids and accumulated sludges.  In addition, the owner and operator must assess the site in accordance with § 280.72.

4.   Assessing the Site at Closure (§ 280.72)

	The requirements for assessing the excavation zone around an UST system were proposed in § 280.80(d).  Several assessment methods were listed for satisfying these requirements, including the use of external monitoring release detection methods allowed under § 280.41.  Several commenters questioned the applicability of one or more of these methods in certain site-specific situations.  Some commenters suggested that other equally effective, methods may be appropriate, including internal release detection monitoring.  It was also suggested that the nature and extent of the excavation zone assessment should take into consideration various site-specific factors, many of which focused upon whether the tank is closed by removal or by closure in place.

	The final rule, as set forth in § 280.72, specifies minimum requirements necessary to adequately characterize the presence of contamination where it is most likely to be present at the UST site.  All of the methods listed in the proposed rule have been deleted except the use of external monitoring release detection methods, which continue to be allowed if they are operated in accordance with the final § 280.43 requirements at the time of closure.  Some of the other methods suggested by commenters, such as internal release detection monitoring, were not incorporated into the final rule because they do not monitor the condition of the environment outside the tank.  EPA remains convinced that this is an important last step before permanent closure is complete to ensure prior releases are not missed or ignored at closure like they have been in the past.

	Minimum assessment standards have been set forth in the final rule to coincide with the requirements set forth in Subparts E and F.  These standards are designed to ensure that assessment information is representative of the site's condition and is obtained before closure.  In order to be representative, the measurement methodology selected by the owner or operator must take into consideration factors such as the nature of the stored substance, type of backfill used around the tank, and the depth to ground water.  Any other factors must be considered that may be appropriate for identifying the presence and source of contamination from the UST system.  For example, soil gas sampling could be used if the regulated substance contains compounds that are highly volatile and if the local geology and hydrology do not significantly restrict the movement of the volatilized organic species.  However, if the regulated substance consists primarily of heavier hydrocarbons and, as a result, the concentration of vapors in the soil is expected to be very low, soil sampling may be needed to provide the necessary representative analytical results.

	The site assessment methodology used by the owner and operator must also consider the method of closure.  The two allowed tank closure methods may be treated differently because tanks that are removed from the ground enable the bottom of the excavation to be visually inspected.  A visual inspection of the tank and excavation zone should provide sufficient information for determining if and where the substances stored in the tank have leaked into the subsurface soil.  Using this information, a variety of sampling methods may be adequate to make an initial determination of the presence of contamination and the need for corrective action.

	On the other hand, the presence and size of leaks from tanks that are closed in place cannot be visually determined and, consequently, a more comprehensive assessment is necessary.  Therefore, several measurement methods may be required to determine if contamination is present around the tank.  For example, soil gas samples may be used to help identify where soil samples should be taken.  EPA believes that these changes will give the implementing agency greater flexibility to consider a variety of site-specific factors in defining the nature and extent of an assessment.  For example, although EPA believes that samples taken below an UST system will generally provide the most representative results, the final rule would allow samples to be taken at any depth or location.  However, a state inspection may determine that soil samples taken from the backfill surrounding a tank or soil gas samples taken at depths where significant volatilization has occurred may not be representative and additional testing could be required.

	The proposed rule in § 280.80(e) required the owner and operator to comply with the corrective action requirements if a release was discovered as a result of the activities conducted under any of the closure provisions or by any other manner.  As a result of comments that emphasized the inter - relation - ship between the corrective action provisions and the closure requirements, the Agency believes that the criteria for initiating corrective action during closure activities should be the same as the criteria for initiating corrective action at any other time during the operational life of an UST system.  The final rule sets forth these criteria in § 280.72(b).

5.   Applicability to Previously Closed UST Systems (§ 280.73)

	To address contamination threats expected to result from past closure practices, EPA proposed in § 280.80(d) that UST systems not properly closed in accordance with recommended industry practices before the effective date of the final regulation be revisited and properly closed.  The closure activities were to include a site assessment of the UST system, and notification to the implementing agency.  In addition; EPA proposed in this subsection to exept tanks that were previously closed in accordance with one of the existing industry consensus codes from these sites assessment requirements.  The Agency specifically requested comments on these previsions in the proposal.

	EPA proposed to apply the closure rules retroactively, recognizing that significant manpower and cost could be required to locate all previously abandoned tanks and to conduct site assessments.  To reduce this burden and focus only upon abandoned tanks that possed the greatest potential of leaking in the future, the proposed provisions were limited to tanks that had not been properly closed pursuant to one of the industry consensus codes in existence at the time.  Those consensus codes were believed to require only removal of the product stored in the tank.

	Upon review of numerous public comments received on this approach, it appears that the procedures used to close most abandoned tanks have not been well documented in the past, making it difficult to determine what constituted compliance with this requirement and whether a tanks was properly closed.  Moreover, several commenters argued that previous industry consensus codes were not designed to ensure containment of the material in the abandoned tank and may have actually facilitiated early releases due to the practice of punching holes in the bottom of the tank.  Thus, the commenters suggested that tank systems closed by using practices considered state-of-the-art at the time were just as likely to leak as those that were improperly closed.  It was also noted by severl commenters that the retroactive application of the closure provisions and imposition of site assessment requirements upon owners and operators of abandonned tanks would be costly to implement and would require the commitment of significant resources by the implementing agencies to track down and enforce.

	EPA now believes that many of the concerns raised by commenters are probably well founded if the requirements were applied to all USTs closed before the effective date of the regulations.  Such a "broad brush" approach would be very difficult, if not impossible, to enforce because of significant problems in locating the large number of tanks abandoned in the past, if not impossible, to enforce because of significant problems in locating the large number of tanks abandoned in the past, in identifying previous owners and operators, and in properly apportioning responsibility for the site assessment and closure activities.  As noted earlier, the lack of documentation would also make it difficult for the implementing agencies to determine if a tank had been "properly closed."

