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B-20 Remedial Investigation Report for Former Open Burn/Open Detonation Area
Section 3 - Regulatory Framework
The closure investigation of the B-20 former OB/OD area is being considered in compliance with an EPA Compliance Order to CSSA dated June 30, 1993. The Compliance Order required that CSSA, the operator of the B-20 area, immediately cease operation of the unit and prepare and implement a closure plan for the unit in accordance with applicable regulations. This section presents the regulatory framework applicable to closure of the B-20 site.
In November 1980, CSSA submitted a RCRA Part A permit application for hazardous waste management activities at the facility. The facility was then granted interim status to operate as a hazardous waste facility under RCRA. The B-20 former OB/OD area was not included as a hazardous waste management unit in the Part A permit application, or in subsequent hazardous waste activity notifications. CSSA had ceased operations at the B-20 site at the time of the Part A application and did not resume demolition activities until 1984. From the 1950s or 1960s until 1987 (with a hiatus in activities from 1980 through 1983, and in 1985, as stated previously), CSSA used the B-20 site to treat and dispose of reactive waste explosives. Explosives are classified as hazardous wastes under RCRA based on the characteristic of reactivity (EPA waste number D003). The disposal of wastes in this unit resulted in the B-20 area being designated as a solid waste management unit (SWMU). During an inspection in January 1993, EPA determined that the B-20 SWMU was also a hazardous waste thermal treatment unit and did not have interim status since it was not included in the Part A permit application. A subsequent EPA Compliance Order issued in June 1993 required CSSA to prepare and implement a closure plan for the B-20 SWMU site. This compliance order and all subsequent correspondence with regulatory agencies regarding the B-20 site are included as Appendix D.
Based on the nature of its operation, the B-20 site is considered a thermal treatment unit (40 CFR 265 Subpart P) by state regulators. As a hazardous waste treatment unit, the B-20 site is regulated under both federal and state regulations. The EPA Compliance Order for the B-20 unit required that the closure plan be prepared in accordance with 40 CFR 265 Subpart G and 30 TAC Chapter 335 (formerly Title 31).
3.2 - Closure Performance Standard
The regulations which specify closure requirements for interim status hazardous waste facilities are established in 40 CFR Part 265 Subpart G, as adopted in 30 TAC 335 Subchapter E. These regulations establish the closure performance standards, post closure requirements, and financial assurance requirements. Since the B-20 site is a RCRA-regulated unit, all RCRA interim status closure requirements must be met.
In accordance with 40 CFR 265.111, adopted by reference in 30 TAC 335.112, closure of this unit must be designed and implemented to accomplish the following:
Minimize the need for further maintenance.
Control, minimize, or eliminate, to the extent necessary to protect human health and the environment, postclosure escape of hazardous constituents, leachate, contaminated runoff, or hazardous waste decomposition products to groundwater or surface waters or to the atmosphere.
Ensure compliance with the specific closure requirements established for this unit.
This closure performance standard will be achieved at the B-20 site by implementing the standards specified in the State of Texas risk reduction rules (30 TAC 335 Subchapter S).
3.3 - Applicable State Regulations
The state regulations governing industrial solid wastes and municipal hazardous wastes and pertinent to this unit closure are established in 30 TAC Chapter 335 Subchapters A, E, and S. Rules outlined in Subchapter S are also known as the risk reduction rules.
The closure requirements in 30 TAC 335 Subchapters A and S apply to closure of both industrial solid waste and municipal hazardous waste sites. The closure regulations establish the obligation for closure and remediations, and specify the mechanisms to evaluate those closures and remediations. In addition to the closure and remediation requirements outlined in 30 TAC 335 (risk reduction standards), any treatment, storage, or disposal facility is also subject to the provisions in subchapter E, which incorporate 40 CFR 265 by reference.
Risk reduction standards established in 30 TAC 335 Subchapter S apply to closure and remediation of solid waste management units (including hazardous waste management units). These regulations define three closure standards based on the level of risk posed by residual contamination left on site after the completion of all site closure activities:
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Risk reduction standard 1 is the equivalent of clean closure and requires that all waste constituents at the site be removed to background levels. Post closure care and deed recordation are not required under standard 1. |
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Risk reduction standard 2 requires that all waste constituents at the site be removed to health-based levels that eliminate any substantial current or future risks to human health or the environment. Deed recordation information must be filed, but post-closure care is generally not required. |
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Risk reduction standard 3 allows for the use of engineering controls to achieve protection of human health and the environment. An investigation and risk assessment must be performed for the site. The cleanup criteria are then based on the site specific information. Post-closure care and deed recordation are required. |
For all three standards, a final report to the Executive Director is required to show that the closure meets criteria established in 30 TAC 335. If closure is conducted under standard 2, the site must be deed recorded with local authorities. Furthermore, if closure is conducted under standard 3 and post-closure care is determined necessary, a post-closure care plan must be prepared and implemented, and the site must be deed recorded.
In March 1994, the closure plan for the B-20 site, which was prepared in accordance with 40 CFR 265.112 detailing closure activities consistent with 30 TAC 335 Subchapter S, was submitted to the EPA Administrator for review. Although this plan was entitled "Closure Plan," it is considered to be a notification of closure (communication with Mr. Cecil Irby, TNRCC Industrial and Hazardous Waste Section, Federal Facilities Corrective Action Team, August 9, 1994). The final plan for site closure will be developed when sufficient analytical data is available to determine closure standards and any corrective measures for the site. The notification of closure detailed the initial plan of action to be taken towards closure of the B-20 site. Comments on the "notification of closure" made by EPA are included in Appendix D.