There are significant quantities of low-quality or subquality natural gas in the United States that have not been entered into the resource data base. The fields encountered have been shut in or abandoned for lack of a market. Such gas fields notably contain nitrogen in higher concentrations and also may contain carbon dioxide and/or hydrogen sulfide. There are, in fact, high-nitrogen-content natural gas occurrences in southwest Arkansas, northern Texas, West Texas and the Panhandle region, eastern New Mexico and eastern Colorado, western Kansas and north central Oklahoma—not to mention central California and other locales. A detailing of this subquality reserve would be most useful, as would new and improved methods for gas separation, particularly of nitrogen.