The American Chemical Society, which oversees the U.S. chemical industry, says it has approved about 200 chemicals that can be used to treat or prevent disease.
Those include more than 100 known carcinogens.
The group said it expects to approve about 500 chemicals by the end of 2018.
But the new rules mean manufacturers can now use only five chemicals on the market.
“These are extremely safe, but they’re not the safest chemicals that we can use,” said Robert L. Johnson, president and CEO of the American Chemistry Council, a trade group.
The chemicals must also be approved by the Food and Drug Administration, which is in charge of approving pharmaceuticals and other medical products.
The FDA has been in the middle of reviewing the chemical labels.