U.S. EPA issues draft risk evaluation for 1,3-butadiene exposure

The U.S. Environmental Protection Agency (EPA) has issued a draft risk evaluation for 1,3-butadiene under the Toxic Substances Control Act (TSCA). The evaluation, now open for public comment and peer review, highlights significant health risks associated with inhalation exposure to 1,3-butadiene, primarily affecting workers and fenceline communities near industrial facilities. The findings mark a critical step in addressing chemical safety and informing potential regulatory actions.

1,3-butadiene, a colourless and highly flammable gas with a mild gasoline-like odour, is widely used in manufacturing processes, particularly in producing synthetic rubber, plastics, adhesives, and resins. It is also a by-product of petroleum refining and can be released into the air during industrial operations. According to the EPA’s draft evaluation, prolonged inhalation exposure to 1,3-butadiene is linked to severe health outcomes, including:

• Reduced birthweight in pregnancies.
• Blood and immune system disorders.
• Increased risk of leukaemia.

Workers are identified as the most at-risk group due to direct exposure during the manufacturing, processing, or maintenance of industrial equipment. Non-routine activities, such as laboratory technician maintenance, also significantly contribute to inhalation risks. Fenceline communities—residents living near industrial facilities—are similarly affected by emissions released into the surrounding air.

The draft evaluation preliminarily concluded that consumer exposure to 1,3-butadiene is minimal because it exists only in trace amounts in consumer products like adhesives, paints, and automotive care items. Furthermore, no unreasonable environmental risks were identified, as the compound does not significantly impact land or water systems under current conditions of use.

Industrial applications

1,3-butadiene plays a critical role in the production of synthetic rubber and plastics, which are essential components of everyday products, including:

• Automotive parts: Seals, hoses, and gaskets.
• Adhesives and coatings: Used in construction and packaging.
• Fuel additives: Indirectly used in refining and chemical processes.
• Polymer manufacturing: A building block for resins and synthetic materials.

Next steps for public and peer review

The EPA has initiated a 60-day public comment period to gather feedback on the draft evaluation. The Science Advisory Committee on Chemicals (SACC) will conduct a peer review during a virtual public meeting scheduled for February 25–28, 2025, with a preparatory session on February 4, 2025. Registration details for these meetings will be available on the SACC website in early 2025.

Comments and questions submitted during this period will play a pivotal role in refining the final risk evaluation and determining appropriate regulatory or mitigation actions to protect public health.

Stakeholders, including industry representatives, scientists, and the general public, are encouraged to participate in the review process by submitting comments via the Federal Register at EPA-HQ-OPPT-2024-0425. Feedback will inform the EPA’s final evaluation and subsequent safety measures to mitigate risks.

A crucial step toward chemical safety

The draft evaluation is part of the EPA’s ongoing commitment to regulating high-priority chemicals under the amended TSCA framework. Addressing the risks posed by 1,3-butadiene is a step toward ensuring industrial safety, protecting vulnerable populations, and promoting environmental health.

For more information, visit the EPA’s website or contact Brooke Porter at [email protected] or Alie Muneer at [email protected] for details regarding the peer review process.