A 52-year-old male was fatally injured when he was burned due to a flash fire inside a 23’ long x 6’ diameter stainless steel tank. The company was contracted to restore a stainless steel tank so that it could be returned to the dairy process as a Sugar Tank. At the time of the incident, an employee was spray applying a food-grade lining system (Carboline Plasite 7133) inside the tank.
Employees sandblasted the inside of the tank two days prior to the incident and “spot blasted” the interior of the tank the morning of the incident. Employees mixed two parts of the lining system (Plasite 7133 Part A and Plasite 7133 Part B; both category 2 flammable liquids) in a bucket then poured the mixture in the “spray pot” for application.
Employees wore supplied-air respirators when applying the Plasite 7133 inside tanks and negative pressure/exhaust ventilation was provided by a 12″ diameter flexible duct positioned at the opening of the tank. The duct traveled along the outside length of the tank, then up & through a wall opening where it was attached to an in-line duct booster fan and then to a pneumatic-powered Coppus fan. It was determined that the entry into the tank was made under the company’s confined space program and non-entry rescue was implemented at the site. A gas monitor was onsite and used to conduct periodic monitoring; continuous monitoring during permit-required confined space work was not done.
The occurrence of a flash fire indicated that a vapor-to-air concentration at or above 10% of the chemical mixture’s LEL found an ignition source. Because the atmosphere inside the tank was at or above 10% of the LEL, the employee was working in an IDLH atmosphere. The investigation revealed that the victim took a non-intrinsically safe light into the tank while he was painting and the heat from the light ignited the flammable vapors resulting in the flash fire. Management stated that an intrinsically safe light was onsite at the time of the incident but, for unknown reasons, the victim grabbed the wrong one.
Citation(s) as Originally Issued:
