1. A. Purpose and Scope. This regulation:

   1. (1) Establishes requirements with which a hazardous waste generator must comply in connection with the permanent removal from service, for the purposes of hazardous waste management, of:

      1. (a) An area in which hazardous waste was accumulated in a manner that was subject to the requirements of this chapter, other than accumulation in a satellite accumulation area;
      2. (b) A waste management unit, such as a tank, used to manage hazardous waste in an accumulation area described in §A(1)(a) of this regulation; and
      3. (c) A site or facility that had an area or waste management unit of the type described in §A(1)(a) or (b) of this regulation;
   2. (2) Establishes a general closure performance standard that a hazardous waste generator must meet for all hazardous waste accumulation areas and hazardous waste management units identified in §A(1) of this regulation;

   3. (3) Identifies specific requirements that must be met in implementing closure, including requirements:

      1. (a) That apply to all types of accumulation units; and
      2. (b) Specific to particular types of accumulation units; and

   4. (4) Identifies:

      1. (a) Record keeping requirements with respect to closure; and
      2. (b) Closure notification requirements that apply to a generator who qualified as a federally-defined large quantity generator for significant periods of time.

2. B. Closure Requirements.

   1. (1) Applicability. The general closure performance standard and other requirements of this section:

      1. (a) Apply to an area or waste management unit in which hazardous waste was managed, as described in §A(1)(a) of this regulation; and

      2. (b) Apply to a site or facility that had an area or waste management unit identified in §A(1)(a) of this regulation and at which the generator:

         1. (i) Will no longer be generating or accumulating hazardous waste; or
         2. (ii) Is ceasing operations entirely;

      3. (c) May be deferred for an accumulation area or unit if the generator anticipates that the area or unit may again be used to accumulate hazardous waste, if the:

         1. (i) Notification requirements of Regulation .05-2 of this chapter are met; and
         2. (ii) Closure performance standard and other requirements of this section are met before the facility is closed.

   2. (2) General Closure Performance Standard. A generator shall ensure that, if a hazardous waste accumulation area, a hazardous waste management unit, or a facility or site at which hazardous waste was generated or accumulated is closed by being permanently removed from service for the purposes of hazardous waste management:

      1. (a) The closure is conducted in a manner that minimizes the need for further maintenance by controlling, minimizing, or eliminating, to the extent necessary to protect human health and the environment, the post-closure escape of hazardous waste, hazardous constituents, leachate, contaminated runoff, or hazardous waste decomposition products to the ground, to ground water, to surface water, or to the atmosphere; and

      2. (b) Any hazardous waste that is generated in closing the generator’s facility or a portion of the facility is managed in accordance with all applicable requirements of:

         1. (i) This chapter, including, for hazardous waste that is being accumulated in a unit that is being closed, accumulation time limits of Regulation .03-4C of this chapter;
         2. (ii) Chapters .04 and .06 of this subtitle; and
         3. (iii) 40 CFR Part 268.

   3. (3) Additional Unit-specific Closure Requirements for Container, Tank System, and Containment Building Accumulation Units. For the closure of a hazardous waste accumulation unit in which hazardous waste was managed in a container, a tank system, or a containment building:

      1. (a) The generator shall ensure that closure of the unit provides, to the extent necessary to meet the general closure performance standard of §B(2) of this regulation, for the removal or decontamination of:

         1. (i) All contaminated equipment, structures, and soil, and any remaining hazardous waste residues from waste accumulation units, including containment system components such as pads or liners;
         2. (ii) Contaminated soils, subsoils, bases, and structures; and
         3. (iii) Structures and equipment contaminated with waste; and

      2. (b) If the generator is unable to practicably remove or decontaminate contaminated soils or wastes as required by §B(3)(a) of this regulation, then the waste accumulation unit is considered to be a landfill for the purposes of closure, post-closure, and financial responsibility, and the generator shall:

         1. (i) Close the waste accumulation unit and perform post-closure care in accordance with the closure and post-closure requirements of COMAR 26.13.05.14J, which apply to landfills;
         2. (ii) Meet all of the requirements for landfills specified in COMAR 26.13.05.07 and 26.13.05.08; and
         3. (iii) Submit a complete and sufficient application to the Department for a CHS post-closure permit in accordance with a deadline to be specified by the Department.

