Phthalates, chemicals most commonly used to help harden plastics, have been on health experts' hazard radars for years. A growing body of research links these chemicals to reproductive development, low sperm count, asthma, and other health issues. Congress banned the use of three specific phthalates in plastic kids' toys in 2009, and more and more manufacturers have begun ousting specific phthalates from skin care, plastic containers, and other products. The good news: A new study finds that Americans are exposed to fewer of these restricted chemicals than we were a few years ago. However, the study also finds that our exposure to similar, unrestricted phthalates has skyrocketed due to manufacturers swapping in less studied, but potentially equally hazardous chemicals.

According to research from the University of California, San Francisco, these changes in phthalate use are already affecting human health. Researchers analyzed phthalate levels in urine samples from about 11,000 American adults and children between 2001 and 2010. They determined that exposure to the three phthalates banned from plastic toys – BBzP, DnBP, and DEHP – dropped off significantly. Similarly, levels of DEP, which has been nixed from many body-care products – and which also often contain the chemicals to help hold scents or colors – fell by 42 percent. However, exposure to other types of phthalates that manufacturers have started using more often has gone up. Specifically, DiNP exposure rose 150 percent, while DiBP tripled.

"It's hard to say for certain why exposure to some phthalates is going up and exposure to others is going down," says Tracey Woodruff, director of UCSF's Program on Reproductive Health and the Environment. "However, we do know that DEP has been a focus of market-based campaigns to remove it from personal-care products, which may in part explain the drop." She says DiBP (exposure increased 150 percent) is a common replacement for phthalates that have been banned or removed from the marketplace, likely accounting for its rise.

Manufacturers do not have to list phthalates on ingredient lists, so your best bet for steering clear is to skip lotions, colognes, laundry detergents, air fresheners, and other products that use synthetic fragrances, (for a full list of cosmetic products that contain phthalates, check out EWG's Skin Deep Database). Also, limit your use of plastic food and storage containers.