This action revises EPA's definition of volatile organic compounds (VOC) for purposes of preparing State implementation plans (SIPs) to attain the national ambient air quality standards (NAAQS) for ozone under title I of the Clean Air Act (CAA). This revision would add 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-trifluoromethyl-pentane [also known as HFE-7300 or L-14787 or C<INF>2</INF>F<INF>5</INF>CF(OCH<INF>3</INF>)CF(CF<INF>3</INF>)<INF>2</INF> ] to the list of compounds excluded from the definition of VOC on the basis that this compound makes a negligible contribution to tropospheric ozone formation. If you use or produce HFE-7300 and are subject to EPA regulations limiting the use of VOC in your product, limiting the VOC emissions from your facility, or otherwise controlling your use of VOC for purposes related to attaining the ozone NAAQS, then you will not count HFE-7300 as a VOC in determining whether you meet these regulatory obligations. This action may also affect whether HFE- 7300 is considered as a VOC for State regulatory purposes, depending on whether the State relies on EPA's definition of VOC. As a result, if you are subject to certain Federal regulations limiting emissions of VOCs, your emissions of HFE-7300 may not be regulated for some purposes.