Atmospheric Hazards within a Confined Space
Atmospheric hazards within a confined space are the leading cause of entrant fatalities. As we know, workers working inside of a confined space will often experience restrictions in movement, have only one way in and out, and working in an environment that isn’t meant for continuous occupancy.
Let’s review the deadly killer, atmospheric hazards which are often odorless gasses that can sneak up on an entrant without them knowing it.
PRESS RELEASE - Cal/OSHA Cites Four Employers $1.75 Million for Safety Violations in Death of Worker at Valero Refinery
An incident last November 2021 caused the life of a 35-year-old worker. The worker lost consciousness after descending into a regenerator overflow well at the Benicia refinery to evaluate the condition of the well interior and perform cleaning operations in advance of a welding crew.
He was discovered within the regenerator, equipped with fall protection, and retrieved by a refinery emergency rescue crew. He received on-site medical attention from the Benicia Fire Department and the Valero Refinery Fire Department, but they were unable to revive him.
The culprit is the odorless gas argon, which was leaking from a welding torch left in the well and replaced the oxygen inside the space.
Argon in an open atmosphere is not extremely dangerous as its placard rating for Health is 1, Flammability is 0, and Reactivity is 0. When used within a confined space, everything changes as it will replace the oxygen which can drop to deadly levels as we see from the above example.
Common Toxic Gases
Toxic gases can be created by items that are purposefully utilized or stored in confined spaces, by natural processes, mistakenly introduced into the space, or, in the case of sewers and big, linked systems, make their way into the area being worked on.
In a confined space this may include harmful materials due to the type of manufacturing method used, the biological and chemical "breakdown" of the product being stored in a tank, maintenance activities (such as welding) carried out in the confined area, and other factors.
Common types of toxic gases encountered in confined spaces are:
Hydrogen Sulfide - "Sewer gas" is a colorless gas with a rotten egg smell. Numerous fatalities in restricted spaces have been connected to excessive exposure. Because hydrogen sulfide impairs our ability to smell, some people may believe that the gas has left the area. Asphyxiation is brought on by hydrogen sulfide, which prevents the exchange of oxygen at the cellular level.
Carbon monoxide - is produced when carbon-based fuels are burned, and it has no scent or color (gas, wood). The body's ability to distribute oxygen to every region of the body is hindered by carbon monoxide.
Solvents - many solvents, including kerosene, gasoline, paint removers, degreasers, etc., are not only flammable but can also have negative effects on the central nervous system (CNS) if inhaled in high quantities. Dizziness, drowsiness, lack of focus, disorientation, headaches, coma, and death are examples of CNS effects.
Many workplaces have hazards related to confined spaces. Employers are required to recognize and label confined spaces, create and maintain emergency response plans for the workplace, and train employees and supervisors.
How to Protect Entrants
The solution is for the most part simple but often not followed or not followed correctly. That solution is to test the atmosphere before and during entry. If you or your crew do not know how to properly test a space or use the atmospheric monitor that is provided to you then learn it! Learn how to test the different stratospheres.