	EPA continues to believe, however, that a number of previously abandoned UST systems still contain regulated substances or may pose a threat to human health and the environment.  As discussed in the preamble of the April 17 proposal, state UST program incident reports examined by EPA revealed approximately 300 releases reported between 1970 and 1984 that implicated abandoned UST systems.  In addition, EPA expects more releases from the numerous operating USTs closed before the effective date of the notification requirements (May 8, 1986) and before the effective date of today's regulations.  Because there is a reasonable probability that releases from such tanks may pose a threat to human health and the environment, the application of the closure provisions to these tanks, and in particular the site assessment requirements, may be necessary and appropriate.

	EPA now believes that for tanks closed or abandoned before the effective date of today's regulations, the closure provisions should only be applied selectively under the discretionary authority of the implementing agency.  These agencies are in the best position to identify abandoned tanks that may have been improperly closed, and to gauge the nature and extent of the threat posed by those tanks.  They are also better able to identify the responsible owners and define the appropriate site assessment techniques.  This approach is intended to enable the implementing agencies to effectively allocate their resources and only focus upon abandoned tanks that are suspected of posing potentially significant problems.  This revised approach also reduces the unnecessary burden upon owners and operators of the discovered abandoned tanks by eliminating the requirement for them to revisit and conduct a site assessment at all tanks that have been previously closed, and removes the uncertainty associated with the "improper closure" standard.

	Therefore, the final rule deletes the proposed requirement to conduct site assessments at all tanks improperly closed before the effective date of the final regulations.  The final rule, however, requires owners and operators of abandoned tanks to comply with the closure provisions if so directed by the implementing agency when it determines there is a reasonable probability that the tank poses a potential threat to human health and the environment either now or in the future.

6.   Closure Records (§ 280.74)

	The recordkeeping requirements associated with closure were set forth in § 280.80(g) of the proposed rule.  These requirements have been reorganized in the final rule in § 280.74 but have not been significantly changed.  The principal change was the elimination of the reference to § 280.43 concerning the maintenance of release detection records.  Because these requirements are in § 280.70(a) of the final rule through the reference to Subpart D, and are thereby made applicable to all out-of-service and closed UST systems, repetition of the reference is not considered necessary.

H.	Analysis of Other Significant Comments

1.  Reliance on Codes Developed by Nationally Recognized Organizations

	As described in the preamble to the proposed rule (52 FR 12696), the regulations required that all UST systems be designed, constructed, and protected from corrosion in accordance with a code of practice developed by a nationally recognized association or independent testing laboratory.  In today's final regulations, the Agency has also included the use of industry codes for other technical sections of the rule (such as upgrading and repair of existing USTs).  The Agency has noted throughout today's final technical regulations specific codes of practice that have or may be developed.

	EPA did not receive any comments that were against or critical of the use of industry codes.  One commenter did express the need for public input during the development of federal technical regulations.  The Agency agrees that public participation is necessary for the development of sound industry codes and practices.  In fact, the Agency wants to expand the use of and reliance on industry codes in order to provide a means for improving existing or methods or developing alternative methods of UST system management.  EPA does not intend to adopt inadequate codes but wants to provide a flexible approach to codemaking by relying on nationally recognized organizations to develop new and improved codes and practices through a public process.

	EPA is today clarifying this issue to alleviate any future misunder - standings.  EPA interprets a "nationally recognized organization" to mean a technical or professional organization that has issued standards formed by the consensus of its members.  The organization should ensure consideration of all relevant viewpoints and interests, including those of consumers and future or existing and potential industry participants, and the resulting standards should be widely accepted and technically sound.  Thus, any code developed by an organization should be based upon a broad range of technical information, and performance crtieria should be central elements of the resulting standards.  EPA believes that the following organizations, which have codes and standards referenced in today's regulations, are examples of "nationally recognized organizations":

		American Petroleum Institute (API) 		Association of Composite Tanks (ACT) 		National Association of Corrosion Engineers (NACE) 		National Fire Protection Association (NFPA) 		National Leak Prevention Association (NLPA) 		Petroleum Equipment Institute (PEI) 		Steel Tank Institute (STI) 		Underwriters Laboratory (UL)

	Other similar organizations may also be considered 	"nationally recognized."

	The final rule does not require the use of a particular issue of any code.  The consensus codes are frequently revised and updated.  The Agency believes that requiring the use of "the most recent edition" would cause undue confusion in the regulated community.  For example, a facility may be installed in accordance with codes that are current at the time but may not have the equipment that meets the codes that are current 10 years later.  EPA has concluded that the industry codes that are in effect at the date of publication of the final rule are protective of human health and the environment.  The use of future editions of the codes in place of the editions that are now in effect is not required, but is encouraged as the updated codes will probably provide for newer, more effective technologies and practices.  The use of past codes that have been replaced by new editions by the effective date of this rule is not allowed because some past recommended industry practices were not fully protective of human health and the environment.

	The Office of Management and Budget has discussed regulatory codes and standards (OMB Circular A119, dated October 26, 1982).  OMB encourages the reliance on voluntary standards, commonly referred to as industry standards or consensus codes.  The developers of such codes are called voluntary standards bodies, and are defined to by OMB to include private sector, domestic, or multinational organizations--such as nonprofit organizations; industry associations, professional and technical societies, institutions, or groups; and recognized testing laboratories--that plan, develop, establish, or coordinate voluntary standards.  EPA interpretation of the phrase "nationally recognized organization" is intended to encourage the development and use of voluntary standards.

