EPA proposed to designate five chemicals as High-Priority Substances for risk evaluation under the nation's chemical safety law, the Toxic Substances Control Act (TSCA). If EPA finalizes these designations as proposed, the agency would immediately move forward with the risk evaluation process. This step is consistent with a commitment from the Administration to understand and address environmental and toxic exposures to ensure that every community has access to clean air and water, supports the Cancer Moonshot's mission to end cancer as we know it, and bolsters the Administration's efforts to make progress on delivering environmental justice and tackling plastic pollution. The five chemical substances EPA is proposing to designate as High-Priority Substances are: Vinyl Chloride (CASRN 75-01-4), Acetaldehyde (CASRN 75-07-0), Acrylonitrile (CASRN 107-13-1), Benzenamine (CASRN 62-53-3), and 4,4'-methylene bis(2-chloroaniline) (MBOCA) (CASRN 101-14-4).