Disinfectant use has exploded during the coronavirus pandemic as people try to keep their hands and surfaces clean. But one family of cleaning chemicals is receiving scrutiny for potential health concerns. Quats, or quaternary ammonium compounds, are charged molecules that can kill bacteria, fungi, and viruses. Quats are effective disinfectants, but some researchers are raising alarm given recent research on the compounds’ possible human health and environmental effects, including fertility issues, endocrine disruption, occupational asthma, marine toxicity, and potential to spur antibiotic-resistant bacteria. And, while industry defends quats as safe, some states are taking notice and looking into regulations.