US environmental regulators can now block new uses of old chemicals

US environmental regulators are proposing new rules for certain chemicals already on the market. Companies will now have to ask permission before using these chemicals in new ways, giving the regulators a chance to review the risks.

Before this, companies could often introduce new uses for existing chemicals without a full review, as long as the chemical itself was already approved. This change means US environmental regulators can now stop a company from using a chemical in a new way if they think it poses a risk. It shifts the burden of proof, making it harder to introduce new chemical applications without prior approval.