Top Takeaways From 2019 Proposed Amendments to the MCP

MassDEP leadership has recently shared that they expect the next set of Amendments to the Massachusetts Contingency Plan (MCP), proposed in 2019, to be promulgated soon. In an effort to refresh our collective memories, the LSPA Regulations Committee has prepared this brief, high-level summary of eight key aspects of the proposed MCP regulations. The summary provided below is based on the draft revisions provided in 2019. The LSPA has not seen a more recent draft. The actual contents of the forthcoming MCP revisions are not known.

Hot Spot and MGP Waste Definitions 
The 2019 proposed amendments include the addition of Manufactured Gas Plant (MGP) Waste as a defined term. Additionally, the amendments propose modifying the definition of a hot spot to include areas of waste disposal including MGP waste. These proposed changes effectively create a new class of oil and hazardous material (OHM), with concomitant requirements for sampling and risk assessment.

EPC Derivations/Calculations
The 2019 proposed amendments embody more prescriptive requirements for calculating Exposure Point Concentrations (EPCs). Specifically, the use of the arithmetic average will no longer be an acceptable method for estimating the EPC for soil, except in the case of a discrete source of localized contamination. Otherwise, the 95th percentile upper confidence limit must be used. Maximum values could still be used for screening-style assessments

Additional regulatory requirements may include the use of a systematic sampling approach to obtain a representative data set unless there is technical justification for not doing so. Such justification would have to consider the distribution and variability of the contamination and the size of the area sampled.

Tier Classification Requirements
The 2019 proposed amendments provide that Tier Classification Extensions may expire after one year. 

Post-TS Reporting and Tier Classification Requirements
In addition to the 5-year periodic evaluation, an annual status report will be required for sites which have achieved a Temporary Solution (TS). Submittal of the annual status report will have the effect of maintaining a Tier Classification Extension. For Sites currently in Temporary Solution, it is unclear when the first annual status report will be due and how PRPs will be notified. 

Selection of Remedial Action Alternatives (RAAs)
When a Permanent Solution is not selected as an RAA for the entire disposal site, the evaluation of feasible RAAs must include alternatives to reduce OHM exposure to achieve a Permanent Solution at a portion of the disposal site.

AEPMM (Active Exposure Pathway Mitigation Measures) Revisions
The proposed amendments include expanding definitions to include positive pressurization systems as well as additional requirements for AEPMMs that must be implemented to support a Permanent Solution including minimum monitoring, telemetry, and operational requirements.

Terminology Conflict: Upper Confidence Limit vs Upper Concentration Limit
The proposed amendments include that Upper Concentration Limit will likely be modified to “Method 3 Ceiling Limit” or “Ceiling Limit” for short.

Climate Change Provisions
The proposed amendments reference climate change in the definition of Conceptual Site Model; at 310 CMR 40.1005(1) related to "'Foreseeable Period of Time' for Purposes of a Permanent Solution"; and again at 40.0191: Response Action Performance Standard (RAPS). The assessment of potential climate change impacts are to be based on information available by the state. 

For those wishing a deeper dive into the proposed regulations, please read the LSPA’s July 19, 2019, cover letter as well as the LSPA’s detailed matrix of comments and suggestions on the full proposed MCP amendments. 

Once MassDEP releases the next set of MCP Amendments, the LSPA will be providing members with more detailed summaries of key changes, outstanding questions, compliance tips, and other information. Stay tuned!

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