Scope and Types of Immediate Response Actions

(1) At a minimum, Immediate Response Actions shall involve the assessment of the release or threat of release and/or site conditions described in 310 CMR 40.0412. The nature and extent of assessment actions taken as an Immediate Response Action shall be commensurate with the type and amount of oil and/or hazardous material released or threatening to be released, site complexity, and the sensitivity of site and surrounding human and environmental receptors, and shall be adequate and sufficient for determining: (a) the degree of hazard posed by the release, threat of release and/or site conditions; (b) whether remedial actions are required at the site prior to the completion of a Phase IV Remedy Implementation Plan, as described in 310 CMR 40.0870; and (c) where appropriate, the nature, extent, and timing of anyrequired removal or containment actions. (2) Immediate Response Actions shall be presumed to require the initiation of one or more containment or removal actions. Except as provided in 310 CMR 40.0414(3) through 40.0414(5), the presumption for containment and/or removal actions may be rebutted, however, by the RP, PRP or Other Person conducting response actions, based upon a showing by a preponderance of the evidence that: (a) the release, threat of release and/or site conditions do not present an Imminent Hazard, either at the present time or for the time period that is likely to be required for the implementation and/or completion of Comprehensive Response Actions; and 40.0414: continued (b) the unmitigated migration of oil and/or hazardous material at the site, at present and for the time period that is likely to be required for the implementation and/or completion of Comprehensive Response Actions, is not likely to: 1. substantially increase the extent, area, or magnitude of environmental contamination; 2. substantially increase the degree or complexity of future remedial actions; 3. substantially increase cleanup costs; or 4. otherwise result in a substantial hazard to health, safety, public welfare or the environment. (3) Immediate Response Actions shall be presumed to require the elimination and/or mitigation of Critical Exposure Pathways, which are defined in 310 CMR 40.0006. This presumption may be rebutted, however, by the RP, PRP or Other Person conducting response actions, based upon a showing by a preponderance of the evidence that: (a) the Critical Exposure Pathway(s) does not present an Imminent Hazard, either at present or for the time period that is likely to be required for the implementation and/or completion of Comprehensive Response Actions; (b) it is not feasible to eliminate the Critical Exposure Pathway(s); and (c) in cases where it is not feasible to eliminate the Critical Exposure Pathway(s), it is not feasible to mitigate the Critical Exposure Pathway(s). (4) Immediate Response Actions shall be presumed to require the prevention and/or mitigation of Critical Exposure Pathways, which are defined in 310 CMR 40.0006. This presumption may be rebutted, however, by the RP, PRP or Other Person conducting response actions, based upon a showing by a preponderance of the evidence, that: (a) the Critical Exposure Pathway(s) does not present an Imminent Hazard, either at present or for the time period that is likely to be required for the implementation and/or completion of Comprehensive Response Actions; (b) it is not feasible to prevent the Critical Exposure Pathway(s); and (c) in cases where prevention is not feasible, it is not feasible to mitigate the Critical Exposure Pathway(s). (5) Immediate Response Actions shall be presumed to require the prevention of impact(s) to public water supplies at sites where such impact is likely to occur within the time period that is likely to be required for the implementation and/or completion of Comprehensive Response Actions. This presumption may be rebutted, however, by the RP, PRP or Other Person conducting response actions, based upon a showing by a preponderance of the evidence that: (a) it is unlikely that the site will present impact(s) to the public water supply, for the time period that is likely to be required for the implementation and/or completion of Comprehensive Response Actions; (b) it is not feasible to prevent the impact(s) to the public water supply; and (c) in cases where prevention is not feasible, it is not feasible to mitigate the impact(s) to the public water supply. (6) Immediate Response Actions may include: (a) preparation of technical reports or memoranda documenting why accelerated removal or containment actions are or are not required; (b) an assessment of whether an Imminent Hazard to health, safety, public welfare or the environment exists at the site; (c) collection and assessment of soil, sediment, surface water, groundwater, soil gas, or atmospheric or indoor air samples; (d) assessment of the validity of underground storage tank testing results; (e) assessment of the need to take timely actions to prevent releases from occurring at a site where a threat of release has been identified; (f) installation of fences, warning signs, including, where appropriate, multilingual and symbolic signs, and/or the institution of other security or site control measures; (g) installation of drainage controls; (h) construction or stabilization of berms, dikes or impoundments; (i) temporary covering or capping of contaminated soils or sludges; (j) installation of waste or product recovery and groundwater treatment systems or soil vapor extraction systems; 40.0414: continued (k) removal of contaminated soils; (l) removal of the contents of, or removal of, drums, barrels, tanks or other bulk containers which contain or may contain oil and/or hazardous material; (m) temporary evacuation or relocation of residents from the site and/or surrounding area; (n) provision of temporary alternative water supplies; (o) installation of a sub-slab soil gas depressurization system beneath an occupied structure; or (p) any other assessment, containment or removal action consistent with the purpose and scope of an Immediate Response Action or otherwise deemed necessary by the Department. (7) A permanent cap or Engineered Barrier that is constructed in accordance with the performance standards contained in 310 CMR 40.0998 as an Immediate Response Action will not be considered part of a Permanent Solution at a disposal site, unless and until a Phase III is performed pursuant to the provisions of 310 CMR 40.0850 demonstrating the lack of a feasible alternative.