PHOENIX -- A pool pump that combusted is being blamed for triggering last month's large fire in a midtown Phoenix industrial area.
Phoenix Fire Department investigators say some employees at Fuels LLC were pumping used motor oil from one container to another on the morning of April 22.
The hose detached, spilling fluid onto the pump's gas-powered motor. Investigators say the heat of the motor most likely caused the oil to combust.
The Arizona Republic reports two employees remain hospitalized with severe burns.
Fire Marshal Jack Ballentine says investigators determined the pump was the kind used for pools and was inappropriate for the combustible material the company was handling.
The blaze produced flames 110 feet high and smoke so dense it blotted out the sun in downtown Phoenix.