Abstract: At approximately 3:45 p.m. on August 1, 2003, Employees #1, a loader operator, and #2, a laborer, were pushing municipal waste on the tipping floor of the Municipality of Anchorage Solid Waste Transfer Facility. While they were working, a gaseous chemical agent was released in the area of the loader. If the contaminant possessed a detectable odor, the odor was indistinct, perhaps due to masking by odors associated with municipal solid waste material. Employees #1 and #2, and several members of the general public, after being exposed to the invisible gaseous contaminant, exhibited symptoms of physical distress. The symptoms included breathing difficulty, a sense of heaviness or tightness in the chest area, watering of the eyes, disorientation, and nasal discharge. Each person, interviewed in the aftermath of the incident, indicated that he or she was experiencing a persistent sensation of thirst. Employees #1 and #2 were apparently free of physical distress by 8:00 p.m. on the night of the incident. None of the affected employees required overnight hospitalization.