Abstract: Employee #1 and coworkers, part of an oil well servicing crew, were cleaning an oil well using water gel and nitrogen under pressure. The nitrogen was being used to jet clean the well at 4000 psi. Employee #1 and a coworker were bringing the water gel line through a T on the reel unit. The high-pressure fluid pump was on idle speed, circulating fluid through the pump to the tank. Employee #1 was standing on the pump truck with one leg over the low-pressure fluid discharge line; the coworker, while checking the high pressure valve, opened it. High-pressure nitrogen entered the line and expanded, causing the discharge line to become a flying object due to the jet action. Employee #1 was struck and thrown about 15 ft from the pump truck, suffering head injuries. He died in the hospital two days later.