As reported in our May 14, 2025, blog item, on May 12, 2025, the U.S. Environmental Protection Agency (EPA) denied a petition filed under Section 21 of the Toxic Substances Control Act (TSCA) seeking to prohibit the use of hydrogen fluoride in domestic oil refining through a TSCA Section 6(a) rulemaking. The Natural Resources Defense Council (NRDC) announced on July 9, 2025, that after EPA denied their petition, community and environmental non-governmental organizations (NGO) filed suit in the U.S. District Court for the Central District of California “to force [EPA] to address the threat of an unnecessary and dangerous chemical used in dozens of American refineries despite its potential to form toxic acid clouds.” The Clean Air Council (CAC), Communities for a Better Environment (CBE), and NRDC claim that more than forty oil refineries across the country use hydrogen fluoride, even though several refineries have started to replace it with safer commercial-scale alternatives.