Summary:

ADEQ has initiated this rulemaking to adopt new rules or amend the existing rules in Arizona Administrative Code (A.A.C.) Title 18, Chapter 2, Article 13 (State Implementation Plan Rules for Specific Locations) that regulate the primary significant source of SO₂ (sulfur dioxide) emissions in the Miami nonattainment area (NAA), the Miami copper smelter owned and operated by Freeport-McMoRan. 

On Jan. 31, 2022, the Environmental Protection Agency (EPA) determined that the Miami SO₂ NAA failed to attain the 2010 1-hour SO₂ primary National Ambient Air Quality Standards (NAAQS) by the applicable attainment date of Oct. 4, 2018, based upon monitored air quality data from January 2015 to December 2017 (87 FR 4805 (Jan. 31, 2022)).

As a result of this determination, the State of Arizona is required to develop a revision to the Arizona SIP that includes, among other elements, SO₂ control measures that will provide for expeditious attainment of the SO₂ NAAQS in the Miami SO₂ NAA by Jan. 31, 2027.

This rulemaking is necessary to develop an EPA-approvable State Implementation Plan (SIP) for the Miami NAA in order to prevent EPA from imposing the sanctions (both emissions offsets and highway fund sanctions) required under the Clean Air Act for failure to submit a satisfactory SIP, to prevent the imposition of a federal implementation plan, and to improve air quality to protect public health.

Documents:

• Notice of Docket Opening | View >

Additional Resources:

• EPA “Finding of Failure to Attain” for the Miami SO₂ NAA | View >