A new study has linked phthalates, a substance used in some shampoos, lotions, air fresheners and children’s toys, with attention-deficit hyperactivity disorder. Although research on the health effects of phthalates (pronounced “thalates”) has been somewhat inconsistent, the latest study, published in Biological Psychiatry, adds to troubling findings about the chemical.

“These data represent the first documented association between phthalate exposure and ADHD symptoms in school-aged children,” Yun-Chul Hong, MD, PhD, senior author of the study, said in a statement. He and his colleagues came to their conclusions after measuring urine phthalate concentrations and evaluating ADHD symptoms in 261 Korean children, age 8 to 11 years. They found that the higher the concentration of phthalate metabolites in the urine, the worse the ADHD symptoms.

Some studies to date on phthalates have linked the chemical to hormone disruptions, birth defects, asthma and reproductive problems. Other studies have found no significant association between phthalate exposure and health risks.

In July 2008, the U.S. Congress passed legislation banning certain phthalates from children’s toys. But according to the U.S. Food and Drug Administration, which regulates the cosmetics industry, the organization “does not have compelling evidence that phthalates, as used in cosmetics, pose a safety risk.”

Currently, consumers can not definitively determine whether phthalates are present in certain products. The Fair Packaging and Labeling Act, which requires ingredient declarations on cosmetics sold at retailers, does not apply to individual fragrances or products used at salons, according to the FDA. The Household Product Labeling Act, introduced in September by Sen. Al Franken, D-Minn., would, if passed by Congress, require cleaning supply manufacturers to fully disclose all ingredients on their product labels.

Companies that have signed the Compact for Safe Cosmetics have agreed to post a full list of product ingredients. In addition, the Environmental Working Group's Skin Deep Database offers listings of product ingredients.