Researchers have developed safer alternatives to the phthalate plasticizers used to enhance the suppleness, flexibility, and longevity of plastics. Phthalates leach out of plastics into food, water, and the environment, and there is mounting evidence suggesting that phthalate exposure can lead to a variety of health problems. The new chemicals are effective as plasticizers for polyvinyl chloride (PVC) but can't leach out of PVC products because they are chemically bonded to the polymer chain.