This case study examines a November 9, 2010,
explosion at an E.I. duPont de Nemours and Co.
Inc., Yerkes chemical plant in Buffalo, New York
when a contract welder and foreman were repairing
the agitator support atop an atmospheric storage
tank containing flammable vinyl fluoride. The
welder died instantly from blunt force trauma,
and the foreman received first-degree burns and
minor injuries. The explosion blew most of the
top off the tank. The top and agitator assembly
hung over the side of the tank supported only
by a 2-foot section of the top (cover photo). The
explosion caused minor overpressure damage in
the tank farm area and the adjacent production
building.
The U.S. Chemical Safety Board (CSB) determined
that flammable vinyl fluoride (VF) vapor
from interconnected, in-service process tanks flowed undetected into the tank and ignited
when the welder was repairing the agitator support assembly. In February 2010, the CSB
issued a “Hot Work Safety Bulletin” that summarized 11 similar fatal incidents. Like the
incidents described in the bulletin, this was another example of improperly monitored hot
work activities involving flammable conditions inside a container.