EPA Extends Public Comment Period for Draft TSCA Risk Evaluation for 1 3-Butadiene

The U.S. Environmental Protection Agency (EPA) has extended the public comment period for its draft TSCA risk evaluation for 1,3-butadiene. Originally set to close on February 3, 2025, the deadline is now extended to March 5, 2025, to allow additional time for stakeholders to provide feedback.   

Key Findings of the Draft TSCA Risk Evaluation 

On December 2, 2024, the U.S. EPA released a draft risk evaluation for 1,3-butadiene (CAS No. 106-99-0) under the Toxic Substances Control Act (TSCA) for public comment and peer review by the Science Advisory Committee on Chemicals (SACC). EPA in its risk evaluation determined that 1,3-butadiene poses an unreasonable risk of injury to human health from inhalation exposure to workers and to the general population (including fenceline communities) which is associated with several health effects.   

1,3-Butadiene 

1,3-butadiene is a colorless, highly flammable gas with a mild odor similar to gasoline. It is used primarily in the manufacture of plastics, synthetic rubber (including tires), adhesives, fuels, lubricants, paints, and coatings. The chemical is commonly released into the air during its production and use, with minimal releases to land or water. Beyond industrial exposure, people may also encounter 1,3-butadiene in vehicle exhaust, tobacco smoke, and burning wood. 

Identified Health Risks  

Workers and Occupational Exposure:  

• Workers in manufacturing and processing facilities face significant health risks from inhaling 1,3-butadiene and maintenance and laboratory technicians are particularly vulnerable due to non-routine handling. Health effects include reduced birth weight, blood and immune system diseases, and leukemia. 

Fenceline Communities and the General Population:  

• For people living near industrial facilities long-term exposure from air emissions can lead to serious chronic health effects over time through inhalation. 

Minimal Consumer and Environmental Risk:  

• Consumer exposure is low since only trace amounts of 1,3-butadiene are found in products. The draft evaluation also concludes that there is no unreasonable environmental risk, as 1,3-butadiene does not have a significant impact on land or water. 

Uses of 1,3-Butadiene 

1,3-butadiene uses that pose a significant risk: 

• Manufacturing and processing in industries such as rubber, plastics, adhesives, fuels, and coatings. 

• Handling, repackaging, and disposal of 1,3-butadiene. 

• Recycling and laboratory use. 

Uses that pose low or no risk: 

• Consumer and industrial use in fuels 

• Automotive products 

• Lubricants 

• Packaging 

• Furniture 

• Toys  

• Distribution in commerce 

Public and Peer Review Comments 

EPA was previously accepting public comments for 60 days after the draft evaluation but has extended the comment period from February 3, 2025, to March 5, 2025. Public comments can be submitted to docket EPA-HQ-OPPT-2024-0425 on www.regulations.gov until the new deadline. 

A preparatory public meeting to discuss the scope of the evaluation scheduled for February 4 and the virtual SACC peer review meeting to review public comments and finalize recommendations was scheduled for February 25-28, 2025, but EPA is now rescheduling the February peer review meetings to review additional comments and will announce new dates soon.