A train carrying hazardous material was deliberately derailed in a residential/commercial area in the southeastern U.S. Three train cars contained chlorine. One chlorine rail car containing 90 tons of product released approximately 40 tons of chlorine, retaining the rest (50 tons of product) due to auto- refrigeration. The release of chlorine vapor migrated from the derailment site, over and through an adjacent working factory and then over a large number of commercial and residential areas in the city before it dissipated. Because chlorine gas is denser than air, some of the chlorine gas settled into low- lying areas and dissolved into the waters of a nearby creek located adjacent to the factory. A fish kill was subsequently observed due to this release.
The other chlorine rail cars were derailed and the integrity of these cars was initially unknown. Additionally, approximately 3,000 gallons of diesel fuel were discharged from one of the wrecked locomotives.
Potential threats to public health and the environment posed by this incident included: actual and potential exposure of humans and animals to chlorine vapors in the air; potential dermal exposure to chlorine and hydrochloric acid near the derailment scene; actual and potential chlorine exposure of aquatic life in nearby surface water bodies; and a threat of discharge of oil into a waterway. In addition, the other cars containing chlorine presented a serious threat of potential release into the environment.
The derailment and release killed several people, injured approximately 250, and required the evacuation of about 5,400 people within a one-mile radius of the incident. The response phases spanned a period of two weeks.