For related articles and more information, please visit OCA’s Health Issues page, Food Safety Research Center page and our Coming Clean Campaign page.

Scientists have documented for the first time that several phthalates – controversial chemicals used to make vinyl and fragrances – are declining in people while several others are rising. The study, published today, is the first comprehensive, nationwide attempt to document trends in exposure to these widely used chemicals over the past decade.

The researchers said the results suggest that manufacturers may be reformulating products in the wake of a federal regulation and environmental groups’ campaigns.

Three compounds banned in U.S. toys and other children’s products in 2008 have declined. But since other phthalates are increasing, it’s possible that industries have substituted them in some products.

“Our findings suggest that interventions may be working, though legislation didn’t entirely predict which levels went up or down,” said Ami Zota, a George Washington University assistant professor of environmental and occupational health who led the research when she was at the University of California, San Francisco.

Phthalates have been linked to a variety of health effects in animal tests and some human studies, including hormone disruption, altered male genital development, diabetes, asthma, attention disorders, learning disabilities and obesity.

Chemical industry representatives said that the traces found in most products are small, and not likely to cause harm.

“Despite the fact that phthalates are used in many products, exposure is extremely low – much lower than the levels considered safe by regulatory agencies,” said Liz Bowman, a spokesperson for the American Chemistry Council, which represents manufacturers of phthalates and other chemicals.

The researchers analyzed the urine of more than 11,000 American adults and children between 2001 and 2010. They discovered that people are still widely exposed to phthalates; some were found in 98 percent of people tested.

Breakdown products of three phthalates that Congress banned from toys and other children’s products were significantly lower in 2010 than in 2001. One of the compounds, known as DEHP, found in some toys, blood bags and medical tubing, decreased 37 percent.