   4. (4) Unit Specific Closure Requirements for Drip Pads. At the closure of a drip pad waste accumulation unit, as defined in COMAR 26.13.01.03B, the generator shall:

      1. (a) Comply with the closure requirements of COMAR 26.13.05.17-4A—C; and
      2. (b) If required to close the facility and provide post-closure care as a landfill, in accordance with COMAR 26.13.05.17—4B, submit a complete and sufficient application to the Department for a CHS post-closure permit in accordance with a deadline to be specified by the Department.

   5. (5) Closure Plan. A generator who is closing a waste accumulation area, waste accumulation unit, or facility under this regulation shall:

      1. (a) Perform the closure in accordance with a written closure plan;

      2. (b) Ensure that the closure plan includes:

         1. (i) A description of how the requirements of §B(2)—(4) of this regulation will be met in performing the closure, taking into account the nature of facility operations and the history of any spills or releases of hazardous wastes;
         2. (ii) A detailed description of the steps needed to remove or decontaminate all hazardous waste residues and contaminated containment system components, equipment, structures, and soils during closure, including, but not limited to, procedures for cleaning equipment and removing contaminated soils, methods for testing surrounding soils, and criteria for determining the extent of decontamination required to satisfy the closure performance standard; and
         3. (iii) A detailed description of other activities necessary during the closure to ensure that closure activities satisfy the closure performance standard, including, but not limited to, groundwater monitoring, and run-on and runoff control; and

      3. (c) For each implemented closure action:

         1. (i) Maintain, as part of the generator’s facility operating record, a copy of the written closure plan that was followed in implementing the closure;
         2. (ii) Make a copy of the written closure plan available to the Department on request; and
         3. (iii) Retain a copy of the written closure plan for a period of 3 years following the date of final closure of the facility.

Authority: Environment Article, Title 7, Subtitle 2, Annotated Code of Maryland

Effective date:

Regulations .01—.07 adopted as an emergency provision effective November 18, 1980 (7:25 Md. R. S-1); adopted permanently effective April 3, 1981 (8:7 Md. R. 642)

Regulations .01; .04A, D; .05D, E; .07B amended effective January 18, 1982 (9:1 Md. R. 20)

Regulations .01B; .02B; .04A, B, D; .05E; .06A—C; and .07A amended, and .01G and .04E adopted effective July 30, 1984 (11:15 Md. R. 1330)

Regulations .01E and .05E amended effective February 13, 1984 (11:3 Md. R. 202)

Regulations .01F, .04D, .06C, and .07A amended effective January 31, 1983 (10:2 Md. R. 110)

Regulation .05E amended effective August 12, 1985 (12:16 Md. R. 1607)

Chapter recodified from COMAR 10.51.03 to COMAR 26.13.03

Regulation .01B, D amended effective August 28, 1995 (22:17 Md. R. 1321)

Regulation .01G amended effective December 23, 1991 (18:25 Md. R. 2759)

Regulation .01H and I adopted effective April 18, 1988 (15:8 Md. R. 1009)

Regulation .02A amended effective December 23, 1991 (18:25 Md. R. 2759)

Regulation .04 amended effective April 18, 1988 (15:8 Md. R. 1009); September 11, 2006 (33:18 Md. R. 1507)

Regulation .04A, C amended effective December 23, 1991 (18:25 Md. R. 2759)

Regulation .04A, D, E amended effective May 24, 1993 (20:10 Md. R. 853)

Regulation .05 amended effective September 11, 2006 (33:18 Md. R. 1507)

Regulation .05C amended effective December 23, 1991 (18:25 Md. R. 2759)

