ABSTRACT
This chapter focuses on atmospheric hazards found in confined spaces. Categories identified in the National Institute for Occupational Safety and Health and Occupational Safety and Health Administration (OSHA) reports included toxic gases and vapors, oxygen deficiency and enrichment, and flammable and explosive atmospheres. The OSHA report on confined spaces listed the toxic chemical agents. Specific toxic agents included carbon dioxide, carbon monoxide and hydrogen sulfide, and vapors from hydrocarbon and halogenated hydrocarbon solvents. Accidents involving toxic and asphyxiating atmospheres resulted from acute exposure to rapidly acting chemical agents. Chemical agents exert acute effects by two main actions: asphyxiation and anesthesia. Confined spaces are inherently dangerous workplaces and the sites of many fatal and nonfatal accidents. The hazards in confined spaces arise from many factors: the geometric shape that forms the space, internal configuration, bulk and residual contents, active and passive chemical and physical processes, and mechanical and other equipment.
