Chemical Categories Used to Review New Chemicals under TSCA
EPA groups Premanufacture Notice (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. Currently, there are a total of 56 categories. Establishing these categories has streamlined the process for Agency review of new chemical substances.
EPA will periodically update the Chemical Categories Document. The most recent updated version is the August 2010 version. This version is available below as a PDF.
How does EPA define a chemical category?
Candidate categories are proposed by EPA's New Chemicals Program reviewers, 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.
How does EPA evaluate chemicals included in a category?
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. It is important to note that substances which fall into the categories are not necessarily the chemical substances of greatest concern to EPA. 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.
How does EPA take risk management actions for chemicals in a 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.
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 tailored risk management options, communicate the Agency's decisions to the PMN submitters, and, if necessary, issue consent orders aimed at controlling those potential risks.