2.  Additional Decisionmaking Authority for Implementing Agencies

	As discussed elsewhere in today's FEDERAL REGISTER, EPA is promulgating requirements (in Part 281) for judging the stringency of state programs to be approved to operate in lieu of "the federal program."  Under Section 9004 of RCRA, the state program must contain specific program elements that are no less stringent that the corresponding federal technical requirements.  Instead of requiring a detailed line-by-line review and comparison of state requirements to federal technical requirements, EPA is today finalizing an approach to program approval that will compare state programs to the attainment of several general federal objectives that underlie the specific technical requirements provided in Part 280.

	In support of this approach, on December 23, 1987, EPA proposed to include additional language in the technical requirements that was intended to ensure this approval process is flexibly implemented (52 FR 48647).  In order to establish the federal objective for each program element, EPA requested comment on the addition of specific language into several sections of the technical standards that would clarify the Agency's intent to allow state implementing agencies to substitute their own procedural and administrative requirements for those set forth in the federal requirements.  Such administrative requirements, while essential for direct implementation of the federal program, do not represent the only possible approach for protection of human health and the environment, and thus are not part of the federal objectives for defining what requirements must be "no less stringent" under section 9004 of RCRA.

	Today's final technical standards include several of these wording changes proposed on December 23, 1987.  A list of the specific sections and the changes that have been made in the final rules are provided in Table 2.

	[INSERT TABLE 2 HERE]

	In general, the Agency decided to include this additional language in the final technical requirements to ensure that different state procedural and administrative approaches could be judged no less stringent than the corresponding federal program.  As discussed in more detail elsewhere in today's FEDERAL REGISTER, EPA has concluded that different state procedural and administrative requirements can be used and still achieve the underlying performance objective being established today for each program element.  It is the Agency's intent to allow the states a significant amount of discretion in this matter, as long as they can demonstrate that overall program performance in each program element will not be adversely impacted by their use of differing administrative practices and procedures.

	Many commenters were in favor of this more flexible approach to state program approval and most recommended the additional language be provided in the final technical rules to ensure a line-by-line review is avoided.  Other commenters exposed concern that additional language in the technical rules would encourage states to ignore the federal model.  Finally, one commenter opposed the flexible approach and stressed the Agency should "hold the line" in maintaining that states adhere to national regulatory decisions, even if only in procedural matters.

	EPA disagrees with those commenters who opposed the addition of implementing agency administrative discretion in the technical requirements.  They appeared to want to hold states to line-by-line comparisons to the federal program as the preferred way to determine if they are no less stringent.  Thus, they were generally opposed to the use of federal objectives for purposes of state program approval, as much as to the addition of greater discretion in the technical requirements that would ensure this approach could be implemented.

	As is discussed in the preamble to the state program approval regulation elsewhere in today's FEDERAL REGISTER, EPA has adopted the federal objectives approach to assessing states programs programs for purposes of state program approval.  Thus, the final technical standards rule also includes the proposed language providing additional authority to implementing agencies with respect to certain procedural or administrative requirements.

V.	RELATIONSHIP TO OTHER ASPECTS OF THE UST SYSTEM PROGRAM

A.	Interim Prohibition

	Section 9003(g) of RCRA Subtitle I sets forth requirements for tank systems installed between May 7, 1985, and 90 days after today's promulgation of final new tank performance standards.  During this period, UST may be installed unless it is corrosion protected, made of noncorrodible materials, or otherwise designed and constructed to prevent releases during the operating life of the facility due to corrosion or structural failure.  The tank material(s) of construction must also be compatible with the substance(s) to be stored.

	The final standards for new tank systems in today's rule (as discussed in section IV. of this preamble) are designed to replace the Interim Prohibition requirements.  These final performance standards address design, construction, installation, release detection, and compatibility for new tank installations.  The Interim Prohibition will, however, remain in effect by regulation for those tanks that have been deferred from coverage under the technical standards in Subpart A (e.g., some sumps, and field-constructed bulk tanks).

B.	Notification

	On November 8, 1985, EPA published the Final Rule on Notification Requirements for Owners of Underground Storage Tanks (50 FR 46602).  A form to be used for the required notification was included as part of the rulemaking.

	The UST rules and standards for new tanks promulgated today are not intended to affect these established notification requirements except to add to the information required to be submitted with the notification requirements (see section IV.B.).  These existing requirements have been recodified into § 280.22 of today's final rule.  Owners of existing UST systems were required to notify their designated state agencies by May 8, 1986.  Owners of new or replacement UST systems must notify their designated state agencies within 30 days of bringing the tank into use by submission of the November 8, 1985, federal form, or an approved alternate state notification form.

	Section 9002(a)(6) of RCRA requires that, beginning 30 days after the issuance of today's final new tank performance standards, any person who sells a tank intended to be used in an UST system must advise the tank purchaser of the owner's notification requirements.  This requirement is effective 30 days after publication of the new tank performance standards that are being promulgated today.  This requirement is codified in § 280.22(e) of today's rule.

C.	Leaking Underground Storage Tank Trust Fund

	Amendments to Subtitle I of RCRA enacted as part of the Superfund Amendments and Reauthorization Act of 1986 (SARA) provide for a Leaking Underground Storage Tank Trust Fund.  The amendments (Section 9003 (h)) provide funds for cleanup of petroleum spills from UST systems and give EPA, and states that enter into a cooperative agreement with EPA, the authority to respond to releases of petroleum from UST systems.  Almost all of the states have entered into these agreements with EPA and are now responding to petroleum releases from UST systems using Trust Fund revenues.  These amendments to RCRA were necessary because no other federal environmental program includes specific authority for response to releases of petroleum from UST systems, although releases of petroleum affecting navigable waters can be responded to under section 311 of the Clean Water Act.

	Section 9003(h) provides that the Administrator may issue an order requiring corrective action prior to the promulgation of today's final corrective action regulations under Subtitle I.  With the promulgation of today's requirements, the Administrator may use this same order authority, as well as the enforcement authority of section 9006, to require owners or operators to undertake corrective action.

