"Hydrogen sulfide (H₂S)" means a colorless gas with a rotten egg odor often produced by the decay of plant or animal material. Most hydrogen sulfide in the air comes from natural sources such as decaying organic matter, seaweed on the beach or stagnant water in bogs. It is released from sewage sludge, liquid manure, sulfur hot springs, natural gas, and synthetic fuels. (Added by Amended Ord. 06-074, Nov. 8, 2006, Eff date Nov. 26, 2006).