Cancer Listing for Plastics Chemical Unlikely to Burden Companies

By Pat Rizzuto

A federal science panel soon will decide whether a chemical made or imported by BASF, DuPont, Campine NV, and Lanxess Corp. to make flame retardants, batteries, and plastics should be classified as a potential human carcinogen.

The classification is not expected to immediately impose new labeling or hazard communications, industry spokespeople said.

The science panel’s backing would be one more step toward an official classification of antimony trioxide in the U.S., which eventually could trigger tighter regulations in California, other U.S. states, and in other countries, an industry official with Belgium-based Campine who opposes the classification told Bloomberg Environment. Despite his opposition, the panel’s vote and even the potential classification won’t immediately harm business, he said.

BASF, DuPont, and Lanxess are among the chemical companies that have made antimony trioxide or imported it into both the U.S. and the European Union for a variety of applications, according to information the companies provided the European Chemicals Agency and the U.S. Environmental Protection Agency.

Five physicians described the federal scientific analysis underlying the proposed classification as “comprehensive and well-written.” Antimony trioxide, however, can raise possible health concerns beyond cancer, they said in comments submitted for the science panel’s review.

Antimony trioxide is used as a synergist that helps make flame retardants more effective in plastics, paints, specialty textiles, and other products, the International Antimony Association said.

Worker Exposures

Antimony trioxide also is used to make polyethylene terephthalate (PET), plastics that are used for bottled water containers and other beverages. While it’s used in the production process, the compound isn’t found in final consumer products, reducing the potential for public exposure.

Exposure also can occur during lead acid battery production, the National Toxicology Program said in a draft analysis of the chemical. Antimony is among the materials that are added to lead to provide strength and to improve electrical properties.

Workers are the population that potentially has the greatest exposure, according to the program’s analysis.

A panel of scientists is scheduled to peer review the draft analysis Jan. 24 and vote on the toxicology program’s draft classification of antimony trioxide as a “reasonably anticipated” human carcinogen. The proposed listing was based on test animal evidence backed by cellular studies of biological activity.

The peer review panel’s recommendation is one step toward what could be antimony trioxide’s listing in the federal Report on Carcinogens, which lists known and reasonably anticipated carcinogens. The steps, detailed by the toxicology program, conclude with a final decision, which is made by the secretary of the Department of Health and Human Services.

Science Dispute

Michael Greenberg, a physician and public health professors at Drexel University College of Medicine in Philadelphia, along with four colleagues praised many aspects of the toxicology program’s analysis.

Their comments also listed additional ways workers could be exposed and health concerns beyond cancer, such as spontaneous abortions among pregnant workers, that some studies have associated with antimony trioxide.

But Wim De Vos, chief executive officer of Campine, a Belgian company that’s been in the antimony business for 100 years, told Bloomberg Environment the science about how antimony trioxide affects human health doesn’t warrant the proposed cancer classification.

While very high doses of antimony trioxide have caused lung cancer in laboratory animals, “comparable evidence has not been observed in workers,” he said. “Modern workplaces do not have high occupational presence of antimony trioxide in workplace air and have not observed a particularly increased incidence of lung cancer in their workforce, compared to the normal population.”

Campine and the International Antimony Association detailed their objections to the National Toxicology Program’s interpretation of scientific studies involving antimony trioxide and offered their evaluations in comments submitted to the peer review panel.

“There is no reason to conclude that antimony trioxide would be a potential human carcinogen,” Campine wrote.

Business Impacts

The inclusion of antimony trioxide in the Report on Carcinogens (RoC), “is still under discussion, but could indeed yield a number of consequences, said De Vos, who is also chairman of the International Antimony Association’s board.

“Substances listed on RoC are more likely picked up in regulations at the U.S. federal or state level, and can also inspire other territories beyond the U.S. But it is important to note that the RoC is not regulation and does as such not trigger any changes in the value chain which are determined by regulations only,” he said.

There are several reasons the classification won’t be an immediate effect, according to De Vos.

First, a World Health Organization agency classified antimony trioxide as probably carcinogenic to humans in 1989. “As antimony trioxide has been classified as a potential carcinogen for decades now, exposure controls are probably in place already,” De Vos said. The listing, however, could prompt companies to reinforce the safe use conditions they employ, he said.

DuPont’s comments echoed Campine’s. “We do not expect the proposed classification of antimony trioxide will significantly impact our business operations,” said company spokesman Dan Turner.

Protecting workers’ safety and health is the company’s top priority, Turner said. “DuPont already uses internal safety standards, guidelines, and personal protective equipment to protect workers, he said. “If the agency reclassifies the substance, we will review our standards and protective equipment to ensure worker safety.”

A second reason the RoC listing would be unlikely to have an immediate business impact involves the market, De Vos said. The price of the metal spiked in 2011 after the closure of antimony mines in China, according to the U.S. Geological Survey.

Companies that could use antimony trioxide alternatives already switched to them, according to De Vos. The companies that use the metalloid now, “would hence not consider using less antimony trioxide or changing to another substance, as their priority is to guarantee performance,” he said. Antimony trioxide is a metalloid, because it has metallic and nonmetallic characteristics.

Lanxess is monitoring the potential classification closely, Frank Grodzki, a company spokesman, told Bloomberg Environment.