Connecticut DEEP seeks to Overhaul Remediation Standards – Groundwater VOC Volatilization Criteria and Transition Provisions

On July 8, 2019 the Connecticut Department of Energy and Environmental Protection (“DEEP”) proposed an overhaul to its Remediation Standard Regulations (“RSRs”). These proposed amendments, often referred to as “Wave 2, ” will significantly alter Connecticut’s remediation programs if they are approved. DEEP is seeking public comments on these proposed regulatory changes through October 7, 2019, and will be hosting public information sessions in July, August and September.

Because DEEP’s regulatory changes are so sweeping, their scope cannot be captured in a single Alert. Therefore, for the next several weeks, Pullman & Comley’s Environmental Practice Group will be issuing a series of Alerts, each one focusing on one aspect of the changes to the RSRs.


If you have a Connecticut property where groundwater is contaminated with volatile organic compounds (VOCs), the “Wave 2” proposals will be of urgent interest because they set significantly more stringent volatilization criteria. But you’ll want to pay just as much attention – perhaps more – to provisions that would give you a limited opportunity to achieve compliance using current criteria.

The proposed “Wave 2” changes concerning VOCs affect the default criteria, expressed as numerical contaminant concentrations, by which the Remediation Standard Regulations (RSRs) define “how clean is clean.” The criteria are found in a series of appendices concerning contaminants in soil (direct exposure and pollutant mobility), groundwater (surface water protection, volatilization), and soil vapor (volatilization).**[1] Since adoption of the RSRs in 1996, these criteria have remained largely unchanged even though the RSRs contemplate periodic review of protectiveness “at intervals of no more than five years.” RCSA §22a-133k-1(e). Continuing this pattern, “Wave 2” would leave most criteria in place.

The most significant exception involves groundwater volatilization criteria, for which “Wave 2” proposes dramatic reductions – including several that are lower by an order of magnitude. For example, the RSR volatilization criteria currently set a limit of 50,000 ppb for methylene chloride, a common furniture-stripping chemical, in both residential volatilization criteria and industrial/commercial settings; the proposed values are 160 ppb and 2,200 ppb respectively. Less striking but still significant are the proposed reductions for the common solvents trichloroethylene (current 219/540, proposed 27/67) and tetrachloroethylene (current 1,500/3,820, proposed 340/810). Despite a handful of instances where proposed criteria are higher, these examples are fairly representative of proposed criteria that are predominantly more stringent.

The other significant aspect of the “Wave 2” proposed groundwater volatilization criteria involves potential exposure as a result of vapor intrusion. RSR volatilization criteria have always included a factor based upon proximity to structures – specifically, that the criteria apply to groundwater “within fifteen feet of the ground surface or a building.” RCSA §22a-133k-3(c)(1). Under the “Wave 2” proposal, this proximity factor will remain the same for a new subcategory of “volatile petroleum substances” (“VPS”), defined as VOCs “found in gasoline, diesel fuel, fuel oil, heating oil, kerosene, jet fuel, or similar fuels,” as well as VOCs employed as fuel additives. But for a new category of “volatile organic substances” (“VOS”), defined as all VOCs that are not VPS, the proximity factor will increase from fifteen to thirty feet. Independent of the new numerical criteria, this change will significantly expand the reach of the volatilization criteria.

These much more stringent criteria are noteworthy in themselves. The proposal also provides for a transition period, however, during which compliance may be measured by current criteria – but only at properties that have progressed to a specified stage in the sequence of site investigation, remedial design, and remedial action when the “Wave 2” changes go into effect.

This transitional treatment would not employ the current criteria in their entirety. Rather, it would permit remediation using either the current fifteen-foot proximity factor, or the current numerical criteria. See “Wave 2” proposal §22a-133k-1(j)(1). In other words, opting for the existing fifteen-foot factor would require use of the new, more stringent numerical criteria, and opting for the existing numerical criteria would require use of the new, more stringent thirty-foot proximity factor, at least for VOCs in the new VOS subcategory.

The option would moreover be available only if all of the following conditions are satisfied:

  • Before the “Wave 2” revisions take effect, VOC remediation has been initiated, or an LEP has determined that no VOC remediation is required and that determination has been documented in a Remedial Action Plan already submitted to DEEP, and public notice of remediation has been published, if required.
  • Remediation of VOCs is completed within twenty-four months after the “Wave 2” revisions take effect, sufficient to support LEP verification or DEEP approval.
  • Documentation of compliance with these provisions is submitted to DEEP within five years after the “Wave 2” revisions take effect, or in compliance with Transfer Act deadlines, whichever is earlier.
  • Compliance has been achieved with all other groundwater VOC requirements.

The first three of these conditions involve milestones tied to the effective date of the “Wave 2” revisions. When will that be? Difficult to say. Publication of proposed regulations on July 8, 2019, opened a comment period scheduled to close on October 7, 2019. DEEP will review and report on comments and deliver proposed final regulatory language, which will then undergo multiple levels of administrative review going to the General Assembly’s Legislative Regulatory Review Committee for final approval. DEEP hopes this process can be concluded, and the “Wave 2” proposals issued as final rules, by 2020.

For present purposes, the first of the foregoing conditions (“remediation initiated”) is key. The option to use current criteria or the current fifteen-foot proximity factor will be available only if groundwater remediation for volatilization criteria has been initiated (or deemed unnecessary) by the time the revisions take effect.

As a practical matter, if you own property with VOCs in groundwater, you should review the current and proposed VOC volatilization criteria, and track the progress of the proposed changes. If you think your path to closure is easier under the current criteria or proximity factors, then you should move your site investigation and remedy selection activities forward as needed to meet the “remediation initiated” condition when the “Wave 2” changes take effect.

For more information on DEEP’s changes to the Remediation Standard Regulations, please contact any member of our Environmental Practice Group, your responsible Pullman Attorney or send a message to  If you prefer, you may investigate this initiative further on DEEP’s website.


[1] The RSRs also contain an appendix of numerical “Target Indoor Air Concentrations,” but their function is not to define cleanup standards as such. Rather, they serve as inputs in calculating site-specific residential volatilization criteria for groundwater and soil vapor. See RCSA §22a-133k-3(c)(4)(A) (authorizing calculation); Appendix G (formulas and variables for calculation including Target Indoor Air Concentration values).

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