MCP Amendments Information Webpage and Method 3 Shortform Corrections

The LSPA received the following email from MassDEP's Bureau of Waste Site Cleanup on Friday. 

Dear Waste Site Cleanup Program stakeholder,

Information related to the 2024 amendments to the Massachusetts Contingency Plan, effective March 1, 2024, is posted on the “MCP Amendments” webpage on MassDEP’s website at On this webpage you will find redlined and clean versions of the 2024 MCP amendments, summary of the changes, MassDEP’s response to comments, and related implementation materials. MassDEP intends to continue to add supporting materials related to the amendments to this page as they become available.

Note regarding Recent Corrections to the Updated Method 3 Shortforms

Updated Shortforms for Method 3 Human Health Risk Assessments first posted to the “MCP Amendments” webpage on 11/13/23 were taken down on 12/4 after MassDEP found a toxicity value error. After further review, toxicity value errors were identified and corrected for Fluoranthene, Indeno(1,2,3-cd)pyrene, Styrene and Trichloroethylene. The corrected Shortforms have now been reposted. You may access them from the “MCP Amendments” page or directly at  

A description of the corrections made are contained in the “12-13-23 revision note.pdf” in the Shortforms. That description is also provided below. 

12-13-23 Description of Shortform Revisions

The following revisions were made to the toxicity file for the Shortforms (v1223) on December 13, 2023. These revisions address data entry errors and rounding inconsistencies.

    • Fluoranthene: the chronic RfC was changed to 0.05 mg/m3 (from 1E-1, a data entry error) which makes the value consistent with that used in the derivation of the Method 1 standards.
    •  Indeno(1,2,3-cd)pyrene: the oral cancer slope factor has been changed to 1E-1 1/(mg/kg/d) (from 1E-2, a data entry error), which makes the value consistent with that used in the derivation of the Method 1 standards.
    • Styrene: the chronic inhalation RfC was changed to 1 mg/m3 (from 2E-10, a data entry error) and the subchronic inhalation RfC was changed to 3 mg/m3 (from 2E-10). These values are consistent with IRIS.
    • Trichloroethylene: the oral cancer slope factor has been changed to 4.6E-2 1/(mg/kg/d) (from the rounded value of 5E-2), as listed in IRIS. The inhalation unit risk has been changed to 4.1E-6 1/(ug/m3) (from 5E-6), which makes the value consistent with that used in the derivation of the Method 1 standards.

Please note: the current set of shortforms does not include sf12osa and sf12osih (office worker, students & teachers exposure models). These worksheets are being revised and will be added to the Shortforms when they are complete.

MassDEP apologizes for any confusion or risk characterization errors that may been caused by these Shortform errors. The updated Shortforms may be used now for Method 3 risk characterizations. The previous Shortforms (i.e., the version posted by MassDEP prior to 11/13/23) may be used to support Permanent Solutions submitted to MassDEP prior to March 1, 2024, the effective date of the MCP amendments. 

Any questions regarding this information may be sent to [email protected].


BWSC.Information is a MassDEP service to Licensed Site Professionals, persons conducting response actions, the public and others seeking assistance in interpreting the Massachusetts Contingency Plan. The responses given are limited to the information provided in the question and as such, may not address the full range of issues related to the question. A BWSC.Information response is provided solely to assist the reader. It does not create any substantive or procedural rights, and is not enforceable by any party in any administrative or other proceeding with the Commonwealth.

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