Regulation .05E amended effective April 18, 1988 (15:8 Md. R. 1009); May 24, 1993 (20:10 Md. R. 853); September 10, 1997 (24:5 Md. R. 413)

Regulation .06A amended effective May 5, 1997 (24:9 Md. R. 659)

Regulation .06B amended effective April 18, 1988 (15:8 Md. R. 1009); December 23, 1991 (18:25 Md. R. 2759); August 28, 1995 (22:17 Md. R. 1321); May 5, 1997 (24:9 Md. R. 659)

Regulation .06C amended effective September 11, 2006 (33:18 Md. R. 1507)

Regulation .07A amended effective April 18, 1988 (15:8 Md. R. 1009)

Regulation .07 repealed and new Regulations .07 and .07-1—.07-4 adopted effective August 28, 1995 (22:17 Md. R. 1321)

Regulation .08 repealed effective May 5, 1997 (24:9 Md. R. 659)

Chapter revised effective October 16, 2000 (27:20 Md. R. 1843)

Regulation .01B-1 adopted effective November 1, 2002 (29:21 Md. R. 1647)

Regulation .01G amended effective May 1, 2008 (35:8 Md. R. 809)

Regulation .01J adopted effective May 1, 2008 (35:8 Md. R. 809)

Regulation .02 amended effective November 1, 2002 (29:21 Md. R. 1647)

Regulation .04 amended effective September 11, 2006 (33:18 Md. R. 1507)

Regulation .04A amended effective May 1, 2008 (35:8 Md. R. 809)

Regulation .05E amended effective May 1, 2008 (35:8 Md. R. 809)

Regulation .07 amended effective November 1, 2002 (29:21 Md. R. 1647)

Regulation .07A amended effective May 1, 2008 (35:8 Md. R. 809)

Regulation .07-1 amended effective November 1, 2002 (29:21 Md. R. 1647)

Regulation .07-2A amended effective September 11, 2006 (33:18 Md. R. 1507)

Regulation .07-2C amended effective November 1, 2002 (29:21 Md. R. 1647)

Regulation .07-3 amended effective September 11, 2006 (33:18 Md. R. 1507)

Regulation .07-5 adopted effective November 1, 2002 (29:21 Md. R. 1647)

Chapter revised effective May 3, 2021 (48:9 Md. R. 359)

Regulation .01A-2 amended effective October 1, 2025 (52:17 Md. R. 876)

Regulation .01D amended effective January 13, 2022 (49:1 Md. R. 14)

Regulation .01G amended effective October 1, 2025 (52:17 Md. R. 876)

Regulation .01K, L adopted effective October 1, 2025 (52:17 Md. R. 876)

Regulation .01-1B-1 adopted effective October 1, 2025 (52:17 Md. R. 876)

Regulation .02C amended effective October 1, 2025 (52:17 Md. R. 876)

Regulation .03-3E amended effective October 1, 2025 (52:17 Md. R. 876)

Regulation .03-4C amended effective October 1, 2025 (52:17 Md. R. 876)

Regulation .03-5C amended effective October 1, 2025 (52:17 Md. R. 876)

Regulation .03-7B amended effective October 1, 2025 (52:17 Md. R. 876)

Regulation .04 amended effective January 13, 2022 (49:1 Md. R. 14)

Regulation .05F adopted effective October 1, 2025 (52:17 Md. R. 876)

Regulation .05-4C amended effective October 1, 2025 (52:17 Md. R. 876)

Regulation .06B amended effective October 1, 2025 (52:17 Md. R. 876)

Regulation .06C amended effective January 13, 2022 (49:1 Md. R. 14)

Regulation .07 repealed and new Regulation .07 adopted effective January 13, 2022 (49:1 Md. R. 14)

Regulations .07-1—.07-3 repealed effective January 13, 2022 (49:1 Md. R. 14)

Regulation .07-4 amended effective January 13, 2022 (49:1 Md. R. 14)

Regulations .07-5 repealed effective January 13, 2022 (49:1 Md. R. 14)