List of Hazardous Air Pollutants, Petition Process, Lesser Quantity Designations, Source Category List

EPA is amending the list of hazardous air pollutants (HAP) contained in section 112 of the Clean Air Act (CAA) by removing the compound methyl ethyl ketone (MEK) (2-Butanone) (CAS No. 78-93-3). This action is being taken in response to a petition submitted by the Ketones Panel of the American Chemistry Council (formerly the Chemical Manufacturers Association) on behalf of MEK producers and consumers to delete MEK from the HAP list. Petitions to remove a substance from the HAP list are permitted under section 112 of the CAA. Based on the available information concerning the potential hazards of and projected exposures to MEK, EPA has made a determination pursuant to CAA section 112(b)(3)(C) that there are "adequate data on the health and environmental effects [of MEK] to determine that emissions, ambient concentrations, bioaccumulation, or deposition of the substance may not reasonably be anticipated to cause adverse effects to human health or adverse environmental effects."