48 CFR §23.001

As used in this part— Environmental means environmental aspects of internal agency operations and activities, including those aspects related to energy and transportation functions. Greenhouse gas means carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, nitrogen trifluoride, or sulfur hexafluoride. Toxic chemical means a chemical or chemical category listed in 40 CFR 372.65.