By Phil McKenna and James Bruggers Inside Climate News View Comments LOUISVILLE, Ky. — A proposed rule by the U.S. Environmental Protection Agency would require the chemical manufacturer Chemours to follow through on its promise to eliminate emissions of a climate super-pollutant from its Louisville Works chemical plant. The company pledged in March to eliminate 99 percent or more of its emissions of hydrofluorocarbon-23 (HFC-23), a greenhouse gas thousands of times more potent than carbon dioxide, from the plant by the end of 2022, after Inside Climate News inquired about emissions from the facility. The proposed rule, released earlier this month, would require Chemours to eliminate 99.9 percent of its HFC-23 emissions by Oct. 1, 2022, a deadline that could be extended for up to one year if the company can demonstrate it needed more time to make the fix.