Abstract: At approximately 9:03 a.m. on February 13, 1989, an anhydrous ammonia (NH3) leak due to a faulty snap valve occurred at Oelwein Soil Service, Oelwein, IA. Approximately 25,000 gallons of NH3 were in the stationary tank. Employee #1 called the Oelwein Fire Department, which dispatched Employees #2, #3, #4, #5, and #6 (volunteer fire fighters) to the scene. The Oelwein Fire Department called Hazelton Fire Department, which sent Employees #7 and #8 (fire fighters). The Oelwein Fire Department acted as coordinator. Oelwein Fire Department volunteers, wearing SCBA and bunker gear, made attempts to close the valve, which was done at approximately 12:47 p.m. Employee #1, who was trying to prime a pump and was splashed in the eyes by NH3-containing water from the ground; Employees #2 through #6 (firefighters), who sustained NH3 burns under their bunker gear in the belt areas of the groin and legs; Employees #7 and #8, who sustained burns; Employee #9, who was directing traffic and was briefly exposed when the wind changed; and Employee #10, who had brought a 3 in. pump to clean up water on the ground as directed by DNR and received arm blisters, went to Mercy Hospital in Oelwein, from which they were released by February 14, 1989.