Confined Space Hazards for Sewage Treatment Workers 1989 CUPE Canada

Confined-space entry is one of the most common and one of the most serious hazards faced by sewage treatment workers. A universal definition of a confined space is elusive. In general, however, a confined space is an area with limited means of entry and egress that was not designed for continuous human habitation and that does not have adequate ventilation. Hazards occur when the confined space is associated with a deficiency of oxygen, the presence of a toxic chemical or an engulfing material, such as water. Decreased oxygen levels can be the result of a variety of conditions including the replacement of oxygen with another gas, such as methane or hydrogen sulphide, the consumption of oxygen by the decay of organic material contained in the waste water or the scavenging of oxygen molecules in the rusting process of some structure within the confined space. Because low levels of oxygen in confined spaces cannot be detected by unaided human observation it is extremely important to use an instrument that can determine the level of oxygen before entering any confined space. When individuals enter an atmosphere with oxygen levels below 16.5% they may immediately become too disoriented to get themselves out and eventually succumb to unconsciousness. If the oxygen depletion is great enough individuals can become unconscious after one breath. Without rescue they can die within minutes. Even if rescued and resuscitated, permanent damage can occur. Lack of oxygen is not the only hazard in a confined space. Toxic gases can be present in a confined space at a concentration level high enough to do serious harm, even kill, despite adequate oxygen levels. The effects of toxic chemicals encountered in confined spaces are discussed further below. One of the most effective ways to control the hazards associated with low oxygen levels (below 19.5%) and atmospheres contaminated with toxic chemicals is to thoroughly and adequately ventilate the confined space with mechanical ventilation prior to allowing anyone to enter it. This is usually done with a flexible duct through which outside air is blown into the confined space. Care must be taken to ensure that fumes from a generator or the fan motor are not also blown into the confined space. For more information, read the Confined Space Entry Hazard Alert at http://www.mass.gov/lwd/docs/dos/mwshp/hib405.pdf . This is clipped from the 1989 video, More Than a Job: Health & Safety for Sewage Treatment Workers (29 minutes) produced for the Canadian Union of Public Employees (CUPE) representing 600,000 working women and men across Canada.

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Education

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• Confined
• space
• health
• safety
• hazard
• sewage
• treatment
• worker
• water
• wastewater
• public
• union
• labor
• CUPE
• Canadian
• Union
• of
• Public
• Employees
• Canada
• Ontario
• OSHA
• egress
• toxic
• oxygen
• Work