Abstract: A 4-stage nitrogen/hydraulic accumulator was being tested during final inspection. The accumulators were charged (fluid pumped into four tanks) with approximately 46 gal of Mobile DTE 25 hydraulic oil and the outlet/inlet valve was closed to verify that an accumulated charge of approximately 5,000 psi was held. The test required that the blow down test (sudden and complete release of fluid) be completed to determine if accumulators would evacuate within the given tolerance of approximately 12 seconds. The test conductor attached a 1 1/2 in. 25 ft long high pressure flexline to the outlet valve, had four workers hold the open end of the hose down into the open bung hole of a 55-gal drum, and opened the valve. The fluid struck the bottom of the barrel and misted up through the bung hole into the face of one holder, who let go to cover his eyes. The ensuing whipping action caused the brass end of the hose to strike Employees #1, #2, and #3, causing fractures and skin abrasions. They were hospitalized.