ATMOSPHERIC HAZARDS Prepared by Pretreatment Facility Inspection, Third Edition,1996 California State University, School of Engineering, Office of Water Programs, Sacramento, State of California. Confined spaces such as manholes, metering vaults and  other poorly ventilated areas may contain inadequate amounts of oxygen or collect toxic gases such as hydrogen sulfide, carbon monoxide, and hydrogen cyanide as well as explosive gases such as methane. Before entry into any confined space, always determine the atmosphere with an oxygen deficiency/combustion (LEL) hydrogen sulfide gas detection meter and continuously ventilate the confined space. Follow all confined space procedures and never enter when alone. .

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ATMOSPHERIC HAZARDS Prepared by Pretreatment Facility Inspection, Third Edition,1996 California State University, School of Engineering, Office of Water Programs, Sacramento, State of California.

Confined spaces such as manholes, metering vaults and  other poorly ventilated areas may contain inadequate amounts of oxygen or collect toxic gases such as hydrogen sulfide, carbon monoxide, and hydrogen cyanide as well as explosive gases such as methane. Before entry into any confined space, always determine the atmosphere with an oxygen deficiency/combustion (LEL) hydrogen sulfide gas detection meter and continuously ventilate the confined space. Follow all confined space procedures and never enter when alone.

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