The release of the Toxic Substances Control Act (TSCA) Section 5(a)(3)(C) determination for a new polymer, P-16-0510, represents a positive step in implementing the New Chemicals Program under the Frank R. Lautenberg Chemical Safety for the 21st Century Act. The new chemical is intended to be used as a deodorizer in a variety of products, including floor cleaners, cat litter, fabric freshener sprays and other consumer products. This column explains why this is a significant development.
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Since the TSCA’s 2016 revision, review of new chemicals under Section 5 has slowed dramatically. The law requires the U.S. Environmental Protection Agency (EPA) make one of three determinations at the conclusion of its review of new chemicals; however, the introduction of new terms and concepts has confounded the process. Among those concepts is what the EPA considers “reasonably foreseen” conditions of use of the new chemical.
Since mid-2016, the EPA’s interpretation has been such that most new chemicals, approximately 90%, have been targeted for regulation. This sharply contrasts to pre-Lautenberg numbers, where approximately 10% of new chemicals were targeted for regulation. In the document summarizing the EPA’s review of the new polymer, the agency states there are no known or reasonably foreseen conditions of use other than those intended by the submitter. This may not appear to be a controversial statement. Based on the EPA’s more recent interpretation of “conditions of use,” the agency seems to have construed what is reasonably foreseeable to be extraordinarily generous. It includes use patterns far beyond what the submitter intends and what is well beyond the EPA’s commitment, to base what is “reasonably foreseen” on information, knowledge, or experience, not on any conceivable condition of use.
The New Polymer
The EPA identifies the new chemical’s potential health hazard endpoints based on the acrylate/acrylamide category. Causes for concern for acrylamide and certain low molecular acrylamide analogs include mutagenicity, developmental toxicity, reproductive effects, neurotoxicity, and a “marginal potential” for oncogenicity. While this may appear alarming, the real question is how toxic the new chemical is, and are exposures expected to exceed a “safe” level? Risk, after all, is a function of hazard and exposure. The EPA considered the low-molecular weight (LMW) components of the polymer (i.e., the “worst case”) in its assessment and identified two analogs of the LMW components. The EPA also took into account the toxicity of acrylamide in its assessment. Based on the analogs, the EPA set a no observable adverse effect level of 250 mg/kg/day, which placed the substance in the low-to-moderate toxicity category.
The agency also identified ecotoxicity concerns. Using its predictive models, the EPA predicted toxicity levels for acute and chronic effects to aquatic species, and set concentrations of concern at levels that put the substance in the “moderate” category for environmental hazard.
The EPA applied exposure modeling to predict exposures to workers, the general population and consumers. Results indicated that predicted exposures were sufficiently below the EPA’s concern level to not present an unreasonable risk to workers, the general population or consumers. The EPA even found that at the “worst case” of 100% of the premanufacture notification (PMN) substance, exposures would be below the EPA’s concern level. The EPA also evaluated surface water concentrations and determined that the estimated maximum acute and chronic concentrations didn’t exceed the concern level.
Discussion
The EPA reviewed the new chemical’s likely and potential exposures to workers, the general population, consumers, and aquatic species, and did not identify any foreseeable conditions of use that would lead it to predict that unreasonable risk was likely. This approach is a welcome departure from previous new chemical decisions, where in nearly all cases, the EPA only made a “not likely” determination if it identified a low hazard for both health and ecological effects. Absent such a finding, the EPA appeared to believe there could be some conditions of use that could contribute exposures exceeding the EPA’s concern levels.
In the case of P-16-0510, the EPA applied the new TSCA as written. It identified a low-to-moderate health concern and a moderate eco concern, and took a reasonable approach grounded on the law to go beyond the mere consideration of potential hazard and to interpret the “reasonably foreseen” conditions of use and assess unreasonable risk as the new TSCA requires. The EPA’s measured approach indicates a maturation of its understanding of what’s needed to meet a not likely determination. The agency may wish to articulate its thinking on what is and isn’t “reasonably foreseeable” and what PMN submitters can do to help the EPA understand not only what is intended, but what might be “reasonably foreseen” for TSCA Section 5 purposes.
