Industry’s phthalates gamble is paying off

A decade ago, chemical makers saw the writing on the wall. Concerns about the toxicity of phthalates—inexpensive, versatile chemicals that are used to make polyvinyl chloride (PVC) flexible—were prompting regulators to restrict their use, particularly in products for children. Retailers stopped selling items containing the most problematic phthalates, and manufacturers began seeking replacements.

Today, companies are expanding capacity for nonphthalate PVC plasticizers. But they haven’t given up on phthalates. In the US, chemical manufacturers are betting on two—diisodecyl phthalate (DIDP) and diisononyl phthalate (DINP)—as safer alternatives to di(2-ethylhexyl) phthalate (DEHP), the gold standard for PVC plasticizer performance.

So far, they are winning that bet. In 2019, manufacturers asked the US Environmental Protection Agency to evaluate the human health risks of DIDP and DINP under the Toxic Substances Control Act (TSCA). Companies typically don’t want regulatory scrutiny of their products, but in this case industry scientists were convinced that the EPA would find that the chemicals do not pose an unreasonable risk to human health or the environment.

For the most part, that’s what the EPA concluded in its final risk evaluations for DIDP and DINP. The agency released the findings Jan. 3 for DIDP and Jan. 14 for DINP as part of a last-minute push to finalize risk evaluations and rules to manage chemical risks under TSCA before the second administration of Donald J. Trump begins on Jan. 20.

The EPA concluded that 6 out of 49 uses of DIDP and 4 out of 47 uses of DINP pose an unreasonable risk to unprotected workers. Manufacturers are breathing a sigh of relief, as those uses represent only about 1% and 3% of US production volume of DIDP and DINP, respectively. The agency did not find risks associated with the use of DIDP or DINP in PVC or any risks to consumers. The risks it found to workers were from industrial spraying of adhesives, sealants, paints, and coatings containing the phthalates, particularly to female workers of reproductive age not wearing protective equipment.

The EPA didn’t evaluate the risks of DIDP or DINP in food packaging, cosmetics, or medical equipment because those products are regulated by the US Food and Drug Administration and aren’t under the jurisdiction of TSCA or the EPA.

The American Chemistry Council (ACC), which represents chemical manufacturers, welcomes the findings.

The evaluations reconfirm manufacturers’ full confidence in the safety of DIDP and DINP as currently used, the ACC’s High Phthalates Panel says. “Uses such as PVC film and sheet, fabrics, textiles, and apparel, building and construction materials (wire or wiring systems, joint treatment, fireproof insulation), non-spray applications of paints and coatings, non-spray applications of adhesives and sealants, and recycling, to name a few, pose no unreasonable risk.”

But the ACC questions why the EPA based its conclusions on conditions that are not likely in the real world, where automation and personal protective equipment are routinely used. The EPA’s assumption of “workers spraying high concentration products at high pressure for 8 hours a day without protective equipment” is unlikely in industrial and commercial settings, the group says.

In all its chemical risk evaluations under TSCA, the EPA assumes that workers are not wearing protective equipment. One of the ways the agency is likely to mitigate the risks of DIDP and DINP is by requiring workers to wear protective gear.

The High Phthalates Panel has claimed for years that DIDP and DINP do not pose a risk to human health at typical exposure levels. The panel criticized the Consumer Product Safety Commission (CPSC) in 2017 for restricting the use of DINP in toys and childcare articles. The CPSC’s restrictions on DINP is what prompted chemical manufacturers 2 years later to ask the EPA to evaluate the chemical under TSCA.

The EPA’s analysis found most uses of DIDP and DINP under TSCA safe as exposure levels are below those that cause developmental toxicity and liver damage.

DINP is more toxic than DIDP because it causes effects at lower levels in rodents, the EPA says. The agency also found evidence suggesting that DINP, but not DIDP, can disrupt development of the male reproductive system, causing a condition known as phthalate syndrome. But those effects occur at much higher levels than those people are exposed to in uses regulated under TSCA, the EPA says.

Five other phthalates that the EPA is evaluating under TSCA also cause phthalate syndrome, it says. They are DEHP, butyl benzyl phthalate (BBP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), and dicyclohexyl phthalate (DCHP).

Because DINP and those five phthalates cause the same health effects and because people are exposed to many of them at the same time, the EPA conducted a cumulative risk analysis of all six, much like other agencies—including the CPSC, Health Canada, and the European Chemicals Agency—have done.

The EPA released a draft of the cumulative analysis Jan. 6.

Also on Jan. 6, the EPA released a draft risk evaluation for DCHP. The agency considered the cumulative analysis in the DCHP risk evaluation and says that it plans to do the same for the other phthalates it is currently evaluating. It expects to complete separate risk evaluations for DCHP and the other four by the end of the year.

When the EPA finds unreasonable risks associated with a chemical that it evaluates under TSCA, it must publish within 2 years a final rule to manage those risks. The agency will now start that process for DIDP and DINP. It plans to propose rules within 1 year to protect workers from the risks it found.

Public interest groups say the rules won’t protect consumers since their biggest source of exposure to phthalates is food. In 2016, a coalition of advocacy groups petitioned the FDA to ban 28 phthalates in food packaging. The agency denied the petition in 2022, saying the petitioners did not provide the scientific evidence to demonstrate that phthalates are unsafe for food contact uses. At the same time, the agency granted a petition from the Flexible Vinyl Alliance, a plastics trade group, to prohibit food contact use of 25 phthalates that it says industry no longer uses.

Health advocates aren’t giving up. Last month the Center for Food Safety and other groups, represented by Earthjustice, sued the FDA to force it to take another look at phthalates authorized for use in food packaging.

“The harms from phthalates leaching into our foods are serious, and most importantly, they are preventable,” Peter Lurie, president of the Center for Science in the Public Interest, says in a statement. “The FDA has failed to consider decades of accumulating scientific evidence in the record that the continued use of phthalates is unsafe, and the agency also failed to fully consider the cumulative effects of exposure to multiple phthalates, as the law requires.”

As part of a larger effort to review chemicals in the food supply, the FDA is reevaluating the safety of nine phthalates allowed in materials that come into contact with food. The agency plans to update the safety assessment for authorized food contact uses of phthalates later this year.