Aviation hydraulic fluids Metal plating (hard metal plating) only in closed-loop systems Certain medical devices (such as ethylene tetrafluoroethylene copolymer (ETFE) layers and radio-opaque ETFE production, in-vitro diagnostic medical devices, and CCD colour filters) Fire-fighting foam Insect baits for control of leaf-cutting ants from Atta spp. and Acromyrmex spp. In 2019, it was decided to only keep one acceptable purpose: Insect baits with sulfluramid (CAS No. 4151-50-2) as an active ingredient for control of leaf-cutting ants from Atta spp. and Acromyrmex spp. for agricultural use only Canada In 2008 Canada proposed a ban on PFOS, only the second chemical proposed for a complete ban under the Canadian Environmental Protection Act. Europe Based on an OECD study on PFOS and a risk assessment by Europe's Scientific Committee on Health and Environmental Risks the European Union practically banned the use of PFOS in finished and semi-finished products in 2006 (maximum content of PFOS: 0.005% by weight). However, PFOS use for industrial applications (e.g. photolithography, mist suppressants for hard chromium plating, hydraulic fluids for aviation) was exempted. In 2009 this directive was incorporated into the REACH regulation. In the summer of 2010 PFOS was added to the regulation on persistent organic pollutants and the threshold was lowered to max. 0.001% by weight (10 mg/kg). United States In 2018 the State of Michigan established a legally enforceable groundwater cleanup level of 70 ppt for both PFOA and PFOS. In 2020 the Michigan Department of Environment, Great Lakes, and Energy (EGLE) adopted stricter drinking water standards in the form of maximum contaminant levels (MCLs), lowering acceptable levels from the 2018 enforceable groundwater cleanup levels of 70 ppt to 8 ppt for PFOA and 16 ppt for PFOS and adding MCLs for 5 previously unregulated PFAS compounds PFNA, PFHxA, PFHxS, PFBS, and HFPO-DA. In 2020, a California bill was passed banning PFOS and the following salts as an intentionally added ingredient from cosmetics: ammonium perfluorooctane sulfonate, diethanolamine perfluorooctane sulfonate, lithium perfluorooctane sulfonate and potassium perfluorooctane sulfonate. In March 2021 the U.S. EPA announced that it will develop national drinking water standards for PFOA and PFOS. In October 2021 the EPA proposed to designate PFOA and PFOS as hazardous substances in its PFAS Strategic Roadmap. In September 2022 the EPA proposed to designate as hazardous substances under the Superfund Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). See also 2005 Hertfordshire Oil Storage Terminal fire