US environmental regulators can now block new chemicals before they hit the market

The US environmental regulators can now require companies to get approval before making or importing certain new chemicals. This means the agency can evaluate the risks of these chemicals before they are widely used, rather than after problems emerge.

For decades, new chemicals could often enter the market with little oversight, and regulators had to prove harm after the fact. This rule flips that dynamic for specific substances. It shifts the burden of proof, making it harder for companies to introduce potentially harmful chemicals without prior review and approval.