. . . "In some the carbon footprint of toxic gas removal, compression, condensate separation, processing, and other processes are cumulatively calculated (NETL; U.S. National Energy Technology Laboratory [11], Stephenson et al. [12]) and in others past industrial studies are cited (Burnham et al. [13]);jThe amount of carbon dioxide that is vented at the NG processing plant is calculated as the carbon foo" . .