	The Leaking Underground Storage Tank Trust Fund is being financed by taxes on motor fuels to pay for response costs in a limited set of circumstances.  Until the effective date of today's final technical standards (90 days after publication of today's rule), the Administrator, or states under cooperative agreements, may use the Fund to pay for a particular corrective action whenever the action is necessary to protect human health and the environment.  After that date, the statute provides for the use of the Fund primarily where the financial resources of the owners or operators are not sufficient to pay for the costs of corrective action, or if the owner or operator is otherwise unidentifiable, unwilling, or incapable of carrying out corrective action properly.  In some cases, an identifiable and solvent owner or operator may be in compliance with all UST financial responsiblity requirements (to be discussed in a later FEDERAL REGISTER Notice) but lack financial resources to pay the entire cost of a response.  In those cases, the Administrator or a state with a cooperative agreement is authorized to use the Fund to pay the costs that exceed the level of financial responsibility required of the owner and operator by the financial responsibility regulations.

	If the owner and operator has failed to maintain the required level of financial responsibility, the Trust Fund may not be used, unless:  (1) there is no solvent owner or operator; (2) there is an imminent and substantial threat to human health or the environment; or (3) there is a need to take corrective action outside the facility including the provision of alternative water supplies or relocation of residents.

	Ninety days after publication of today's regulations, cleanups under the Trust Fund must be conducted in accordance with the corrective action requirements (Part 280 Subpart G).

D.	Exempted Tank Studies

	The regulations finalized today do not apply to certain tank systems that were exempted by statute under section 9001 of Subtitle I.  Section 9009(d) and (e) of Subtitle I requires that EPA conduct a study of several of these systems and submit a report to Congress that includes recommendations as to whether these tanks should be regulated in the future.  The Report to Congress will be issued later this year.

	The Report to Congress will cover the following exempted tanks whose volume, including piping, is at least 10 percent belowground:

	oFarm or residential tanks of 1,100 gallons or less capacity used for storing motor fuel for noncommerical purposes, and

	oTanks used for storing heating oil for consumptive use on the premises where stored.

VI.	RELATIONSHIP TO OTHER AGENCY PROGRAMS

	This section discusses the relationship of today's final rules to certain other EPA regulatory programs.  This discussion is for informational purposes only.

A.	CERCLA

	Section 105 of the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA, or Superfund) requires development of a list of national priorities among known sites with releases and threatened releases of hazardous substances, pollutants, and contaminants.  The National Contingency Plan (40 CFR Part 300) regulates development of the National Priorities List (of sites with releases) as well as appropriate responses to the most serious releases.  These regulations currently apply to releases of CERCLA-designated hazardous substances from underground storage tanks.  CERCLA, however, does not apply to releases of petroleum from USTs or other sources.

	Releases of hazardous substances from UST systems may require removal or remedial action responses by federal or state agencies, in accordance with 40 CFR Part 300.  Some UST releases of hazardous substances are already included in the National Priorities List.  When today's final rules become effective (within 90 days), owners and operators of UST systems that release hazardous substances will be subject to the corrective action provisions of the rules and, in selected cases, the removal or remedial action measures of 40 CFR Part 300.  It is the responsibility of the owner and operator of a hazardous substance UST system that releases hazardous substances to consult with the implementing agency to determine the applicability of CERCLA requirements and Subtitle I release response and corrective action requirements under Subpart F.

	Under sections 102 and 103 of CERCLA, EPA has promulgated regulations (40 CFR Part 302) that identify hazardous substances and quantities of releases of these hazardous substances that must be reported to the National Response Center.  Those regulations contain reporting requirements for releases equal to or in excess of the established reportable quantities (RQs).  Under CERCLA, owners and operators of all kinds of storage, transportation, and disposal facilities containing hazardous substances must report releases to the National Response Center.  Owners and operators of USTs with releases of hazardous substances that exceed the RQs set forth in 40 CFR Part 302 will continue to be subject to those CERCLA reporting requirements.

	Under today's rule, owners and operators that store hazardous substances in USTs are also required to report spill or overfill releases of these substances from USTs that exceed the RQ to the implementing agency within 24 hours, or another period specified by the implementing agency, and immediately begin containment and cleanup of the release.  Owners and operators with spills or overfills of hazardous substances from USTs that are less than the reportable quantity will not be subject to the release reporting requirements although they will still be responsible to immediately contain and clean them up.

B.	Hazardous Waste Tank Program

	Under RCRA Subtitle C, EPA promulgated regulations for tank systems containing hazardous wastes (40 CFR Parts 264 and 265, July 14, 1986) including underground tanks.  The RCRA Subtitle I rules promulgated today apply to USTs containing "regulated substances."  These regulated substances include petroleum and hazardous substances defined in section 101(14) of CERCLA, except for hazardous wastes regulated under Subtitle C.  The exclusion of hazardous wastes from the definition of regulated substance avoids most of the overlapping jurisdiction of Subtitle I and Subtitle C.  An overlap in jurisdiction does exist, however, for USTs containing petroleum wastes that are subject to the provisions of RCRA 3014.  This overlap is discussed in the next section.

	There is also a potential overlap in jurisdiction for USTs containing mixtures of petroleum and hazardous wastes.  Today's final rules resolve this potential overlap by excluding such USTs from the universe of USTs subject to today's requirements.  Unless otherwise exempted, such USTs would be subject to the requirements of Subtitle C.  It is intended that today's rules regulate a different set of UST systems from those subject to regulation under Subtitle C.

