1. A. In addition to the UST system requirements in Regulation .02 of this chapter, an owner and an operator of a hazardous substance UST system shall:

   1. (1) Provide containment that meets the requirements of this regulation; and
   2. (2) Monitor the containment systems using interstitial monitoring pursuant to Regulation .05G of this chapter at least monthly.

2. B. An owner and an operator of a hazardous substance UST system shall ensure the hazardous substance UST system meets the following requirements:

   1. (1) A secondary containment system is designed, constructed, and installed to:

      1. (a) Contain hazardous substances spilled or released from the primary containment until the spill or release is detected and removed;
      2. (b) Prevent the spill, release, or discharge of hazardous substances to the environment at any time during the operational life of the UST system; and
      3. (c) Be checked for evidence of a spill, release, or discharge at least monthly;

   2. (2) A double-walled UST is designed, constructed, and installed to:

      1. (a) Contain a release from any portion of the inner storage tank within the outer wall; and
      2. (b) Detect the failure of the inner wall;

   3. (3) An external liner, including a vault, is designed, constructed, and installed to:

      1. (a) Contain 100 percent of the capacity of the largest UST within its boundary;
      2. (b) Prevent precipitation or groundwater from entering the liner; and
      3. (c) Surround the UST completely;
   4. (4) Underground piping is equipped with secondary containment that satisfies the requirements of §B(1)—(3) of this regulation; and
   5. (5) Underground piping that conveys hazardous substances under pressure is equipped with an automatic line leak detector in accordance with Regulation .02D(2) of this chapter.

3. C. An owner and an operator of hazardous substance UST system may use other methods of release detection in conjunction with interstitial monitoring as required in §A(2) of this regulation if the owner and an operator of the UST system:

   1. (1) Demonstrates to the Department in writing that an alternate method can detect a release of the stored hazardous substance as effectively as any of the methods allowed in Regulation .05B—H of this chapter,
   2. (2) Provides the Department with information regarding effective corrective action technologies, health risks, and chemical and physical properties of the stored hazardous substance, and the physical characteristics of the regulated substance storage facility; and
   3. (3) Obtains approval from the Department to use the alternate release detection method before the installation and operation of the UST system.

Authority: Environment Article, §§4-401, 4-402, 4-405, 4-407—4-411.2, 4-415.1, 4-417, 4-701 et seq., and 7-201 et seq., Annotated Code of Maryland

Effective date: February 4, 1991 (18:2 Md. R. 151)

Chapter revised effective November 4, 1996 (23:22 Md. R. 1498)

Regulation .01 amended effective February 18, 2002 (29:3 Md. R. 224)

Regulation .01A amended effective January 12, 2009 (36:1 Md. R. 25)

Regulation .02B amended effective June 29, 1998 (25:13 Md. R. 997)

Regulation .02C amended effective January 16, 2006 (33:1 Md. R. 39)

Regulation .02D amended effective January 12, 2009 (36:1 Md. R. 25)

Regulation .04 amended effective January 12, 2009 (36:1 Md. R. 25)

Regulation .04B amended effective June 29, 1998 (25:13 Md. R. 997)

Regulation .04C amended effective February 18, 2002 (29:3 Md. R. 224); January 16, 2006 (33:1 Md. R. 39)

Regulation .06 amended effective January 16, 2006 (33:1 Md. R. 39)

Regulations .01—.06 repealed and new Regulations .01—.06 adopted effective June 13, 2022 (49:12 Md. R. 642)