Abstract: At approximately 6 p.m. on October 10, 2009, Employee #1 and two coworkers, employees at the Banks Pumping Plant, Delta Field Division facility, CA Department of Water Resources, Byron, CA, were inspecting the plant during a planned power outage. They were inspecting 11 accumulator units for any evidence of hydraulic oil overflow from the oil reservoir at each unit. At the Unit 6 Accumulator, they discovered an oil spill around the unit's oil reservoir. They contained the spill with available materials and within the limits of their training, using flashlights since the lighting was off. Employee #1 asserted that an oil mist existed in the Unit 6 area after the spill, lasting until power was restored in the plant at approximately 7:22 p.m. Employer #1 felt a chest condition but did not report the condition to the Safety Officer until 4:00 a.m. on October 11, 2009. Employee #1 was transported to Tracy Sutter Hospital, hospitalized, and treated for chest pains.