Water and Wastewater Terms Beginning D

A B C D E F G H I J K L M N O P Q R S T U V W Y Z

dangerous air contamination

An atmosphere presenting a threat of death, injury, acute illness, or disablement due to the presence of flammable or explosive, toxic, or otherwise injurious or incapacitating substances. Dangerous air contamination due to the flammability of a gas, vapor, or mist is an atmosphere containing the gas, vapor, or mist at a concentration greater than 10 percent of its lower explosive limit. Dangerous air contamination due to a combustible particulate is an atmospheric concentration that meets or exceeds the particulate’s lower explosive limit. Dangerous air contamination due to the toxicity of a substance is the atmospheric concentration that could result in employee exposure in excess of the substance’s permissible exposure limit.


NOTE: A dangerous situation also occurs when the oxygen level is less than 19.5 percent by volume (oxygen deficiency) or more than 23.5 percent by volume (oxygen enrichment).