The Trump administration on Thursday will roll back regulations aimed at reducing emissions of the potent greenhouse gas methane from oil and gas operations.
This will be the latest move attempting to unwind environmental rules ahead of November's presidential election.
EPA Administrator Andrew Wheeler will formally rescind the 2016 Obama administration limits on oil and gas industry emissions of methane during a visit to Pennsylvania - an election swing state.
The move was criticized by environmentalists when initially proposed last August.
While the EPA is expected to retain some of the rules issued in 2012, it is also expected to remove sources of emissions, including the transport and storage of oil and gas, from regulation as well as requirements for companies to install equipment to detect methane leaks, according to a source familiar with matter.
It would also prevent any future regulation of methane from facilities built before 2015.
The American Petroleum Institute, a powerful fossil fuel lobby, has said it supports the final rule even if some of its larger members like Exxon, BP and Shell have called for mandatory methane regulations.
Smaller drillers say the rule is too costly for them to comply with.
Environmental groups said the move comes as scientific reports highlight the major role methane emissions play in worsening climate change.
These groups along with some state attorneys general will challenge the rollbacks in court.