EPA to regulate 1,3-butadiene in 11 industrial manufacturing settings

In this article:

• Why is 1,3-Butadiene hazardous in manufacturing?
• The EPA’s scientific review process
• List of all 11 use cases that present unreasonable health risks
• Next steps: regulatory rule development

The U.S. Environmental Protection Agency (EPA) recently announced it intends to regulate the use of 1,3-butadiene across 11 industrial settings.

The EPA released its final risk evaluation for 1,3-butadiene Dec. 31 under the Toxic Substances Control Act (TSCA) in compliance with a court ordered deadline. The EPA designated 1,3-butadiene as a high-priority chemical in December 2019.

As required by law under the TSCA, the EPA will now develop regulations to protect workers from the risks it identified.

Why is 1,3-Butadiene hazardous in manufacturing?

1,3-Butadiene (CASRN 106-99-0), is a colorless, flammable gas used to manufacture plastic and synthetic rubber polymers, which are used to make products including car tires, adhesives, sealants, paints, coatings, automotive care products, and lubricants.

Consumer products only contain tiny amounts of this chemical - less than 0.001% - which is safe for everyday use. But the EPA said unreasonable risks are found in industrial settings where workers may be exposed to much higher levels.

In industrial workplaces where 1,3-butadiene is manufactured or used to make products, high levels of exposure can cause health risks such as reduced birthweight pregnancies, anemia, leukemia, and bladder cancer. These risks are not seen when people use consumer products.

Scientific review analyzed 30 direct workplace exposure use cases

The review process for 1,3-butadiene took six years, with approximately 20,000 scientific studies considered during the review process.

EPA evaluated 30 conditions of use (COU) involving direct workplace exposure - where the highest potential exposures occur - following standard scientific practices to provide clear results about the chemical's specific risks.

The agency said it used input from the public and independent expert peer reviewers to complete its evaluation.

The EPA improved its evaluation by incorporating real-world data and refining some conservative assumptions from its first draft, improving accuracy and reliability to better reflect facility-specific conditions.

The agency also took into account additional feedback from peer reviewers recommending it add together the risks from bladder cancer and leukemia. This resulted in a higher overall cancer risk estimate used in the risk evaluation.

PPE can help reduce exposures, mitigate risks

EPA found potential unreasonable health risks for workers who inhale this chemical at their jobs in 11 specific industrial settings:

1. Manufacturing - domestic manufacturing
2. Manufacturing - importing
3. Processing as a reactant - intermediate in various industries such as adhesive manufacturing and synthetic rubber manufacturing
4. Processing as a reactant - monomer used in polymerization process in synthetic rubber, plastic material, and resin manufacturing
5. Processing - incorporation into formulation, mixture, or reaction product - monomers in plastic, resin, and synthetic rubber manufacturing
6. Processing - incorporation into formulation, mixture, or reaction product - plasticizer in asphalt paving, roofing, and coating materials manufacturing
7. Processing - incorporation into article - monomer in rubber product manufacturing
8. Processing - use-non-incorporative activities - fuel in petroleum refineries
9. Processing - repackaging in wholesale and retail trade involving synthetic rubber and petrochemical manufacturing
10. Processing - recycling
11. Disposal

For COUs with unreasonable risks to workers, these determinations do not reflect PPE already in use, including masks and respirators. However, PPE may reduce exposures and help mitigate risk.

The scientific review found there are no unreasonable risks for consumers or the general population, including people living near manufacturing facilities, nor are there risks to environmental receptors.

Next steps: regulatory rule development

The evaluation will help inform protections for American workers while allowing U.S. companies to continue making important products safely.

The agency will carefully consider health effects, exposure levels, how the chemical benefits society, and economic impacts, with extensive stakeholder engagement to ensure the resulting rules are both protective and practical.

Input from workers, companies, and the public will be crucial to make sure the final rules protect health while being protective of vulnerable populations, such as women who are pregnant or of childbearing age, and practical for businesses.

This next step, when finalized, will give companies clear rules to follow while providing workers with necessary protections they need to stay safe on the job.

The EPA said it will ensure the protections put in place are workable, taking additional action if new science emerges or conditions change.