"...and subject to Russian maintenance. And I’m here to tell you — Russian maintenance under the current oligarchy system isn’t any better than it was under the

"...and subject to Russian maintenance. And I’m here to tell you — Russian maintenance under the current oligarchy system isn’t any better than it was under the Soviet system." He is, as I read it, basically saying the methane may not be being properly isolated from the atmosphere so air may be leaking in. That said, you'd need a mega-massive-big input of oxygen contamination (wiki: "... 5–15% concentration [of air, not neat oxygen, IIUC] in a flammable or explosive mixture", and it would have to happen before gas pressurisation (or the methan would leak out, not air in). So I dunno.