Publicly owned treatment works (POTWs) collect wastewater from municipal, commercial and industrial facilities, transport it through a series of contributor pipes, known as a collection system, and deliver it to the treatment plant. Regulations prohibit these facilities from discharging flammable or explosive wastes from their processes into the liquid collection system. In addition to fire and explosion hazards, these wastes can affect the efficient and effective operation of the treatment facility. The only certain way to guard against these hazards is to continuously monitor for flammable gases and vapors.