The EPA is approving revisions to the Tennessee Department of Environment and Conservation's definition of Volatile Organic Compounds submitted on February 3, 1999 by the state of Tennessee. These revisions are designed for the State Implementation Plan (SIP) to attain the national ambient air quality standards (NAAQS) for ozone under title I of the Clean Air Act (CAA). The additional compounds HFC43-10mee, HCFC-225ca, and HCFC-225cb are added to the list of exempt compounds on the basis that they have negligible contribution to the tropospheric ozone formation.