Summary:
The Environmental Protection Agency (EPA or Agency) is announcing the availability of the final risk evaluation under the Toxic Substances Control Act (TSCA) for 1,3-butadiene (CASRN 106-99-0). The purpose of risk evaluations under TSCA is to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment under the conditions of use, including unreasonable risk to potentially exposed or susceptible subpopulations identified as relevant to the risk evaluation by EPA, and without consideration of costs or non-risk factors. EPA used the best available science to prepare this final risk evaluation and determined, based on the weight of scientific evidence, that 1,3-butadiene poses unreasonable risk to human health driven by specific conditions of use. EPA will now initiate risk management actions to address the unreasonable risk.