By the time the mix lands in treatment plants, it can teem with pharmaceuticals, hormones, pathogens, bacteria, viruses, protozoa and parasitic worms, as well as heavy metals like lead, cadmium, arsenic or mercury. It often includes PCBs, PFAS, dioxins, BPAs and dozens of other harmful substances ranging from flame retardants to hospital waste. And then it goes right on to the fields that grow your food.

The move by the EPA defies a court order that required the agency to establish a safe drinking-water standard for the chemical by the end of June. Instead of regulating the toxic chemical, the EPA overturned the underlying scientific finding that declared perchlorate a serious health risk for five million to 16 million people in the United States.

Senator James Inhofe, Republican of Oklahoma, claimed that the Environmental Protection Agency is releasing “propaganda” that is “brainwashing our kids,” during a CNN interview on Thursday.

“We want to deliver the services. We ought to make things clean,” Inhofe said. “But we ought to take all this stuff that comes out of the EPA that’s brainwashing our kids, that is propaganda, things that aren’t true, allegations.”