A Win for UV/EB/LED in SCAQMD
In response to comments by RadTech, the South Coast Air Quality Management District (SCAQMD) modified its proposed Rule 1171 (Solvent Cleaning) to allow an exemption for UV/EB/LED operations. In its original form, the rule essentially banned the use of isopropyl alcohol or any other alcohol-based cleaners. Rule 1171 establishes Volatile Organic Compound (VOC) limits for commercial and industrial cleaning materials and applies to all solvent-cleaning operations taking place at any business in Southern California. The rule includes five primary categories of solvent-cleaning activities with VOC limits and applies to “any person who uses solvent materials in solvent-cleaning operations during the production, repair, maintenance or servicing of parts, products, tools, machinery, equipment or general work areas within South Coast AQMD.”
Several months ago, the SCAQMD proposed amendments to address the California Office of Environmental Health Hazard Assessment’s determination that two compounds, para Chlorobenzotrifluoride (pCBtF) and tert-Butyl Acetate (t-BAc), have carcinogenic health effects. Both are used in some solvent-cleaning materials. The rule rapidly transitions away from both solvents with a prohibition effective date of January 1, 2026, a sell-through end date of July 1, 2027, and a use-through end date of July 1, 2028.
In addition, the rule included a VOC limit of 100 grams per liter for the clean-up of UV/EB/LED equipment. The requirement would have made the use of alcohols for cleaning illegal in the South Coast. RadTech engaged in the rulemaking process to advocate for flexibility for members and their customers. The Association received feedback that customers unsuccessfully had tried to use low-VOC cleaners at their facilities for years, only to find that acetone-based cleaners leave residue on UV lamps and reflectors, thereby compromising the optical efficiency of the system. Additionally, acetone-based cleaners are highly flammable, and since UV/EB/LED equipment is electrical, any spark can lead to fires.
Industry representatives requested the inclusion of Product Weighted – Maximum Incremental Reactivity (MIR) VOC limits in grams of ozone produced per grams of VOC emitted (g O3/g VOC). According to the staff analysis, the MIR approach ensures that cleaning solvents used do not result in more ozone generation than the aerosolized isopropyl and denatured alcohol cleaners currently used.
During a preliminary hearing, Orange County Supervisor Janet Nguyen raised various issues related to the feasibility of the rule for the UV/EB/LED industry and instructed staff to address RadTech’s concerns. Staff acknowledged that equipment manufacturers recommend that energy-curing lamps and reflectors be cleaned with a cloth and an alcohol-based cleaner. The final version of the rule allows this as it includes an 800 g/L VOC limit for the cleaning of energy-curing lamps and reflectors. The staff report states, “This cleaning activity is infrequent and uses a small quantity of solvent when compared to the cleaning of other ink-application equipment used in the printing industry.”
In response to RadTech comments, the district added a definition for energy-curable inks as follows: “ENERGY CURABLE INK means an ink that dries upon exposure to visible light, ultra-violet light or an electron beam.”
The original version of the rule also limited the definition of water disinfection to Ozone generators. The International Ultraviolet Association (IUVA) advocated for the inclusion of Ultraviolet Light Treatment systems, which led to the following definition: “ULTRAVIOLET LIGHT TREATMENT means the process of using ultraviolet light to inactivate microorganisms (i.e., disinfection) or using ultraviolet light either with or without the addition of peroxide to oxidize contaminants (i.e., oxidation).”
Public water agencies requested the proposed usage limits and the ability to use liquid alcohol to clean UV light disinfection equipment. Staff heard from multiple large public water agencies, including the Los Angeles Department of Water and Power (LADWP) and Metropolitan Water District (MWD), to reach a consensus on feasible usage limits and Product Weighted – MIR-based VOC limits that allow the use of recommended cleaning solvents. The alcohol usage limit for UV Light Treatment Systems was increased from 16 gallons per year to 30 gallons per year (almost double the amount). In contrast, chlorination systems used for water treatment only are allowed five gallons per year.
RadTech efforts resulted in the following exemptions:
- Cleaning operations in Printing pre-press or Graphic Arts pre-press areas, including the cleaning of film processors, color scanners, plate processors, film cleaning and plate cleaning.
- The VOC limit for the cleaning of lamps and reflectors was increased from 100 grams per liter to 800 grams per liter to accommodate the use of isopropyl
Rita Loof
director of regional environmental affairs,
RadTech International North America
rita@radtech.org