C.	Hazardous Waste Management Regulations

	Section 3001 of the Resource Conservation and Recovery Act requires EPA to identify wastes that pose a hazard to human health and the environment if improperly managed.  Under the regulatory program established by Subtitle C of RCRA, EPA has developed a process that identifies and publishes lists of hazardous wastes.  Generators must determine whether their waste is on one of the lists in 40 CFR Part 261, Subpart D.  If a waste is not listed as a hazardous waste, waste generators are required to determine if their waste is hazardous either by testing it to determine if it exhibits any "characteristics," based on knowledge about the physical and chemical composition of the waste.  In the latter case, testing of the waste is not necessary if it is believed that it would not exhibit a hazardous waste characteristic.  The waste generator, however, remains responsible for making the correct determinations concerning the characteristics of reactivity, corrosivity, ignitability, and extraction procedure (EP) toxicity, as specified in 40 CFR Part 261, Subpart C.

1.  Hazardous Substances

	Many hazardous substances regulated by the Subtitle I tank rules are currently on EPA's hazardous waste lists of commerical chemical products at 40 CFR Section 261.33(e) and (f).  The products become hazardous wastes when discarded, including when spilled and then not cleaned up and used for their intended purpose.  Soils, water, or other debris contaminated by these products are subject to regulation as hazardous waste (see 40 CFR 261.33(d)).  A person removing such contaminated soil or debris during a cleanup is a hazardous waste generator, subject to Section 261.5 or Part 262.

2.  Petroleum and Petroleum-based Substances

	Petroleum-contaminated soils are not an EPA-listed hazardous waste.  Based on its physical and chemical nature, petroleum-contaminated soil would not exhibit the hazardous characteristics of corrosivity or reactivity under 40 CFR 261.  Some state UST programs have reported to the Agency that they require the use of the EPA tests for ignitability and EP toxicity to assist in making decisions about whether to manage th petroleum-contaminated soils on- or off-site.  Other states have simply declared that the soils are not a hazardous waste and, therefore, do not require testing or management as a hazardous waste.  Other states require management of petroleum-contaminated soils as a "special waste" that must receive special handling to control environmental and human health risks believed to be associated with the volatile organic chemical emissions known to come from such soils.

	Although some states require the use of the EPA tests, petroleum-contaminated soils do not satisfy the EPA criteria for an ignitable hazardous waste.  A substance is classified as a hazardous waste if it exhibits the characteristic of ignitability according to one of the following four criteria (40 CFR 261.21) as determined by using an ASTM or Administrator-approved testing procedures.  The substance must be:  (1) a liquid containing less than or equal to 24 percent alcohol having a flashpoint less than 140 F; (2) a nonliquid, but capable under standard temperature and pressure of causing fire through friction, absorption of moisture, or spontaneous chemical changes which burns so vigorously and persistently that it creates a hazard; (3) an ignitable compressed gas, as defined in 49 CFR 173.300; or (4) an oxidizer as defined in 40 CFR 173.151.  Gasoline-contaminated soils do not satisfy criteria (1), (3), or (4).  They do satisfy the nonliquid requirement of criterion (2); however, the Agency has concluded that they are very unlikely to ever be capable of causing fire by friction, absorption of moisture, or spontaneous chemical changes.  These soils, therefore, should not be a hazardous waste under Subtitle C of RCRA due to ignitability.

	Several states contacted by EPA reported that they have conducted thousands of EP toxicity tests on petroleum-contaminated soils and they have never exhibited the characteristic of EP toxicity at numerous sites nationwide where soils were contaminated by both leaded and unleaded gasolines.  This result is expected because the extraction procedure is designed to identify individual wastes that are hazardous due to their potential to leach significant concentrations of eight specific metals, four insecticides, and two herbicides in a municipal landfill scenario.  When subjected to the EP toxicity test, the only constituent of concern for soils contaminated by petroleum is lead.  The extremely high adsorption coefficient of lead, however, indicates that such soils are unlikely to ever exhibit the characteristic of EP toxicity.

	In summary, the evidence collected by or reported to the Agency to-date indicates it is very unlikely that petroleum-contaminated soils will be found to exhibit any of the characteristics of hazardous waste as currently defined by EPA regulations.  However, EPA is also aware that there are potential threats that need to be considered in the management of petroleum-contaminated soils.  For example, petroleum-contaminated soils (particularly motor fuels) can contribute significant amounts of volatile compounds to the air or be the source of dissolved contaminants (such as benzene) in ground-water resources.  Today's final regulations leave the off-site management of these concerns to existing state and local requirements.  EPA believes there are several ways to properly manage petroleum-contaminated soils that are not hazardous wastes, including the following approaches that are already being used in various states:

	oDefine petroleum-contaminated soils as a non-hazardous waste that requires disposal into permitted solid waste facilities.

	oDefine it as a special waste that requires special handling (such as land spreading, heat treating, or disposal in designated fill areas) that is tailored to remove the threats posed by the volatile constituents of the petroleum.

	oDefine petroleum-contaminated soils as a hazardous waste that must be treated or disposed of under the hazardous waste standards.

	EPA intends to study this technical issue further and provide more information to the public and the implementing agencies concerning alternative ways to manage petroleum-contaminated soils when they are managed on-site or removed off-site.  This information may include, for example, a description of different test methods that could be used to characterize petroleum-contaminated soils in a more meaningful fashion than present methods.  EPA is currently investigating techniques to measure and assess the condition of petroleum-contaminated soils, and handling and treatment alternatives that can be used to properly manage the potential risks they pose to human health and the environment.

	Finally, EPA notes that under proposed revisions to the toxicity characteristic under the Agency's hazardous waste regulations (40 CFR 261.24), benzene and a number of other compounds would be added to those constituents that, when measured in waste leachate, will determine whether a waste exhibits a hazardous waste characteristic.  (See 51 FR 21648; June 13, 1986.)  When these rule revisions are issued in final form, a large amount of petroleum-contaminated soils that are currently considered nonhazardous may have to be managed as hazardous waste.  For example, all petroleum-saturated soils may be characterized as a hazardous waste under the proposed revisions.  EPA is unsure of the impacts of this proposed rule change at this time, and in fact recently requested additional public comments on the levels for benzene and other constituents.  (See 53 FR 18024; May 19, 1988.)  However, the public comment period is closed on this issue.  The Agency will provide further guidance on this issue at a later date.

