EPA Releases Draft Risk Evaluations for Phthalates and Related Chemicals

On January 6, 2025, the U.S Environmental Protection Agency (EPA) released a draft risk evaluation for dicyclohexyl phthalate (DCHP) under the Toxic Substances Control Act (TSCA) for public comment. Alongside this, EPA published technical support documents and a cumulative risk analysis for several phthalates. This update focuses on the potential health risks of exposure to DCHP, particularly for workers, and its cumulative effects when combined with other phthalates. Public comments will be accepted for 60 days after publication. 

Draft Risk Evaluation for DCHP 

DCHP is widely used as a plasticizer and stabilizer in products such as polyvinyl chloride (PVC), adhesives, sealants, paints, and coatings.  

Key Findings:

• Unreasonable Risks to Workers: EPA’s preliminary findings indicate that DCHP poses unreasonable risks to human health, especially to workers exposed through inhalation. Potential health effects include harm to the developing male reproductive system. 

• Nine Key Conditions of Use Contributing to Risk: Manufacturing, industrial processing, and commercial applications in adhesives, paints, coatings, and printing inks. 

• No Environmental Risk: On evaluation it was determined that DCHP does not pose unreasonable risk to the environment or the general population. 

Exposure Pathways: 

• Workplace Exposure: Workers may be exposed through manufacturing and product use. 

• Environmental Exposure: DCHP may be released into water, where it settles in sediment. If released into air, it can adhere to dust particles, which may lead to inhalation or ingestion indoors over time. 

Excluded Uses:  

• Food contact materials were not assessed because they are exempt under TSCA. 

Cumulative Risk Analysis for other Phthalates 

EPA also conducted a cumulative risk analysis for six other phthalates: DCHP (CAS no. 84-61-7), benzyl butyl phthalate (BBP) (CAS no. 85-68-7), dibutyl phthalate (DBP) (CAS no. 84-74-2), di(2-ethylhexyl) phthalate (DEHP) (CAS no. 117-81-7), diisobutyl phthalate (DIBP) (CAS no. 84-69-5), and di-isononyl phthalate (DINP) (CAS no. 28553-12-0). This approach evaluates the combined health effects of these chemicals, in the similar manner as other American institutes and surveys have done before (NHANES, NASEM, CPSC) this approach evaluates the combined health effects of these chemicals, , leading to simultaneous exposures. 

Phthalate Syndrome & Relative Potency Factor (RPF) Approach

Animal studies have shown that prenatal exposure to these phthalates can cause adverse developmental effects, collectively known as phthalate syndrome,  including: 

•  Reduced fetal testicular testosterone 

• Male reproductive tract malformations  

• Reduced fertility 

EPA has also used the RPF approach to evaluate cumulative risks, focusing on the shared hazard of reduced fetal testicular testosterone, which is more sensitive than assessing individual chemicals separately. 

Technical support document for DIBP, DBP, DEHP and BBP

EPA has released key technical documents to support the cumulative risk analysis and future phthalate evaluations: 

• Physical chemistry and environmental fate and transport technical support documents to provide details on the properties and environmental behavior of phthalates. 

• Human Health (Non-Cancer) Hazards & Environmental Hazards to establish health risk values for exposure assessment and to identify the potential risks to the environment and safe exposure limits. 

Key Conditions of Use for DCHP 

EPA categorized DCHP’s conditions of use into two groups: 

Conditions Contributing to Unreasonable Risk:

• Manufacturing: Domestic production. 

• Processing: Used in adhesives, paints, coatings, and printing inks. 

• Industrial Uses: Includes finishing agents in cellulose film production. 

• Commercial Uses: Found in screen printing inks and coatings. 

Conditions Not Contributing to Unreasonable Risk: 

• Manufacturing: Importing. 

• Processing: Recycling and repackaging. 

• Distribution: In commerce or as part of low exposure products like adhesives and building materials. 

• Consumer Uses: Adhesives, coatings, and general articles with minimal direct exposure risks. 

What’s next? 

EPA has opened a 60-day public comment period for the DCHP draft risk evaluation (Docket: EPA-HQ-OPPT-2018-0504) on regulations.gov. Preliminary dockets for BBP, DBP, DEHP, and DIBP are open, with formal 60-day comment periods starting upon release of the draft evaluations. 

Phthalate Dockets: 

DIBP: EPA-HQ-OPPT-2018-0434 

DBP: EPA-HQ-OPPT-2018-0503 

DEHP: EPA-HQ-OPPT-2018-0433 

BBP: EPA-HQ-OPPT-2018-0501