MCP Changes - January 15, 1997

Dear Licensed Site Professionals and Interested Parties:

The purpose of this letter is to briefly discuss the status of DEP's new "VPH/EPH" approach and methodologies. As there appears to be some confusion on this issue, I urge you to carefully read and consider the information contained and cited in this correspondence.


In August, 1994, DEP published a document entitled "Interim Final Petroleum Report: Development of Health-Based Alternative to the Total Petroleum Hydrocarbon (TPH) Parameter". This report proposed a new scientific approach to characterize the risks posed by petroleum products released to the environment. The basis of this approach involves the assignment of toxicity factors (Reference Doses) to collective fractions of aliphatic and aromatic hydrocarbons that comprise petroleum products of interest.

In August, 1995, DEP published two draft analytical methods for the determination of Volatile Petroleum Hydrocarbons (VPH) and Extractable Petroleum Hydrocarbons (EPH). The development of such methodologies was necessary to produce data to apply the new toxicological approach.

In May, 1996, DEP disseminated a document entitled "Issues Paper: Implementation of VPH/EPH Approach". The purpose of this document was to identify and discuss key issues surrounding the regulatory implementation of the new approach, including the development of cleanup standards for soil and groundwater. Recommendations were offered in a number of areas, and public comment was solicited.

Finally, on November 1, 1996, DEP formally proposed a series of changes to the Massachusetts Contingency Plan (MCP), including a set of proposed "Method 1" cleanup standards for specific aliphatic and aromatic hydrocarbon fractions quantitated using the VPH and EPH analytical methods. Public hearings were held on November 25, 26 and December 2, 1996.

Finalizing VPH/EPH Approach in Regulation and Transitioning Issues

DEP hopes to finalize the VPH/EPH regulatory changes and analytical methods, with supporting guidance, in March of 1997. On the basis of comments received on the proposed Method 1 standards and new toxicological and technical information and data, DEP now believes it has adequate documentation to support recalculation of a number of the groundwater standards proposed in the November 1, 1996 public hearing draft, and will re-issue a second public hearing draft on January 17, 1997. The comment period for this second draft will run from January 17, 1997 through February 21, 1997. A public hearing will be held on February 7th at One Ashburton Place, 21st Floor, Boston at 9:30 a.m.

Another key issue to be discussed in the second draft, and for which additional public comment will be requested, is how the new VPH/EPH approach and standards will be incorporated and transitioned into the waste site cleanup process.

DEP believes the new methods represents a substantial advancement in the science of site assessment and risk characterization. Therefore, DEP views the use the new methods to characterize petroleum sites as the appropriate level of diligence commensurate with the Response Action Performance Standard (RAPS) specified at 310 CMR 40.0191. Nonetheless, we are sensitive to concerns about transitioning and the "retroactive application" of the VPH/EPH approach and methods to sites where an RAO has been submitted or where assessment and cleanup actions are nearing completion. Accordingly, DEP is seeking to find a reasonable balance between the need to adequately protect human health, public welfare, and the environment, and the need for certainty with respect to cleanup requirements by those conducting work at sites.

At this time, DEP intends to pursue this transitioning in the following manner:

  • After a specified "effective date", which will be identified in the final regulations, all submittals received by DEP will be expected to address the risk concerns and issues characterized by the VPH/EPH approach, within the context of RAPS. Some consideration may be given to a conditional "grandfathering" of sites that have reached a certain milestone prior to this effective date (e.g., RAO or Phase III Completion Statement).
  • While DEP will not as a general practice expect or require the application and use of the VPH/EPH approach to sites closed prior to the specified effective date, it reserves the right to do so in cases where compelling health or environmental concerns are evident (e.g., active drinking water well impacted by a release of gasoline).

I encourage you to provide DEP with comment on this important issue in your testimony or written comments on the January 17, 1997 public hearing draft.

