A senior
maintenance member of a two-man crew, and another employee were working from
an elevated work platform. The platform was mounted on the back of a
trailer, which was mounted to an asphalt tank. The employees had begun
bypassing the normal asphalt storage tank to prepare for its five-year
to seven-year cleaning. They placed a bypass valve in position to route
the asphalt from the permanent tank to the temporary, trailer-mounted
tank. Most of the asphalt piping was heated with a steam jacket
encircling the pipes. However, the piping that ran from the bypass valve
to the temporary tank was encircled with tubing that was heated by
steam. The employees complained that the steam tubing, also referred to
as steam tracing, was not wrapped tight enough, thereby preventing the
pipe from getting hot enough to turn the hardened asphalt back to its
liquid (melted) state. The employees then attempted to repair the
clogged pipe. As was reported to be the normal practice, they went to the end of the asphalt piping outlet and began heating
the last bend of the piping with a propane torch. The piping outlet was
located directly over the top of the manhole opening of the heated
asphalt tank. The tank was reported to be 300 degrees to 400 degrees
Fahrenheit, at that time. During the site visit, approximately five
hours later, the tank temperature gauge read approximately 260 degrees
Fahrenheit. After an undetermined amount of time that the employees were using the propane torch to heat the piping, an explosion
occurred in the asphalt tank. A witness described the explosion as a
flame which shot 30 feet above the manhole cover and quickly descended
back into the tank. This witness also stated that he could no longer
observe the employees standing on the platform. Employee #1 remained on
the platform and suffered asphalt burns and fractures to his face, where
an item impacted it during the explosion. Employee #2 fell from the
work platform, approximately 9 feet 5 inches to the concrete surface.
Employee #2 suffered asphalt burns to his body and face, in addition to a
hip fracture. A radio call for emergency response was broadcast
throughout the company. The company Emergency Response Team doused the
flames and provided initial first aid to Employees #1 and Employee #2.
Both employees were transported to the hospital.
Source:OSHA
Source:OSHA
