National Emission Standards for Hazardous Air Pollutants: Phosphoric Acid Manufacturing

This action finalizes an amendment to the national emission standards for hazardous air pollutants (NESHAP) for the Phosphoric Acid Manufacturing source category. The final amendment is in response to a petition for rulemaking on the mercury emission limit for existing phosphate rock calciners that was finalized on August 19, 2015 ("2015 Rule"). That emission limit was based on the maximum achievable control technology (MACT) floor for existing sources. All six of the existing calciners used to set this MACT floor are located at the PCS Phosphate Company, Inc. ("PCS Phosphate") facility in Aurora, North Carolina ("PCS Aurora"). PCS Phosphate asserted that data received since the rule's promulgation indicate that the MACT floor did not accurately reflect the average emission limitation achieved by the units used to set the standard. Based on these new data, the U.S. Environmental Protection Agency (EPA) is finalizing a revision of the mercury MACT floor for existing calciners.