Abstract: Employee #1 and coworkers were running a completion string in an oil well and needed to pull the work string and run a different isolation packer on the production string of pipe. When they arrived to work, they found pressure at 350 psi on the well casing and 50 psi on the tubing. They decided to bleed the pressure off to the open mud tank close to the rig. They relieved the gas cap off the well head until they got oil back to the surface. They then pumped filtered brine back into the well to kill it so they could come out of the hole and run the production tubing and packer. While they were pumping the brine into the well and taking returns to the open mud pit, a natural gas cloud formed, which was ignited by an unknown source and exploded. Employees #1 through #4 sustained burns and were transported to the hospital. Employee #1 later died; Employees #2 through #4 were released after approximately two weeks for treatment on an outpatient basis. The source of ignition was most likely a gasoline engine on the trash pump that was pumping the brine through the filtration system.