D.C. Mun. Regs. tit. 20, r. 20-6203

Current through Register Vol. 71, No. 52, December 27, 2024

Rule 20-6203 - SITE INVESTIGATION, CONFIRMATION OF RELEASE, INITIAL ABATEMENT, AND INITIAL SITE ASSESSMENT

6203.1

When a release, or leak into the interstitial area of a secondarily contained system, is suspected, a responsible party shall conduct tightness testing in accordance with §§ 5902.7, 6004.8, and 6007 to determine whether:

(a) A leak exists in the portion of the tank that routinely contains a regulated substance or in the attached delivery piping; or

(b) A breach of either wall of the secondary containment has occurred.

6203.2

If the tightness test confirms a leak into the interstitial area or a release, the responsible party shall repair, replace, upgrade, or close the UST system, and begin corrective action in accordance with this chapter.

6203.3

The responsible party may use the UST system to store regulated substances before completing corrective action only if the source and cause of the leak or release has been identified and remedied.

6203.4

A responsible party shall also conduct a site investigation, as set forth in §§ 6203.5 through 6203.7, if:

(a) The tightness test results for the system, tank, or delivery piping indicate that a release has occurred; or

(b) The environmental contamination detected by visual or analytical data indicates that a release has occurred.

6203.5

When conducting a site investigation, the responsible party shall test for the presence of a release where contamination is most likely to be present at the UST site.

6203.6

In selecting the sample types, sample locations, and measurement methods for a site investigation, the responsible party shall consider the nature of the stored substance, the type of initial alarm or cause for suspicion, the type of backfill, the depth of groundwater, the presence of a basement sump pump, and other factors appropriate for identifying the presence of a released substance and the source of the release. The responsible party shall comply with any Department directives, available on the Department's website at https://doee.dc.gov/page/ust- forms-guidance-and-public-documents, regarding sample types, sample locations, measurement methods, and sampling protocols.

6203.7

If the sample results of the site investigation do not confirm that a release has occurred, no further investigation is required.

6203.8

Upon discovery of a release or confirmation of a suspected release, a responsible party shall perform the following initial response actions:

(a) Immediately identify and mitigate any fire, explosion, and vapor hazards;

(b) Take immediate action to prevent any further release of the regulated substance into the environment;

(c) If the notification under § 6202 was of a suspected release or condition listed in § 6202.5, notify the Department by telephone or e-mail and the District Fire Chief, as stated in § 6201.2, no later than twenty- four (24) hours after confirmation of the release or of a false alarm; and

(d) Submit a written report containing the information required in § 6202.3 to the Department, in accordance with § 5500.4, within seven (7) days of discovery or confirmation of the release.

6203.9

Section 6203.8 does not apply to any UST system exempt from the UST regulations under § 5501.3, or to any UST system subject to the corrective action requirements under § 3004(u) of the Solid Waste Disposal Act, 42 USC § 6924(u), as amended.

6203.10

Upon discovery of a release or confirmation of a suspected release, a responsible party shall take the following initial abatement actions:

(a) Remove all regulated substance from the UST, unless the Department approves removal of a lesser amount that is sufficient to prevent further release to the environment ;

(b) Visually inspect any aboveground releases or exposed belowground releases and prevent further migration of the released substance into surrounding soils and groundwater; and

(c) Continue to monitor and mitigate any fire and safety hazards posed by vapors or free product that have migrated from the excavation zone and entered into subsurface structures (such as sewers or basements).

6203.11

A responsible party shall remedy hazards posed by contaminated soils that are excavated or exposed as a result of site investigation, release confirmation, abatement, or corrective action activities. If the remedy includes treatment or disposal of soil, the responsible party shall comply with all applicable provisions of District laws and regulations, including 21 DCMR Chapters 5, 7, 8, and 20.

6203.12

Upon discovery of a release or confirmation of a suspected release, a responsible party shall conduct an initial site assessment that evaluates conditions within the property boundaries of the property where the UST is located, and prepare an initial site assessment report summarizing the results, which includes the following actions:

(a) Unless the presence, source, and cause of the release have been confirmed in the site investigation required by § 6203.4 or the closure assessment in § 6101.10, test for the presence of a regulated substance by taking soil borings and by installing groundwater or soil vapor monitoring wells where contamination is most likely to be present at the UST facility;

(b) In selecting the sample types, sample locations, and measurement methods to test pursuant to § 6203.12(a), consider the nature of the stored substance, the type of backfill, depth to groundwater, and other factors as appropriate for identifying the presence and source of the release;

(c) Analyze and summarize the levels of contaminants in the soil borings and groundwater samples;

(d) Summarize the initial response actions taken pursuant to § 6203.8; and

(e) Summarize the initial abatement actions taken pursuant to § 6203.10.

6203.13

Upon discovery of a release or confirmation of a suspected release, a responsible party shall determine whether free product is present. If any phase of the site investigation determines that free product is present, the responsible party shall begin free product removal as soon as practicable in accordance with § 6204.

6203.14

Within sixty (60) days after release confirmation, a responsible party shall submit to the Department, in accordance with § 5500.4, an initial site assessment report prepared pursuant to § 6203.12 for review, and if applicable, include the first status report on the removal of free product. If further assessment is needed to determine the nature and extent of contamination from the release, the responsible party shall submit a work plan for comprehensive site assessment, in accordance with § 6205, for the Department's approval. A responsible party may request a meeting with the Department to discuss the work plan.

6203.15

For purposes of this section, the phrase "aboveground release" means a release to the surface of the land or to surface water, including a release from a portion of an UST system above the ground surface or a release associated with a transfer of a regulated substance to or from an UST system.

6203.16

For purposes of this section, the phrase "belowground release" means any release to the subsurface of the land and to groundwater, including a release from the portion of an UST system below the ground surface or a belowground release associated with a transfer of a regulated substance to or from an UST.

D.C. Mun. Regs. tit. 20, r. 20-6203

Final Rulemaking published at 40 DCR 7835, 7886 (November 12, 1993); as amended by Final Rulemaking published at 46 DCR 7699 (October 1, 1999); amended by Final Rulemaking published at 67 DCR 1778 (2/21/2020)