Common phthalate plasticizers pose health risks, EPA finds

More than a dozen uses of two common phthalates—diethylhexyl phthalate (DEHP) and dibutyl phthalate (DBP)—pose health risks to workers from inhalation exposure, the US Environmental Protection Agency concludes in draft risk assessments released June 4. But the EPA did not assume in its evaluation that workers use personal protective equipment (PPE), such as respirators. Use of PPE may reduce exposures and mitigate risk, the agency says. These are the first draft risk assessments published by the EPA in the second administration of Donald J. Trump.

The EPA evaluated uses of only the phthalates under the jurisdiction of the Toxic Substances Control Act (TSCA), including manufacturing of plastics, resins, synthetic rubber, and organic chemicals. The agency did not consider use in cosmetics, medical devices, and food additives, which are regulated by the US Food and Drug Administration.

DEHP and DBP are primarily used as plasticizers to make polyvinyl chloride (PVC) flexible. The EPA found no health risks to consumers from DEHP in items such as lawn and garden products, adhesives, sealants, batteries, paints and coatings, construction materials, electronics, textiles, and furnishings. The agency did, however, find health risks to consumers associated with dermal exposure to DBP in automotive products, paints, coatings, sealants, adhesives, and cleaning and furnishing-care products.

Concerns about the developmental and reproductive toxicity of DEHP and DBP—particularly adverse effects on the developing male reproductive system—led the EPA to include the two chemicals in a cumulative risk analysis with other phthalates that also cause such effects. Those other phthalates are butyl benzyl phthalate (BBP), dicyclohexyl phthalate (DCHP), diisobutyl phthalate (DIBP), and diisononyl phthalate (DINP).

On June 4, along with the draft risk assessments for DEHP and DBP, the EPA released an addendum to a document that describes how it characterizes cumulative risk specifically for phthalates that affect the male reproductive system.

The addendum provides a new option for cumulative risk characterization and clarifies a previous one that the EPA outlined in January. The agency plans to get input on both options from its Science Advisory Committee on Chemicals during a meeting Aug. 4–8. The committee will also peer-review all documents released so far that are related to risk evaluations of DEHP and DBP, as well as DCHP.

A draft risk evaluation for DCHP the EPA released in December found concerns for workers associated with 9 of 24 uses evaluated under TSCA. It did not find any uses of DCHP under TSCA that raise health concerns for consumers.

The agency plans to release draft evaluations for BBP and DIBP in July.

The EPA set off the risk evaluation in December 2019, when it designated DEHP, DBP, DCHP, BBP, and DIBP high-priority substances. Under TSCA, the agency is required to complete risk evaluations within 3 years of the initiation date, although a 6-month extension is possible.

EPA sued over missed deadlines

A coalition of advocacy groups sued the EPA in September 2023 for failing to meet the deadlines for those 5 phthalates and 15 other chemicals that the EPA designated high priority in December 2019. Under a consent decree, the EPA agreed to enforceable deadlines to complete the evaluations. The agency is now rolling out those evaluations and expects to complete them by Dec. 31, 2026.

In December 2023, the American Chemistry Council (ACC), an industry trade association, filed a similar lawsuit against the EPA for failing to meet its deadlines to evaluate diisodecyl phthalate (DIDP) and DINP.

Chemical manufacturers asked the agency to assess the human health risks of DIDP and DINP in 2019. The industry is promoting the two phthalates as safer alternatives to DEHP for use as plasticizers in making PVC.

In early January, during the final days of the Biden administration, the EPA finalized risk evaluations for DIDP and DINP. The agency found health risks to workers not wearing PPE for 6 of 49 uses of DIDP and 4 of 47 uses of DINP. It did not find any risks to consumers.

The ACC’s High Phthalates Panel welcomed those evaluations at the time, saying that the EPA’s findings reconfirmed manufacturers’ full confidence in the safety of DIDP and DINP.

The panel declined to comment on EPA’s draft evaluations for DEHP and DBP. A spokesperson notes that the panel promotes the benefits of the long-chain phthalates DIDP and DINP, not low-molecular-weight phthalates like DEHP and DBP.

Environmental and public health groups also declined to comment on the evaluations. Such groups are typically more concerned about phthalates in uses regulated by the FDA than those regulated by the EPA under TSCA.

In December, a coalition of public interest advocacy groups, represented by Earthjustice, sued the FDA to push the agency to reevaluate phthalates in food packaging. The agency has not updated its safety assessments for phthalates in food packaging in at least 40 years, the groups claim.