Fatality Statistics - Causes

According to the same NIOSH study, 56 percent of the confined space fatalities studied were caused by atmospheric conditions. These include oxygen deficiency (17 percent of all atmospheric-related fatalities), hydrogen sulfide (14 percent), methane (10 percent), inert gases (9 percent), sewer gases (7 percent), carbon monoxide (7 percent), and other unspecified conditions. Tanks are the most common place to encounter atmospheric hazards, making up 29 percent of the total atmospheric fatalities. Sewers, pits, and silos follow closely behind. While many of these fatalities affected people outside of the construction industry, all of these locations are built and maintained by construction crews. The construction industry is the second most prone to atmospheric fatalities in confined spaces.

Another 34 percent of all confined space fatalities were caused by engulfment in a loose material. Grain made up over half of these fatalities, causing 124 of the 227 deaths by engulfment. Other common materials can cause engulfment as well, such as sand (11 percent of engulfment fatalities); gravel, clay or cement (10 percent); sawdust (5 percent); and other agricultural products like silage or fertilizer (11 percent). These deaths are much less common in construction than in other industries, with only about 10 percent of the total fatalities occurring in construction-related jobs, but they do still happen and can be avoided.

The final 10 percent of confined space fatalities are due to other causes, like drowning or falling.

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