Wiktionary
swamp gas
n. (context colloquial English) hydrogen sulfide
Usage examples of "swamp gas".
Odors lingered in the stagnant air, as land-bound as shadows, commingling but still distinct enough to identify: swamp gas, decay, venom flowers, sweat, fear.
Cautious, you mean anything of what you say or you just full of swamp gas?
After a few minutes, her eyes adjusted to the blackness and she was able to see outlines and swamp gas.
The air was heady with the luminous scent of magnolias and the fetor of swamp gas.
Which was that a globe of shimmering swamp gas materialized above his ugly hat.
His tattoos were all in place, the restraining net was gone, and his mouth tasted of swamp gas.