On October 5, 2012, the U.S. Environmental Protection Agency (EPA) promulgated a final significant new use rule (SNUR) for potassium titanium oxide, which was previously the subject of a consent order under Section 5(e) of the Toxic Substances Control Act (TSCA). EPA states that, based on test data on the premanufacture notice (PMN) substance and structure activity relationship analysis of test data on analogous respirable, poorly soluble particulates (subcategory titanium dioxide), EPA “identified concerns for lung toxicity and fibrosis in workers exposed to the PMN substance by the inhalation route.” EPA issued the consent order based on a finding that the substance may present an unreasonable risk of injury to human health. The conditions required by the consent order include “[n]o manufacture of the PMN substance with a particle size less than 100 nanometers.” The final SNUR designates as a significant new use the absence of the protective measures required by the consent order. According to the SNUR, EPA determined that a 90-day inhalation toxicity test with special attention to histopathology of the lung tissues and to various parameters of the broncoalveolar lavage fluid would help characterize the human health effects of the PMN substance. The SNUR will be effective on December 4, 2012. Written adverse or critical comments, or notice of intent to submit adverse or critical comments, are due November 5, 2012.
