This entry was posted in environmental. Bookmark the permalink. Follow any comments here with the RSS feed for this post.


Update Changes in the MCP

By Daniel G. Jaffe, MS, LSP

environmental changes

The DEP is getting closer to promulgating the proposed changes in the Massachusetts Contingency Plan (310 CMR 40.0000).  Some of the more significant changes involve Tier Classification, Exposure Pathway Mitigation, Non-Aqueous Phase Liquid (NAPL), and Response Action Outcome (RAO) Statements.


Tier Classification:

One of the most significant changes is in Tier Classification, where the Numerical Ranking Scoresheet (NRS) will be replaced with four criteria, including:

1) the site’s location within an area with groundwater classified as RCGW-1 and/or in a GW-1 area;

2) the presence of an Imminent Hazard (IH);

3) an ongoing Immediate Response Action (IRA) being conducted to address a Critical Exposure Pathway (CEP); and

4) an IRA with ongoing remedial actions.

The presence of any of these conditions would result in a Tier 1 Classification, although there would be grandfathering of current Tier 2 sites where IRA’s to address CEP’s, or IRA’s with remedial actions are already underway prior to effective date.


Active Exposure Pathway Mitigation Measure:

Active mitigation measures, such as subslab depressurization systems (SSDS) will be able to be accomplished as as part of a “Permanent Solution with Conditions”, utilizing an “Activity & Use Limitation” (AUL), but would not require a permit.  Specific conditions and requirements would apply, including remote telemetry (i.e. monitoring of the system); and notifying affected parties in buildings if a shutdown extends beyond 30 days.


Non-Aqueous Phase Liquid (NAPL):

A Permanent Solution may be applicable even with the presence of NAPL, as long as there is an absence of Non-Stable NAPL; and NAPL removal has been performed to the extent feasible.  However, an AUL would be required if NAPL is present.


Response Action Outcome (RAO) Statements:

There will no longer be RAO Statements, only

“Permanent Solutions With Conditions” and Permanent Solutions With No Conditions”.  A “Condition” could include the implementation of an “Activity & Use Limitation” (AUL); but other conditions, which do not require an AUL may include “Anthropogenic Background” (i.e. historic fill material); “Gardening Best Management Practices” (whose definition will be added); areas under roadways and rail rights-of-way; and areas with groundwater contamination above GW-2 standards, but in areas with no current or planned occupied buildings.

Both comments and trackbacks are currently closed.