Abstract: On September 19, 2011, Employee #1, a second shift production operator, was transferring ammonium fluoride to the buffered hydrofluoric acid storage tank. This task involved inserting a siphon into a 55-gallon drum of ammonium fluoride and activating the pump. Both the 55-gallon drum and the pump were located inside protective enclosures. The drum enclosure was fitted with strip curtains on the front. As Employee #1 turned on the pump, he noticed an ammonium fluoride leak coming from the hose fitting on top of the siphon. He reached into the enclosure and attempted to tighten the fitting. This action caused the leak to increase and liquid sprayed through the open curtain. The ammonium fluoride liquid hit Employee #1's face shield and arm, and a small amount sprayed onto his scalp. Employee #1 alerted his supervisor about the exposure and immediately went to a shower. He showered for approximately 20 minutes. Coworkers then treated his scalp with calcium gluconate gel and called emergency medical services. Paramedics arrived, and they had Employee #1 shower for an additional 20 minutes. Employee #1 was then transported to the emergency room. He was treated with calcium gluconate administered intravenously and hospitalized until the next morning. Employee #1 did not experience skin burns, noticeable pain, or any other symptoms, as a result of the exposure.