The Environmental Protection Agency has taken a significant step towards improving public health and environmental safety by proposing to designate five chemicals as High-Priority Substances for risk evaluation under the Toxic Substances Control Act. This move, announced on July 24, 2024, is part of the Biden-Harris Administration's broader efforts to address environmental justice concerns and support the Cancer Moonshot initiative. The proposal aims to evaluate the safety of these chemicals, which are all linked to cancer and used in plastic production, potentially leading to crucial public health and environmental protections across the United States.
The five chemicals proposed for evaluation are vinyl chloride, acetaldehyde, acrylonitrile, benzenamine, and 4,4'-methylene bis(2-chloroaniline). These substances were selected from the 2014 TSCA Work Plan, a list of chemicals identified by the EPA for further assessment based on their hazards and potential for exposure. The selection process considered various factors, including the chemicals' conditions of use, production volume, impacts on vulnerable populations, and potential hazards and exposures. The EPA also took into account specific criteria such as bioaccumulation, environmental persistence, and proximity to significant drinking water sources.
Vinyl chloride, one of the chemicals under scrutiny, gained particular attention following its involvement in the Norfolk Southern train derailment in East Palestine, Ohio. Primarily used in the manufacturing of plastic materials like polyvinyl chloride, vinyl chloride is a known human carcinogen that can cause liver, brain, and lung cancer in exposed workers. The other chemicals on the list - acetaldehyde, acrylonitrile, benzenamine, and MBOCA - are also associated with various cancers and other health risks, ranging from respiratory irritation to genetic damage and reproductive effects.
The prioritization process is the first step in the EPA's authority to regulate existing chemicals currently on the market and in use. If these designations are finalized, the agency will initiate risk evaluations for these chemicals to determine whether they present an unreasonable risk to human health or the environment under their conditions of use. This process must be completed within 3-3.5 years. Should the EPA determine that a chemical poses an unreasonable risk, it will begin the risk management process to eliminate these dangers.
Over the past year, the EPA has made significant improvements to its prioritization process. The agency has invested in advanced software to review more information earlier in the prioritization stage and has implemented improvements to its systematic review approaches as recommended by the Scientific Advisory Committee on Chemicals. These enhancements include incorporating additional data sources, clarifying terminology, and presenting interactive literature inventory trees and evidence maps to better depict relevant information sources.
As a result of these improvements, the EPA now has a more comprehensive understanding of how these chemicals behave in the environment and their potential hazards and exposures at this proposed designation stage compared to the previous prioritization cycle in 2019. This progress allows the agency to make considerably more information available to the public a year earlier than before. The public will have access to the studies and information EPA considered in its screening review for proposed designation and can submit additional information for consideration via public comment.
The EPA's proposal to evaluate these five chemicals represents a significant step towards addressing environmental and toxic exposures, supporting cancer prevention efforts, and advancing environmental justice. By focusing on these substances, many of which are used in plastic production, the agency is also contributing to efforts to tackle plastic pollution. As the process moves forward, it has the potential to lead to improved regulations and safer practices in chemical use and production, ultimately benefiting public health and the environment across the United States.
