Sewer gas Sewer gas Sewer gas is a complex mixture of toxic and nontoxic gases produced and collected in sewage systems by the decomposition of organic household or industrial wastes, typical components of sewage. Sewer gases may include hydrogen sulfide, ammonia, methane, esters, carbon monoxide, sulfur dioxide and nitrogen oxides. Improper disposal of petroleum products such as gasoline and mineral spirits contribute to sewer gas hazards. Sewer gases are of concern due to their odor, health effects, and potential for creating fire or explosions. Sewer gas is typically restricted from entering buildings through plumbing traps that create a water seal at potential
Merrimack Valley gas explosions Merrimack Valley gas explosions On September 13, 2018, excessive pressure in natural gas lines owned by Columbia Gas caused a series of explosions and fires occurred in as many as 40 homes, with over 80 individual fires, in the Merrimack Valley, Massachusetts towns of Lawrence, Andover, and North Andover. One person was killed and 30,000 were forced to evacuate their homes. According to the NTSB's preliminary report, customers in the accident area received gas from a low-pressure (0.5 psi) distribution network which, in turn, was fed from a high-pressure (75 psi) main pipeline via regulators controlled by sensors measuring pressure