The administration invalidated the Stream Protection Rule ( which prevented coal mining debris from being dumped into streams , groundwater and surface waters ) regulations which limited dumping of toxic wastewater containing metals , such as arsenic and mercury , into public waterways , regulations on coal ash ( carcinogenic leftover waste produced by coal plants ) , and an Obama-era executive order on protections for oceans , coastlines and lakes which was enacted after the Deepwater Horizon oil spill . The administration rolled back major Clean Water Act protections . Studies by the Obama-era EPA suggest that up to two-thirds of California 's inland freshwater streams would lose protections under the rule change . The EPA sought to repeal a regulation which required oil and gas companies to restrict emissions of methane , a potent greenhouse gas . The EPA granted a loophole allowing a small set of trucking companies to skirt emissions rules and produce trucks that emit 40 to 55 times the air pollutants of other new trucks . The EPA rejected a ban on the toxic pesticide chlorpyrifos ; a federal court ordered the EPA to ban the pesticide , because the EPA 's own staff had recommended banning it due to extensive research showing adverse health effects on children . The administration scaled back the ban on the use of methylene chloride , a lethal chemical . The EPA lifted a rule requiring major farms to report pollution emitted through animal waste
Deepwater Horizon oil spill
Deepwater Horizon oil spill
Presidency of Donald Trump