EPA Final Rule Addressing NSPS For EAF & AOD Vessels at Steel Plants

On August 25^th, 2023, the United States Environmental Protection Agency (U.S. EPA) promulgated amendments to the Standards of Performance for New Stationary Sources (NSPS) for electric arc furnaces (EAF) and argon-oxygen decarburization (AOD) vessels. This action is in accordance with the Clean Air Act (CAA), which mandates that U.S. EPA review and possibly revise NSPS every eight years. Affected facilities that commence construction, reconstruction, or modification after May 16, 2022 must comply with newly promulgated requirements outlined in 40 CFR Part 60, Subpart AAb no later than August 25, 2023. Existing affected facilities that are subject to 40 CFR Part 60, Subparts AA and AAa must comply with promulgated revisions to those rules by February 21, 2024.

Background

The original NSPS, Standards of Performance for Steel Plants: Electric Arc Furnaces Constructed After October 21, 1974, and On or Before August 17, 1983 at 40 CFR Part 60, Subpart AA, was proposed in October 1974 and promulgated in September 1975. Subpart AA was reviewed by U.S. EPA in 1984, and a new Subpart AAa was established for affected EAF and AOD vessels that were constructed, reconstructed, or modified after August 17, 1983. Nearly 40 years later, it is no surprise that these standards have again been revised and updated.

What Revisions Were Made to the Standards for Particulate Matter?

During their review of Subparts AA and AAa, U.S. EPA ultimately identified several revisions related to definitions and monitoring procedures – most notably the opacity monitoring provisions related to shop opacity and the addition of an alternative opacity monitoring procedure in accordance with ASTM D752-16.

In addition to the changes promulgated under Subparts AA and AAa, U.S. EPA promulgated a new Subpart AAb that includes several substantial revisions as summarized below:

• 60.272b(a): The format for emissions limitations has been revised from a concentration basis [i.e., grains of particulate matter (PM) per dry standard cubic feet (dscf)] for each control device, to an “aggregate” basis (i.e., a total facility limit for PM from control devices in units of lb. PM/ton steel produced). The opacity limit for EAF melt shops during melting and refining activities has been reduced from 6% to 0%. However, the 6% opacity limit has been retained during charging and tapping activities. The control device opacity standard remains unchanged at 3%.
• 60.272b(b): The opacity limit for dust handling operations remains unchanged at 10%.
• 60.272b(c): Based on the decision from the 2008 United States D.C. Circuit Court of Appeals decision in the case of Sierra Club v. EPA, the exemption for limitations on opacity and other standards during startup, shutdown, and malfunction periods has been eliminated.
• 60.272b(d): Performance tests under Subpart AAb are required to be conducted every 5 years.

The new PM standard under Subpart AAb for PM reflects the best system of emissions reduction (BSER), which U.S. EPA determined is the use of a baghouse with a fabric filter for EAF and AOD vessels.  Likewise, the new opacity standards under Subpart AAb also reflect BSER, which U.S. EPA determined is the use of a canopy hood and fabric filter to capture emissions during melt shop activities.

 What Are the New Monitoring, Reporting and Testing Requirements?

U.S. EPA had originally proposed significant changes to the monitoring provisions under Subparts AA and AAa, and new monitoring provisions under Subpart AAb that included bag leak detection systems (BLDS), furnace static pressure monitoring, and volumetric flow and/or static pressure monitoring.  Commenters suggested that such monitoring would require significant capital investment by facilities and U.S. EPA ultimately did not finalize those proposed revisions under 40 CFR Part 60, Subparts AA, AAa, and AAb. U.S. EPA has retained monitoring provisions under to Subparts AA, AAa, and AAb that allow for fan amperage monitoring to be used as a surrogate for monitoring volumetric flow or static pressure when it is recorded on a basis more frequent than once per shift. Fan amperage monitoring is also required to be performed as frequently as damper position measurements during the initial or most recent performance test used to demonstrate compliance with the PM standards.

What Does This Mean for My Facility?

Affected facilities that are constructed, reconstructed, or modified after May 16, 2022 must demonstrate compliance with the emissions standards and reporting provisions found in Subpart AAb upon startup. Facilities that remain subject to Subparts AA and AAa should review the proposed revisions carefully so that compliance with the revisions is achieved by February 21, 2024.

ALL4 has many experts in the organization that can assist with conducting a compliance test, implementing monitoring systems, and implementing proper performance standards at your facility.  If you have questions or concerns about the standards and practices surrounding EAF and AOD vessels and you’d like to discuss them, feel free to contact your ALL4 project manager, or Daniel Hickey at Dhickey@all4inc.com. ALL4 monitors all updates published by U.S. EPA that have been published on this topic, and we are here to answer your questions and assist your facility with any aspect of regulatory compliance.