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Asphyxiation in Confined Space

OSHA – A few minutes into the day, the crew noticed their operating engineer was missing and the manhole cover was removed. Looking down, they found the foreman unresponsive at the bottom of the hole. The workers quickly called emergency services. When they arrived, the fire department climbed down the 20ft manhole to retrieve the foreman. He was pronounced dead due to asphyxiation once they brought him back to the surface. The foreman had been in the business for 15 years.

Unfortunately, no precautions were taken to assess the conditions of the confined space, and no proper ventilation tools were used. The foreman also entered the space alone without an attendant to monitor his situation or alert emergency services at the first sign of danger. When measured, the atmosphere in the manhole contained 7.7% oxygen and 6.5% carbon dioxide. OSHA’s Confined Spaces in Construction standard defines a hazardous atmosphere as one with less than 19.5% oxygen and views anything with 4% or more carbon dioxide as Immediately Dangerous to Life or Health.

It is the responsibility of the employer to ensure the potential confined spaces that workers could be working in are identified, evaluated, and addressed before work begins. Furthermore, the employer must provide confined space training to all employees that will be entering the space. It is crucial to perform a pre-entry testing for oxygen content and potential toxic hazards and contaminants in addition to continuous testing throughout the day to verify that the conditions remain safe. This loss is tragic, and our hearts go out to the family and friends.

You can find more information on OSHA’s confined space standards here or you can go directly to their confined space compliance guide here.

Feel free to contact The Integrated Group for more information or consultation at 425-822-8500 or

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