Opinion ID: 4020089
Heading Depth: 4
Heading Rank: 5

Heading: The Health-Based Emissions Limits for HCl

Text: Although the EPA set numeric MACT standards to control HCl emissions, see 2013 Major Boilers Rule, 78 Fed. Reg. at 7,193-98 tbls.1 & 2, in an earlier iteration of the Major Boilers Rule, the EPA did not set MACT standards for HCl. See National Emission Standards for Hazardous Air Pollutants for Industrial, Commercial, and Institutional Boilers and Process Heaters (2004 Boilers Rule), 69 Fed. Reg. 55,218, 55,227 (Sept. 13, 2004). Instead, the Agency opted for a less stringent health-based emissions limit under section 7412(d)(4). See id. The EPA changed course after concluding that HCl emissions posed health concerns the Agency had not previously considered—in particular, the EPA feared the “potential cumulative public health and environmental effects” of HCl emissions, 2011 Major Boilers Rule, 76 Fed. Reg. at 15,643-44 (emphasis added)—and after recognizing that it did not have the requisite data to weigh adequately the newly identified health risks. 20