D.	Used Oil Regulations

	Underground tanks storing used oil (e.g., automobile and truck used crankcase oil) are under the jurisdiction of Subtitle I.  Pursuant to section 9001(2)(B) of RCRA, underground tanks containing "petroleum, including crude oil or any fraction thereof which is liquid at standard conditions of temperature and pressure . . ." are within the scope of Subtitle I.  Since used oil is primarily composed of petroleum, although it may contain contaminants due to use of the oil, it is subject to Subtitle I requirements.  Owners and operators of UST systems containing used oil were required to notify designated state agencies of the presence of such tanks by May 8, 1986.  Owners and operators of newly installed used oil UST systems have also been subject to the requirements of the Interim Prohibition, which has been in effect since May 8, 1985.

	As discussed above, however, today's regulations exclude any tanks regulated under Subtitle C of RCRA.  Under Subtitle C, EPA has the authority to regulate recycled oil, and to regulate used oil that is disposed of under Subtitle C if such oil is identified or listed as a hazardous waste.  Under the authority of Subtitle C of RCRA, EPA proposed to list used oil as hazardous waste (50 FR 49269-49270, November 29, 1985) and has proposed standards for recycled oil (50 FR 49250-49258, November 29, 1985).  Since those publications in the FEDERAL REGISTER, several important decisions in terms of these proposed rulemakings have been made, namely:

	(1) Storage of used oil (even when recycled) will be regulated, and

	(2) Recycled oil will not be listed as a hazardous waste (51 FR 41900, November 19, 1986).

	The storage of used oil, however, is not currently regulated as a hazardous waste under Subtitle C.  Unless and until the Agency regulates the storage of used oil as a hazardous waste under Subtitle C, it will be subject to Subtitle I.  Accordingly, the Agency is today including application of the technical requirements to used oil UST systems.  This is discussed in further detail in section IV.A.

E.	SPCC

	Under section 311 of the Federal Water Pollution Control Act, EPA has promulgated regulations for the prevention of oil spills into navigable waters.  These rules (40 CFR Part 112) known as the Spill Prevention Control and Countermeasure (SPCC) regulations are intended to prevent and contain releases of oil into surface waters which are navigable.

	Comparatively few UST systems are subject to SPCC regulations.  Only those tanks of greater than 42,000 gallons capacity that are located near navigable waters of the U.S. or adjoining shorelines may be affected.  UST systems which, due to their location, could reasonably be expected to discharge oil into or upon navigable waters of the United States or adjoining shorelines and which have a storage capacity greater than 42,000 gallons are subject to both today's rules and the SPCC rules.

F.	DOE High-Level Radioactive Waste Program

	Under the Atomic Energy Act of 1954 (42 U.S.C. 2001 et seq.), the U.S. Department of Energy (DOE) has promulgated rules for the management of high-level radioactive waste resulting from atomic energy defense activity.  DOE Orders 5480.1, 5480.2, and 5820.2 regulate the underground storage of these wastes, including corrective actions in the event of a release.

	The UST rules include the storage of radioactive waste because any radionuclide is a "hazardous substance" under CERCLA and thus a regulated substance under Subtitle I.  However, in view of the differences in high-level radioactive waste from other RCRA Subtitle I regulated substances and the much larger tanks storing this waste, EPA is today deferring regulatory action on these DOE radioactive waste facilities.  Until a determination is made as to whether, and how, the UST rules should apply to DOE facilities storing high-level radioactive wastes, today's UST requirements, except corrective action and the Interim Prohibition requirements, do not apply to these facilities.  More details are provided on this in section IV.A.

VII.	ECONOMIC AND REGULATORY IMPACTS

	Section VII.A. discusses the Regulatory Impact Analysis of the final rule required by Executive Order 12291.  Section VII.B. discusses the analysis of the effects of the final rule on small businesses required by the Regulatory Flexibility Act.  Section VII.C. addresses requirements under the Paperwork Reduction Act.  (A full draft of the Regulatory Impact Analysis for the final rule is available as part of the background documents supporting this rulemaking.)

A.	Regulatory Impact Analysis

1.   Executive Order 12291

	Executive Order 12291 (46 CFR 13193, February 19, 1981) requires regulatory agencies to conduct a Regulatory Impact Analysis (RIA) for any major rule.  EPA has conducted an RIA to assess the regulatory impacts of the technical standards rule for USTs based on the guidelines contained in the Office of Management and Budget's "Interim Regulatory Impact Analysis Guidance" and EPA's "Guidelines for Performing Regulatory Impact Analysis." The objective of the analysis is to examine the anticipated costs, benefits, and impacts of the final rule rather than to select a regulatory option.  Based on the results of the analysis, the Agency has concluded that the technical standards regulations being promulgated today represent a major rule that produces significant net benefits to society.

	As described in today's preamble, these technical standards pertain to tank system design, construction, and installation, leak detection, recordkeeping, reporting, closure, and corrective action.  For the proposed rule (52 FR 12761-12769), EPA conducted an RIA to compare several regulatory alternatives.  Each of these alternatives is discussed in detail in the "Regulatory Impact Analysis for Proposed Technical Standards for Underground Storage Tanks" (April 1987).  (This RIA for the proposed rule is contained in Appendix B of the RIA for the final rule.)  The RIA for the final rule does not consider various options.  Instead, it concentrates on the impacts of the provisions of the final rule (see sections III. and IV. of today's preamble for a full description of the requirements of the final rule.)

