Dry cleaning is an industry that dates back to the 1600s—when turpentine was used to clean fabrics. But now it's an industry in transition amid growing demand for dry cleaning solvents that are less harmful to humans and the environment. At the center of this is a push to replace perchloroethylene (PERC), which is the most commonly used dry cleaning solvent. A range of new chemicals have come on the market, but there are risks because scientists are rarely able to assess a solvent's long-term health effects before it's used commercially. In this week's episode we speak with Diana Ceballos, research scientist at the Center for Health and the Global Environment at Harvard T.H. Chan School of Public Health. We'll discuss why new dry cleaning solvents pose challenges for the industry and regulators, and what the U.S. can learn from Europe when it comes to chemical safety.