Abstract: At approximately 7 p.m. on July 7, 2001, two maintenance technicians, Employee #1 and Employee #2, at Maxim Integrated Products determined the potential source of an unusual odor in AMAT areas Nos. 3 and 4, and donned airline respirators as a precautionary measure before staring work to isolate an overheated air pump. Monitoring for hydrogen bromide (HBr) and chlorine via a gas detection system was set up in advance of the maintenance activity. In disconnecting the exhaust discharge side, Employee #1 was exposed when a small isolated cloud of HBr was released. The monitoring system did not detect any chlorine or HBr and no alarms were activated. Employee #1 and Employee #2 reported the incident to the plant's emergency response team. As a precautionary measure the emergency response team decided to evacuate the area on an informal basis. There were 15 other employees working in the general area. The evacuation was done verbally only, which resulted in confusion about the seriousness of the incident. Furthermore, Maxim's emergency response team called the public emergency medical services and requested a medical evaluation of the affected employees. Responding to the scene, the fire department hazmat team arrived and assumed on-scene incident command taking all 17 potentially-affected employees to area emergency rooms. Employee #1 and Employee #2 experienced only mild respiratory irritation symptoms. Other employees in the area experienced mild irritation and headaches. All 17 employees were returned to work by the end of the shift. No one was admitted to the hospital.