Under Section 612 of the Clean Air Act (CAA), EPA’s Significant New Alternatives Policy (SNAP) program reviews substitutes within a comparative risk framework. The SNAP program evolves the list of alternatives as the EPA makes decisions informed by its overall understanding of the environmental and human health impacts as well as its current knowledge about available substitutes. It includes proposed rule listing for new substitutes and prohibiting certain high-GWP HFCs as alternatives under SNAP (4/18/2016) and rules prohibiting certain high-GWP HFCs as alternatives under SNAP. The EPA is driving cost-effective technology adoption through its authority under the Clean Air Act, but the United States should continue to work toward an international phase-down of high-GWP HFC use through the Montreal Protocol (WRI, 2015)
http://www.wri.org/blog/2015/03/reducing-hfcs-us-would-benefit-consumers-and-climate
repealed in 2018
https://www.federalregister.gov/documents/2018/04/27/2018-08310/protection-of-stratospheric-ozone-notification-of-guidance-and-a-stakeholder-meeting-concerning-the