South Coast Air Quality releases proposed rule amendments for phasing out solvents
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The South Coast Air Quality Management District has released its draft proposal of amendments to Rule 1151 which will phase out the use of solvents tert-butyl acetate (t-BAC) and para-chlorobenzotrifuloride (pCBtF) in paint manufacturing.
The California Office of Environmental Health Hazard Assessment has deemed the solvents as potential carcinogens, according to the AQMD.
During Phase I, affected facilities will be allowed to use coatings formulated to meet the less stringent U.S. National Rule Limits, which do not utilize pCBtF or t-BAc in their formulations and are, therefore, less expensive, the AQMD wrote in its draft socioeconomic impact assessment of the proposed amendments.
“This will lead to the phase-out of pCBtF and t-BAc containing coatings, while resulting in a temporary increase in VOC emissions. During this phase, affected facilities will experience cost savings.
“During Phase II, affected facilities will begin to transition from the Phase I higher-VOC coatings to reformulated, low-VOC coatings that do not contain pCBtF or t-BAc. In Phase II, reformulation costs and any higher material costs are expected to be passed on to the affected facilities through higher costs per gallon of the reformulated coating. While Phase II coatings are expected to be more expensive than Phase I coatings, it is unclear whether Phase II coatings will continue to be more expensive than the currently used coatings in the long run.”
The analysis also includes a Phase 0 period, referring to the pre-adoption time when the coatings used must meet the existing Rule 1151 limits and generally contain t-BAc or pCBtF.
“Based on feedback from automotive coating manufacturers, the coatings currently used in Phase 0 are about 10% more expensive than the coatings that will be allowed to be used during Phase I. For the reformulated coatings that will meet the proposed Phase II limits, the expected cost is assumed to be approximately the same
as the present-day cost.
“Put simply, since pre-adoption prices are already higher in than coatings that meet the U.S. National Rule Limits, affected facilities are expected to experience a period of cost savings followed by a period of higher costs as VOC coatings are reformulated as required by PAR 1151.”
Amendments to the rule include but are not limited to:
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- Several new and/or modified definitions including: adhesion promoter, epoxy primer, gloss clear coating, matte clear coating, and maximum incremental reactivity as well as several others;
- VOC content limit revisions; and
- Alternative VOC content limits for color coatings of 720 g/L that are supplied in half-pint or smaller containers, provided that the coating does not contain more than 0.01% by weight of either pCBtF or t-BAc.
AQMD staff wrote in a report released last week that the alternative VOC content limits for color coatings is intended to address solvent-based coatings use by smaller autobody shops. Shops will be given additional time to make the transition to water-based alternatives, until Jan. 1, 2030, the report says.
Color coatings that comply with the alternative VOC content limit pursuant to paragraph (d)(4) and that are manufactured prior to Jan. 1, 2030 may be sold, supplied, or offered for sale up to Jan. 1, 2032, and used until
Jan. 1, 2033.
Cost savings
During phase I, affected facilities will be allowed to use coatings that are less expensive than the coatings used in Phase 0, resulting in cost savings.
Depending on the automotive coating category, affected facilities will be required to transition from phase I coatings to reformulated phase II coatings in 2028, 2029, or 2030. This would result in an increase in costs relative to
Phase I, and parity in costs relative to Phase 0, according to AQMD’s draft socioeconomic impact assessment.
The total cost savings over the forecast period is estimated at $260.45 million and $239.70 million with a 1% and 4% discount rate, respectively.
The average annual cost savings is estimated to be $13.40 million, regardless of the assumed interest rate.
The overall impact on production cost and delivered prices in the region is not expected to be substantial, the AQMD said.
The rule changes would affect 2,880 facilities in the South Coast AQMD jurisdiction that apply automotive coatings to motor vehicles.
The current rule amendment process began in September 2023. AQMD staff held four working group meetings and multiple individual meetings with industry stakeholders and representatives.
Staff also distributed a survey to the coating manufacturers requesting product data for each automotive coating category.
Five of the seven major automotive coating manufacturers responded to the survey. AQMD does not provide the names of those that responded.
Most manufacturers reported that a large portion of their automotive coatings categories meet the current Rule 1151
VOC limits using pCBtF and t-BAc.
In summary, AQMD said the major findings of the survey include:
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- 62% of the reported automotive coatings contain pCBtF and less than 1% contain t-BAc;
- 71% of the reported automotive coatings are solvent-based and 29% are water-based;
- Only two automotive categories reported using t-BAc: adhesion promoters and truck bedliners and these two categories also reported using quantities of pCBtF ranging from 16-34%;
- Seven automotive coating categories reported only containing pCBtF in their formulation: clear coatings, color coatings, pretreatment coatings, primers, single-stage, uniform finish coatings, and underbody coatings. The remaining two categories: multi-color coatings and temporary protective coatings were not reported in the survey.
The proposal includes a longer phase-out period for color coatings to allow for end-user training, according to AQMD.
“Most large autobody shops are currently using water-based color coatings and small shops can take advantage of the half-pint alternative VOC limit until the Phase II limits take effect. Medium-sized shops are still using solvent-based color coatings, and the half-pint containers will not work in the existing mixing equipment.
“Staff visited many shops that transitioned to water-based coatings over a decade ago. While they agree that water-based coatings are good products, training was needed to learn how to properly apply the coatings. Since the large shops already use water-based coatings and small shops will likely opt for the cheaper half-pint high-VOC coatings, staff does not anticipate there will be a lot of pCBtF-based color coatings manufactured for use in the South Coast AQMD after May 1, 2025.”
A public hearing on the proposed rule amendments will be held on Nov. 1 at 9 a.m. in person and virtually. At that time, the South Coast AQMD Governing Board will hear public comments.
Instructions on how to participate are posted on South Coast AQMD’s website.
Images
Featured image credit: Wengen Ling/iStock
Charts provided in Rule 1151 South Coast AQMD reports
More information
South Coast Air Quality Management District proposes phase-out of some paint solvents by 2028