Abstract: On January 21, 2003, Employees #1 and three coworkers were working to increase the flow rate of ozone to a quick dump rinse station on an automated wet bench. The wet bench had a local exhaust ventilation plenum engineering control for normal operation. One coworker was observing the remedial activity and another coworker had left the room. Either Employee #1 or the coworker assisting Employee #1 reached inside the plenum through the open plenum door to move a line to obtain a better view. A previously disconnected ozone supply line shifted, pointed directly into the face of Employee #1 and delivered the full flow of ozone onto his face. Employee #1 and the coworker both suffered respiratory irritation and Employee #1 was hospitalized. The original narrative did not specify the medical treatment for the coworker.