Section 20-6206. RISK-BASED CORRECTIVE ACTION (RBCA) PROGRAM

 

6206.1Risk-based decision-making (RBDM) and development of a risk-based corrective action (RBCA) plan shall be conducted subject to the terms and conditions set forth in this section and/or as further explained in applicable UST Division protocols and the Risk-Based Decisionmaking Technical Guidance Document.

 

6206.2Before initiating a risk-based decision-making process to develop a risk-based corrective action plan for petroleum releases, a responsible party shall comply with §§ 6203 and 6204 as follows:

 

(a)Prevent further release from the UST system by removal of all or a lesser amount of the petroleum products from the UST system and/or perform repairs to the UST system;

 

(b)Remove measurable free product to the maximum extent practicable;

 

(c)Achieve the upper concentration limit (UCL) for benzene in groundwater as specified in § 6210.

 

6206.3The following sequence of actions comprises the District's RBCA process:

 

(a)Perform an Initial Site Assessment, including identification of potential exposure pathways, take response action(s) as set forth in § 6203 and submit a work plan;

 

(b)Complete site classification as defined in Chapter 70;

 

(c)Complete Tier 1 site assessment pursuant to the comprehensive site assessment provisions set forth in § 6205 and as further described in the Risk-Based Decisionmaking Technical Guidance Document;

 

(d)Compare the concentrations of Chemicals of Concern with Tier 1 risk-based screening levels provided in § 6209;

 

(e)If the concentrations exceed Tier 1 screening levels, develop and implement corrective action plan (CAP) to achieve Tier 1 levels or proceed to perform Tier 2 site-specific evaluation as described in the Risk-Based Decisionmaking Technical Guidance Document;

 

(f)Collect additional site-specific information, as necessary for development of Tier 2 site-specific target levels, perform fate and transport analysis, including modeling, to determine points of compliance; apply for and obtain variances for soil or water quality standards if necessary; and

 

(g)Develop and implement a corrective action plan (CAP) to achieve the site specific target levels or monitor for compliance.

 

6206.4For purposes of risk-based corrective action (RBCA) in the District of Columbia:

 

(a)The Chemicals of Concern (COC) shall include the following petroleum products or by-products:

 

(1)For gasoline: benzene, toluene, ethylbenzene and xylenes (BTEX); Methyl tertiary-Butyl-Ether (MtBE); and gasoline range organics (GRO).

 

(2)For light distillate oils including kerosene, Jet A and JP #s 4, 7 and 8, Naphthalene and diesel range organics (DRO).

 

(3)For diesel, heating fuels and used oils: DRO and Naphthalene;

 

(b)The Point of Compliance (POC) shall be:

 

(1)For Tier 1 assessment:

 

(a)At the point of release or in the source area;

 

(b)Groundwater, affected by the contaminant plume including any areas of the plume that are outside of the property boundary in accordance with UST Division protocols and the Risk-Based Decisionmaking Technical Guidance Document; and

 

(c)Soil, throughout the area of the soil contaminated by the release and within the property boundary.

 

(2)For Tier 2 assessment, the point between the source and the potential point of exposure as approved by the Director.

 

(c)For residential development of property, the maximum tolerable human health risk for carcinogens shall be one-in-a-million cancer risk level (that is, the criteria represent a one-in-a-million estimated incremental increase in cancer risk over a lifetime). For non-carcinogenic health affects, the hazard quotient and hazard index shall be no greater than "1".

 

(d)The Tier 0 standards and the Tier 1 standards shall be as set forth in §§ 6208 and 6209, respectively.

 

(e)The exposure routes shall include ingestion of groundwater or soil; dermal contact with surface water or soil; and inhalation of volatiles.

 

(f)For exposure pathways, points of exposure shall include groundwater, surface water, and soil; and transport media shall include leaching to groundwater and soil gas migration into buildings.

 

6206.5The Risk-Based Decisionmaking Technical Guidance Document shall include or address existing and new UST Division protocols, specific procedures including Tier 0, Tier 1 and Tier 2 RBCA assessment and evaluation procedures, Chemicals of Concern, upper concentration limit criteria, analysis procedures including use of modeling, equations, sampling, corrective action procedures and monitoring requirements for implementation of risk-based corrective action and other explanatory information in accordance with the minimum requirements of this section no later than one (1) year after the effective date of these regulations. UST Division protocols shall continue to provide guidance until the issue of the Risk-Based Decisionmaking Technical Guidance Document.

 

6206.6If levels of chemicals of concern exceed the Tier 1 standards set forth in § 6209, the responsible party may:

 

(a)Submit a CAP pursuant to § 6207 to achieve the Tier 1 levels; or

 

(b)Conduct a Tier 2 site specific evaluation following the procedures and protocols for Tier 2 evaluations contained in the Risk-Based Decisionmaking Technical Guidance Document; or

 

(c)Comply with the provisions of § 6206.2.

 

6206.7After completion of the RBCA process, the responsible party may apply for a no-further-action or case closure, as appropriate, pursuant to the requirements of § 6211.

 

source

Final Rulemaking published at 40 DCR 7835, 7889 (November 12, 1993); as amended by Final Rulemaking published at 46 DCR 7699 (October 1, 1999).