	The final rule refines the proposed rule (April 17, 1987) by phasing in requirements for release detection over a period of 5 years for existing tanks (based on the age of the tank) and by establishing more stringent requirements for pressurized piping.  Most of the other requirements in the final rule pertaining to corrosion protection and release detection are the same as in the proposed rule.

2.  Costs

	Compliance with the rule's requirements for release detection, system inspections and upgrading, and corrective action will require large expenditures by most UST owners and operators.  In addition, the large population of USTs means that the total costs for all USTs will be substantial from the standpoint of the economy as a whole.

	Table 3, column 2, displays the costs of the final rule for the entire UST population, by category of costs.  These cost estimates represent costs calculated using the UST Model, a model developed by the Agency to simulate the release and transport of petroleum products.  These estimates assume a total of 1.7 million USTs and a total of 30 years of costs after promulgation of the rule, discounted at a rate of 3 percent annually.  Based on EPA's analysis and assumptions, the estimated cost of the final rule is expected to be approximately $69 billion over a period of 30 years, or $3.6 billion per year (discounted at a rate of 3 percent).

	[INSERT TABLE 3 HERE.]

	In order to evaluate the incremental costs of the final rule, EPA estimated the costs that would be incurred by UST owners and operators in the absence of any further regulations.  These costs are presented in column 1 of Table 3 as base case cost.  Subtracting the base case costs from the costs under the final rule yields the incremental cost of the final rule, shown by cost category in Table 3, column 3.  This incremental cost is expected to be approximately $48 billion over 30 years, or $2.5 billion on an annual basis (discounted at an annual rate of 3 percent).  The administrative costs of implementing the final rule are not included in this analysis.

3.  Benefits

	The final rule's requirements for leak detection and prevention and corrective action will provide society with a variety of benefits.  The benefits are defined as reductions in damages under the rule in comparison to the base case.  Two kinds of damages are considered in the RIA:  those that occur before a release is detected, such as contamination of private and public wells; and those that occur after a release is detected, such as contamination of soil and ground water.

	The pre-detection damages are $2.1 billion under the final rule, and $4.8 billion in the base case.  The incremental benefits of regulation resulting from this decrease in pre-detection damages are therefore $2.7 billion.  The post-detection damages are estimated to be $52.8 billion under the base case, and negligible under the final rule.  (Under the final rule, corrective actions must be performed as soon as a release is detected which accounts for this drastic reduction in post-detection costs.)  The incremental benefits of regulation resulting from a decrease in post-detection damages are therefore $52.8 billion.  The total incremental benefits of the rule, including the benefits from reduction in both pre- and post-detection damages, are $55.5 billion ($2.7 billion due to reduction of pre-detection damages and $52.8 billion due to reduction of post-detection damages).  The yield in benefit for each UST is about $31,000.

	EPA believes that, in addition to the benefits summarized above, many additional benefits of release detection and prevention cannot be expressed quantitatively or in purely monetary terms.  Examples of these important benefits include the prevention of added risks to human health, the value of preventing damage to the ability of streams to support life, and the basic value of preventing contamination of ground-water resources whether or not they are currently being used.

	In an attempt to provide some measure of these benefits, EPA has quantified the health benefits of the release detection, prevention, and corrective action portion of the final rule, but has expressed the benefits in terms of cancer cases avoided and the reduction in numbers of USTs posing cancer risks in excess of a specified threshold (Table 4).  Of the two scenarios shown in Table 4, one scenario assumes that people will not use water that smells or tastes badly.  The other scenario assumes that people will use water whether it seems contaminated or not.

	[INSERT TABLE 4 HERE.]

4.  Cost Effectiveness of the Final Rule

!viia4a!	A comparison of the incremental costs of the final rule to its incremental benefits is shown in Figure 6.  The figure shows the incremental costs of the final rule to be $48.9 billion, which include repair, system upgrading and replacement, release detection, and corrective action for the entire population of 1.7 million USTs.  In contrast, the incremental benefits of the rule are estimated to be $55.5 billion.  These benefits consist largely of reductions in damages occurring after releases are detected, but also include reductions in well and vapor damages and lost product occurring before the detection of releases.  By subtracting costs from benefits, the net dollar benefits of the final rule over the next 30 years are estimated to have a present value of $6.6 billion, or $4,000 per UST.  In addition to the benefits measured in dollar terms, the rule also significantly reduces damages to human health and the environment.

	[INSERT FIGURE 6 HERE.]

5.  Economic Impacts on Existing Facilities

	An economic impact analysis was performed for the general industry and retail marketing sectors having petroleum USTs and for firms having hazardous substance USTs.  The results of this analysis indicate that firms in the retail motor fuel marketing sector would be most adversely affected, for several reasons:  they have a greater number of small firms that are more vulnerable to significant regulatory expenditures; regulatory expenditures in this sector are likely to be greater because motor fuel retail outlets generally have the greatest number of USTs per outlet; and firms in the retail motor fuel marketing sector do not have the option of closing their USTs and using alternative storage methods.  The RIA reaches the following conclusions:

	oBy year ten, 43 percent more small firms are projected to close under the final rule than in the base case.

	oMost economic impacts of the final rule occur in the first 5 years after its imposition.

	oMost closures of existing outlets are caused by corrective action expenses.

	oWere corrective action to be performed in the base case as well as under the final rule, the model predicts that a higher percentage of outlets would survive under the final rule than in the base case.

6.  Integration of Technical Standards and Financial Responsibility Rules

	EPA prepared separate RIAs for the proposed technical standards and financial responsibility rules in order to estimate the costs and economic impacts of each proposed rule.  As many commenters pointed out, a major weakness of this approach was that the two RIAs could not easily be used to assess the combined impacts of the proposed technical standards and financial responsibility rules to construct an "after regulation" picture of the regulated community.  Commenters also noted that certain indirect costs that would be imposed on the regulated community were not included in either RIA.  They explained that in order to buy insurance to satisfy the financial responsibility requirements, UST owners and operators would have to upgrade their USTs by installing release detection systems sooner than required by the technical standards rule.

