November 17, 1995

South Coast Air Quality

Management District Board

INTRODUCTION

The United States Environmental Protection Agency (EPA) and California Air Resources Board (ARB) have determined that acetone, ethane, parachloro-benzotrifluoride (PCBTF), and volatile methylated siloxanes (VMS) have negligible photochemical reactivity and should be considered exempt compounds. The South Coast Air Quality Management District (AQMD) is therefore proposing to include these materials in the definition of Exempt Compounds in Rule 102 - Definition of Terms. The AQMD also proposes to add minor clarifying language, including definitions of Executive Officer and particulate matter of 10 microns or less (PM10).

The proposed amendment of the exempt compound definition in Rule 102 will supersede all exempt volatile organic compound (VOC) definitions in all other AQMD regulations including, but not limited to, Regulations III, IV, XI, and XIII; however, the proposed changes will have no impact on existing emission limits.

The AQMD received tremendous interest regarding the addition of these materials to the exempt compound list, mostly from companies manufacturing paints, coatings, and solvents as well as the aerospace, wood furniture, paper coating, and foam blowing industries. Although a public workshop was not required, AQMD staff did contact interested parties to request comments and answer questions.

EPA requested public input regarding their proposed exemption of these materials on several occasions during the last two years. The supporting EPA documents for VMS and PCBTF contained no public opposition (40 CFR Part 51 Vol. 59, No. 192, effective December 5, 1994). Fifty-two public comments were received for acetone (40 CFR Part 51 Vol. 60, No. 116, effective June 16, 1995), and 80 percent of them were in favor of the exemption proposal. The negative comments came from industries that developed low solvent technologies and from individuals who felt acetone was too reactive to be considered exempt. EPA responded that acetone has negligible reactivity and this proposal does not restrict the use of other low-solvent technologies. In addition, EPA documents report that all four materials have virtually zero stratospheric ozone depletion potential and insignificant global warming potential.

DISCUSSION

Acetone, PCBTF, and VMS are estimated to replace up to four tons per day of compounds that are photochemically reactive, nine tons per day of ozone depleting compounds (ODC), and one ton per day of toxics. These replaced compounds include ketones, toluene, xylene, 1,1,1-trichloroethane, perchloroethylene, and methylene chloride. Ethane will not serve as a replacement material for other compounds and its current use should not be impacted. The primary sources of ethane emissions are refineries and natural-gas-handling facilities. Ethane is not commercially available in the United States.

Acetone is expected to be used as a replacement for solvents used in coating, hand wiping, stripping, and surface cleaning operations, and as a blowing agent in foam manufacturing. Acetone is volatile, odorous, and flammable, but is relatively inexpensive at $2.10 a gallon. A potential concern with acetone is its ability in high concentrations to be a precursor to the formation of formaldehyde. Both EPA and ARB staff anticipate, however, that the substitution of acetone may reduce formaldehyde concentrations because acetone is less reactive than the materials it will replace, such as toluene and xylene. ARB plans to sample acetone concentrations at their six monitoring stations located in the AQMD to determine if any emission increase occurs.

VMS is a class of compounds currently consisting of 14 materials of which six are commercially available. VMS is flammable and costly, at a current price of $65 a gallon. It is a potential replacement for ODC and VOC materials in paints, consumer products, and cold solvent cleaning.

PCBTF is also costly at $21 a gallon. It is flammable, odorous, and moderately toxic. Cal/EPA's Office of Environmental Health Hazard Assessment has determined, however, that its toxic impacts are not expected to result in specific health effects. Current PCBTF toxicity data on humans is subject to further study. PCBTF is a potential replacement for ODC and VOC materials in paints, consumer products, and cold solvent cleaning.

The Exempt Compounds definition divides materials into Groups I and II. Both Groups I and II include exempt compounds of VOC, but Group II compounds are either toxic, potentially toxic, upper-atmosphere ozone depleters, or cause other environmental impacts. Acetone and ethane, are proposed to be placed in Group I. Information received by the Office of Environmental Health Hazard Assessment after the proposed amended rule was set for hearing indicates that additional toxicity testing of VMS and PCBTF is preferred. Based on this data, staff believes that these compounds are better placed in Group II of the Exempt Compounds definition.

The proposed amendments will encourage current users of known toxic and reactive VOC to switch to the four compounds. The majority of the switches will be to acetone because of its lower price. Thus, there will be savings to the affected facilities. On the other hand, the switches will lower the AQMD's revenue from emission fees assuming Rule 301 is amended to comport with this change. Therefore, the amendments to this rule are a cost-effective alternative since the proposed changes are not mandatory.

CONCLUSION

Pursuant to the California Environmental Quality Act (CEQA) and the AQMD's Certified Regulatory Program (Rule 110), the AQMD has prepared appropriate CEQA documentation for the proposed amendments consisting of a Draft Environmental Assessment (EA). The Draft EA was released for public review and comment from September 20, 1995 through October 20, 1995. The Final EA includes responses to all comments received on the Draft EA. The Final Staff Report, Final Socioeconomic Assessment, and Final EA are attached.

THEREFORE IT IS RECOMMENDED THAT YOUR BOARD

--Amend Rule 102 - Definition of Terms, as proposed, in accordance with the attached Resolution; and

--Certify the Environmental Assessment for Proposed Amended Rule 102 - Definition of Terms.

Respectfully,

James M. Lents, Ph.D.

Executive Officer

Attachments

PL:CC:MM:SJ:sr