Options for Assessing Petroleum Contamination Pending Finalization of VPH/EPH Regulatory Proposals

There has been some confusion regarding the application and use of the evolving VPH/EPH approach and methods, and how they may and/or should be used at the present time. Please be advised that pending the finalization of all VPH/EPH regulatory changes and policy documents, LSPs have the following options and responsibilities when characterizing risks at petroleum contaminated sites:

  1. At sites where releases of fuel oil and other mid to heavy distillates have occurred, continued use of a "TPH" test method, and comparison to the current MCP Method 1 standard, is acceptable. In addition to TPH, the need to ascertain the presence of other Method 1 standards, such as PAHs, should be determined on a site-specific basis. Direct comparison of toxicity weighted or Equivalent TPH data to the current MCP Method 1 TPH standards, however, is not appropriate (see discussion of "Toxicity Weighted TPH Values" below).
  2. At sites where releases of gasoline and other light distillates have occurred, risks may be characterized by use of traditional indicator compounds, such as benzene, toluene, ethylbenzene, xylenes, (BTEX) and MTBE, unless site conditions indicate the presence of direct exposure pathways of concern (e.g., drinking water wells). In such cases, use of the VPH approach should be considered, since consideration of only BTEX and MTBE may significantly underestimate risks posed by the numerous other hydrocarbon constituents of these light distillates.
  3. As indicated in the November 1, 1996 public comment draft, pursuant to the provisions of 310 CMR 40.0982(7), the Method 1 cleanup standards proposed in the November 1, 1996 public hearing draft, as well as those proposed in the January 17, 1997 draft, may be used immediately, under a Method 2 risk characterization process.
  4. Finally, the VPH/EPH approach may be used as part of a Method 3 risk characterization at any site.

Toxicity Weighted TPH Values

Perhaps the most confusing and problematic issue that has arisen since the issuance of the VPH/EPH proposals is the use of toxicity weighted or "Equivalent" TPH values.

In the draft VPH and EPH analytical methodologies, a proposal was made to weight aliphatic and aromatic fractions on the basis of their human health toxicities (Reference Doses), and have laboratory data reported as a toxicologically weighted or Equivalent TPH value. Reference to a toxicity weighted TPH method was also made in an amendment to the MCP in 1995, to provide a regulatory place holder for the new approach, pending finalization of the methods and standards.

It has since become apparent, however, that human health risks may not be the most sensitive exposure pathway at many sites, nor the controlling factor in many of the Method 1 cleanup standards. Rather, leaching, ecological, and/or staining and odor (public welfare) conditions are oftentimes of more serious concern. This finding was communicated and discussed in the May 1996 Issues Paper. Please note that the final analytical methods will not contain toxicity weighted adjustment factors, and that all proposed and final MCP cleanup standards must be compared to actual (unadjusted) site data.

It has come to DEP's attention that some LSPs have been comparing toxicity-weighted VPH/EPH data to current Method 1 TPH standards, and closing out sites on this basis. While this action will be protective of human health concerns, it will not necessarily be protective of all pathways of interest specified in the MCP. Of most concern are ecological impacts, and the presence of petroleum odors, which could constitute a significant risk to public welfare. This is particularly problematic at sites where an A-2 or B-1 Response Action Outcome (RAO) is filed without an Activity and Use Limitation, as the soil at such sites may be disturbed and/or reused at other locations in the future as "residential quality" soils.

LSPs, therefore, should consider reviewing any previously filed A-2 or B-1 RAOs that were based on the comparison of toxicity-weighted data to current Method 1 TPH standards, if leaching, ecological or odor concerns were not also independently addressed. If necessary, LSPs may want to consider filing additional supporting information and data to demonstrate that all exposure pathways and concerns have been adequately addressed.


DEP is looking forward to the completion of this multi-year effort to advance the science and regulation of petroleum contaminated sites. We are pleased to note that, since the issuance of our conceptual proposal in 1994, a number of states, Canadian Provinces, EPA regional offices, and national workgroups have recommended, adopted, or are actively considering, identical or similar proposals.

I would like to thank you for your interest, patience, and comments in this regard, and encourage your continued participation in the finalization and implementation of this effort. Please note that DEP is planning a series of educational seminars once all details and standards have been finalized, to provide the LSP community with complete information and training on the new approach and methodologies.

If you have any further questions, please contact John Fitzgerald at (617-932-7702 or email In order to prevent any additional confusion in this regard, please direct all of your questions on this topic to John.

Very truly yours,

James C. Colman
Assistant Commissioner
Bureau of Waste Site Cleanup