	In response to these comments, EPA has revised its approach in preparing the RIAs for the final rules, so that the two RIAs now perform the following functions:

	oAccount for the indirect costs of having to upgrade tank systems sooner to procure financial assurance; and

	oEstimate the combined costs and economic impacts of both sets of requirements.

	The RIA for the financial responsibility rule assumes the technical standards rule in its base case in order to estimate its costs and economic impacts.  The costs incurred in upgrading, replacing, retrofitting, and corrective action are attributed to the technical standards rule.  Costs incurred to upgrade sooner than required by the technical standards rule in order to obtain financial assurance are attributed to the financial responsibility rule.  By using the technical standards rule as the base case and computing the incremental costs of the financial responsibility rule, the overall costs to the regulated community can be estimated properly.

B.	Regulatory Flexibility Act

	Under the Regulatory Flexibility Act of 1980 (5 U.S.C. 601 et seq.), agencies publishing a proposed or final rule must prepare and make available for comment a Regulatory Flexibility Analysis that describes the potential impact of the rule on small entities (i.e., small business, small organizations, and small government jurisdictions).  The purpose of the Regulatory Flexibility Act is to ensure that regulations do not impose unnecessary costs or other burdens on such entities.  As part of its RIA, EPA has examined the potential impact of today's rule on small entities and has concluded that the rule will have a significant impact on a substantial number of small entities, as described below:

1.  Small Entities Potentially Affected by the Rule

	The Agency divided the businesses potentially affected by the rule into three categories:  firms engaged in retail motor fuel marketing (e.g., gasoline service stations), firms engaged in other businesses (general industry category), and local government entities.  EPA focused the emphasis of the Regulatory Flexibility Analysis on the retail motor fuel marketing sector because (1) all firms in this sector must store their product in underground storage tanks; (2) about three-quarters of all retail motor fuel outlets are owned or operated by small businesses; and (3) the data base for this sector is reasonably accurate and will capture the most severe small-business impacts likely to occur as a result of the rule.

a.	Small Businesses in the Retail Motor Fuel Marketing Sector

	For this Regulatory Flexibility Analysis, small businesses in the retail motor fuel marketing segment are defined as firms with less than $4.6 million in annual sales and include all firms with only one or two outlets.  Firms with $4.6 million in sales will typically have approximately $500,000 in assets and a net worth of about $250,000.  EPA estimates that in 1984, small businesses either owned or operated 72 percent of the 193,000 retail motor fuel outlets in the United States.

	To examine the rule's potential economic impact on small businesses, EPA estimated the rates at which existing firms in the retail motor fuel marketing sector would leave the industry with and without regulations.  For the purposes of this analysis, EPA estimates that these outlets have historically tended to exit the industry at a rate of 3 to 4 percent per year.  If releases occur at the level estimated by the RIA and no revenue increases are possible for small businesses, this rate would increase to 6.2 percent per year, assuming average corrective action costs.

b.	Small Businesses in the General Industry Sector

	An estimated 24 to 41 percent of all USTs in the general industry sector are owned by firms with less than $1 million in assets.  A typical small firm in this segment was assumed to have $300,000 in assets and net profits of $21,000 a year.  Overall, these firms represent about 12 percent of all UST-owning firms in the general industry sector.

	The cost of corrective action for non-plume release (i.e., no ground-water contamination) would leave a small general industry firm in severe financial distress, and the cost of corrective action for a plume release (i.e., contamination of ground water) would lead to the failure of the firm.  Replacing a tank would cause a small general industry firm a temporary financial hardship; however, this hardship would not seriously threaten the survival of the firm.

c.	Small Local Government Entities

	Local government entities of all sizes own USTs.  In 1982, the typical municipality with a population less than 50,000 had general revenues of $1.7 million.  The costs of replacing even a single UST would represent 2 percent of the revenue of such a municipality, a significant expenditure that would have to be taken into account when planning.  A corrective action that required cleaning up a dispersed plume would represent more than 13 percent of the general revenues of such a community, a sum that would probably cause severe financial distress.

	In 1982, of the 38,886 local governments classified as counties, municipalities, and townships, 37,581 (approximately 97 percent) had populations of 50,000 or less.  Almost all UST-owning local governments would, therefore, be subject to potentially substantial economic impacts under the technical standards rule if an UST release occurred.

C.	Paperwork Reduction Act

	The information collection requirements in this rule have been approved by the Office of Management and Budget (OMB) under the Paperwork Reduction Act, (44 USC 3501 et seq.) and have been assigned OMB Control Number 2050-0068.  Reporting and recordkeeping burden on the public for this collection is estimated at 8,265,220 hours for the 1,750,000 respondents, with an average of 4 hours per response.  These burden estimates include all aspects of the collection effort and may include time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information.

	If you wish to submit comments regarding any aspect of this collection of information, including suggestions for reducing the burden, or if you would like to a copy of the information collection request (please reference ICR #1360), contact Rick Westlund, Information Policy Branch, PM-223, U.S. Environmental Protection Agency, 401 M Street, S.W., Washington, D.C. 20460<PHONE_NUMBER>); and Marcus Peacock, Office of Information and Regulatory Affairs, Office of Management and Budget, Washington, D.C.  20503.

VIII.  LIST OF SUBJECTS IN 40 CFR PART 280

	Administration practice and procedures, Confidential business information, Ground water, Hazardous materials, Reporting and recordkeeping requirements, Underground storage tanks, Water pollution control, Water supply.

                                   Lee Thomas Administrator