South Coast AQMD Proposed Amended Rule 1107: Key Updates and What You Need to Know

The South Coast Air Quality Management District (AQMD) is proposing to phase out the use of para-ChloroBenzotrifluoride (pCBtF) and tertiary-Butyl Acetate (t-BAc) in metal coating operations regulated under Rule 1107, with a final prohibition date of July 1, 2029. The preliminary draft rule 1107 is currently available for review.

A Working Group Meeting will be held on August 27, 2025, offering stakeholders the next opportunity to provide feedback before the rule is finalized. This public engagement point follows prior working group meetings held in August 2024, December 2024, and May 2025.

The proposed phase-out schedule for pCBtF and t-BAc in the preliminary draft rule is as follows:

• July 1, 2026: Final date to manufacture coatings containing pCBtF or t-Bac within AQMD’s jurisdiction.
• July 1, 2027: Final date to sell, supply, market, distribute, package, or repackage such coatings within AQMD’s jurisdiction.
• July 1, 2029: Final date to apply, blend, or possess such coatings at stationary source regulated with AQMD’s jurisdiction.

In addition to phasing out pCBtF and t-BAc, proposed changes in Rule 1107 include:

• Revised definitions to be aligned with Rule 1151 and clarification in the definition of “REDUCER OR THINNER”.
• Requirement that multi‑category coatings must meet the lowest Volatile Organic Compounds (VOC) limit among applicable categories.
• Prohibition of cadmium, hexavalent chromium, and Group II exempt compounds in regulated coatings.
• New labeling and administrative requirements for manufacturers, distributors, and sellers.

The preliminary draft rule does not propose changes to Table 1 VOC limits in Rule 1107; instead, AQMD is phasing out the use of the VOC “EXEMPT COMPOUNDS” pCBtF and t-BAc based on toxicity concerns identified by California’s Office of Environmental Health Hazard Assessment (OEHHA).

AQMD Regulatory Phaseouts for Use of pCBtF and t-BAc:

Historically, pCBtF and t-BAc have been used in metal coating operations to enhance coating performance and improve drying times. OEHHA assessed pCBtF and t-BAc for environmental and human health risks in 2018 and 2020. OEHHA toxicological assessments determined that both pCBtF and t-BAc have carcinogenic endpoints which prompted AQMD to evaluate the VOC “EXEMPT COMPOUND” status and/or initiate phaseout procedures for both compounds. AQMD did not reclassify pCBtF and t-BAc from their current status as a VOC “EXEMPT COMPOUND” under Rule 1107 and Rule 102. Instead, the proposed amended rule will phase out the use of pCBtF and t-BAc in metal coating operations.

The phaseout of pCBtF and t-BAc proposed under Rule 1107 is the latest phase out under a multi-rule initiative that includes:

• Rule 1168. Amended in November 2022 with an established phaseout timeline for the manufacture, sale, distribution, and use of pCBtF and t-BAc in adhesives and sealants following the OEHHA toxicological assessments.
• Rule 1151. Amended in November 2024 with a phaseout schedule for use of pCBtF and t-BAc in motor vehicle coating similar to that found in Rule 1107.
• Rule 1171. Amended in June 2025, solvent cleaning activities using pCBtF and t-BAc subject to the provisions of Rule 1171 subject to a tiered phase out with a final prohibition date of July 1, 2028.

What This Means for Your Facility:

If your facility performs metal coating operations subject to Rule 1107, it is important to:

1. Review your current materials to identify any coatings that contain pCBtF or t-Bac requiring action by your facility to comply beginning as early as 2026.
2. Participate in the August 27, 2025 workshop to engage with AQMD on feasibility, transition timelines, and sell-through provisions.
3. Consider subscribing to the AQMD Advisor Newsletter to stay up-to-date on rule updates.

By taking proactive steps now, your facility can better navigate the compliance challenges of the pCBtF and t-BAc phaseout under the amendments in preliminary draft Rule 1107.

If you have any questions about air quality compliance in the South Coast region of California, contact your ALL4 project manager, our California Office at 909.483.3300, or all4inc.com.