The San Diego County Air Pollution Control District (District) has made a preliminary decision to revise its list of exempt compounds as outlined in Table 1 of Rule 2 and its list of Toxic Air Contaminants (TAC) as specified in Table III of Rules 1200 and 1210. Exempt compounds are organic compounds that have been determined to have low or negligible photoreactivity and are not regulated as volatile organic compounds (VOC). The newly classified TACs are compounds that have been identified as having potential acute noncancer impacts.
The District has followed EPA precedent in classifying trans-1,3,3,3-tetrafluoropropane (HFO-1234ze) and trans-1-chloro-,3,3,3-tetrafluoropropene (HFO-1233zd) as exempt compounds. These two compounds are primarily used as aerosol propellant, degreasers, blowing agents, and refrigerants. The revision shall be made after the specified legal requirements for public noticing are met.
The District has followed the recommendations of the California Office of Environmental Health Hazard Assessment (OEHHA) in recognizing the potential impacts of methylene diphenyl isocyanate and toluene diisocyanates, including toluene-2,4-diisocyanate and toluene-2,6-diisocyanate. Methylene diphenyl isocyanate is used in the preparation of polyurethane resin and spandex fibers, and to bond rubber to rayon and nylon. Toluene diisocyanates are used primarily to make flexible polyurethane foam products, but can also be found in adhesives, sealants, coatings, and elastomers.
Additional information regarding these revisions can be found here on the District website. The District is accepting written comments for a period of 30 days ending on June 13th, 2016. Questions or comments may also be directed to Angela Ortega via email, or by phone at (858) 586-2753.