Phthalates, a family of chemicals used in everything from plastics to beauty products, have been detected in humans at levels that some scientists believe are worrisome. Researchers at the Centers for Disease Control and Prevention tested urine samples from people around the U.S. and were surprised to find phthalates at much higher levels than other pollutants routinely detected in people, such as PCBs. Phthalates, which may cause birth defects and disrupt hormonal systems, have been banned from use in baby toys in Europe, and some American manufacturers have voluntarily removed them from baby items. But this latest research, which is expected to be published in a peer-reviewed journal this fall, could prompt calls for a broader crackdown on the chemicals.