The Environmental Protection Agency has decided not to regulate a key ingredient of rocket fuel that has been found in the drinking water of millions of Americans.The chemical perchlorate can interfere with normal thyroid function and may cause cancer.

The EPA also chose not to set safety standards for other chemicals that are used to disinfect drinking water.

The EPA announced the decisions by burying the information at the bottom of a press statement quietly released late Friday afternoon.

Erik Olseon of the Natural Resources Defense Council said, “This is nothing less than a sneak attack on America’s drinking water safety. These are major regulatory decisions that they essentially were trying to hide from the American public.”