Landfill gas
Landfill gas means gas produced as a result of anaerobic decomposition of waste materials in the landfill. Landfill gas generally contains 40 to 60 percent methane on a dry basis, typically less than 1 percent non-methane organic chemicals, and the remainder being carbon dioxide.
Source
40 CFR § 98.6
Scoping language
All terms used in this part shall have the same meaning given in the Clean Air Act and in this section.