The Environmental Protection Agency has declined to limit the amount of ammonium perchlorate that can contaminate drinking water before it becomes unsafe for consumption, The New York Times reports. The chemical, a toxic ingredient in NASA rocket fuel, causes brain damage in babies when ingested, and its cleanup, which would span the nation and cost billions, has been the subject of debate for decades. EPA chairman Andrew Wheeler’s decision to declare it “not in the public interest” to regulate runs contrary to a court order mandating the establishment of a safe perchlorate threshold by June 2020. The Obama administration said that it would regulate the chemical in 2011, and some states such as California and Maryland have already done so.