U.S. Department of Labor
Process: Housekeeping Safety
A painter was working aboard a fishing vessel, preparing a crab hold for painting. After sandblasting the hold, he sprayed approximately 3 - 5 gallons of acetone on all surfaces of the confined space. This was done to settle the dust created from the sandblasting operation, as well as to help dry its surface more quickly. The worker then placed a fan at the opening of the hold to blow air into the space. The fan, which had no exhaust duct affixed, ran for about one hour, at which point the worker entered the space to begin vacuuming up the sandblasted material.
As the worker turned on the shop vacuum, the acetone vapors in the space ignited, resulting in a fire and ultimately an explosion. The worker, who was wearing polyester coveralls, received third-degree burns over 90 percent of his body and later died.
Analysis and Preventive Measures
No matter what type of media is used, sandblasting is a messy job. However, there are safer methods than the spraying of acetone to contain the dust created. The employer should have ensured that the appropriate exhaust ventilation was used while the sandblasting was taking place.
Atmospheric monitoring by a competent person was necessary to determine if a toxic and/or explosive atmosphere existed (29 CFR 1915.13(b)(2)). This would have indicated that further ventilation was necessary before the worker could enter the space, or that respiratory protection was necessary to eliminate exposure to toxic vapors. Also, only "intrinsically safe" or "explosion-proof type" motors are permitted in spaces where highly toxic, flammable and explosive solvents are present and contain a LEL greater than 10% (29 CFR 1915.13(b)(9) and 1915.36(a)(4)). Any fans used in such environments must have non-sparking blades, and portable air ducts made up of non-sparking materials (29 CFR 1915.13(b)(12)).