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Chemical Categories Report

Prior to 1987, nearly 20% of PMNs submitted underwent a detailed review ("standard review") by EPA, a highly resource-intensive effort that lasts most of the mandated 90-day PMN review period. In 1987, after several years of experience in the review of PMNs, EPA's Office of Toxic Substances (now the Office of Pollution Prevention and Toxics) had enough accumulated experience to group PMN chemicals with shared chemical and toxicological properties into categories, enabling both PMN submitters and EPA reviewers to benefit from the accumulated data and past decisional precedents allowing reviews to be facilitated. The first category was "acrylates and methacrylates."

Currently, there are a total of 55 categories. As expected, establishing these categories has streamlined the process for Agency review of new chemical substances. Based on current information, the Agency takes action to control potential risks to health or the environment on approximately 10% of the PMNs submitted. Only 2-3% of the total number of PMNs submitted (20-30% of the above 10%) now undergo a standard review, while the remaining 7-8% are identified as members of the New Chemicals Program chemical categories.

Candidate categories for the New Chemicals review process are proposed by New Chemicals Program staff, based on experience reviewing PMNs on similar substances. At proposal, the database supporting the category is scrutinized for quality and for general applicability to other potential members of the category. Based on this analysis, a category statement is prepared describing the molecular structure a new chemical must have to be included in the category, boundary conditions such as molecular weight, equivalent weight, the log of the octanol/water partition coefficient (log P), or water solubility, that would determine inclusion in (or exclusion from) a category, and standard hazard and fate tests to address concerns for the category.

As it gained experience with reviews of chemicals in categories, EPA moved decision-making authority for the category chemicals to a point much earlier in the 90-day PMN review period. This point is the Focus Meeting, where exposure and hazard information about a PMN substance is first brought together for a risk management decision. When a new substance is identified as being a member of a category, the chemical is evaluated in the context of the potential health or environmental concerns associated with that category. If, based on an assessment of the potential exposures and releases associated with the new chemical, EPA concludes that the new substance may pose an unreasonable risk to human health or the environment, testing and restrictions may be required. The New Chemicals Program draws upon the expertise within the Office of Pollution Prevention and Toxics to determine the effectiveness of protective equipment, consistency with existing chemical regulatory activity in the Agency, affordability of certain testing, etc., in formulating the appropriate regulatory response for each new chemical submitted within a category. Therefore, although the categories save program resources devoted to the review of the hazards associated with individual PMN substances, considerable effort is still required to develop risk management options, communicate the Agency's decisions to the PMN submitters, and, if necessary, negotiate consent agreements aimed at controlling those potential risks.

It is important to note that substances which fall into the categories are not necessarily the chemical substances of greatest concern to the Agency. That is, the categories may not be made up of the most hazardous chemicals, but rather they include chemicals for which sufficient history has been accumulated so that hazard concerns and testing recommendations vary little from chemical to chemical within the category. Of course, the categories are not intended to be a comprehensive list of all substances that may be subject to further action in the New Chemicals Program.

 

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