Modeling Dispersion from Toxic Gas Released after a Train Collision in Graniteville, SC



The Savannah River National Laboratory (SRNL) Weather Information and Display System was used to provide meteorological and atmospheric modeling/consequence assessment support to state and local agencies after the collision of two Norfolk Southern freight trains on the morning of January 6, 2005. This collision resulted in the release of several toxic chemicals to the environment, including chlorine. The dense and highly toxic cloud of chlorine gas that formed in the vicinity of the accident was responsible for 9 fatalities and caused injuries to more than 500 others. Transport model results depicting the forecast path of the ongoing release were made available to emergency managers in the county’s Unified Command Center shortly after SRNL received a request for assistance. Support continued over the ensuing 2 days of the active response. The SRNL also provided weather briefings and transport/consequence assessment model results to responders from the South Carolina Department of Health and Environmental Control, the Savannah River Site (SRS) Emergency Operations Center, Department of Energy headquarters, and hazard material teams dispatched from the SRS. Operational model-generated forecast winds used in consequence assessments conducted during the incident were provided at 2-km horizontal grid spacing during the accident response.  High-resolution Regional Atmospheric Modeling System (RAMS, version 4.3.0) simulation was later performed to examine potential influences of local topography on plume migration in greater detail. The detailed RAMS simulation was used to determine meteorology using multiple grids with an innermost grid spacing of 125 m.  Results from the two simulations are shown to generally agree with meteorological observations at the time; consequently, local topography did not significantly affect wind in the area. Use of a dense gas dispersion model to simulate localized plume behavior using the higher-resolution winds indicated agreement with fatalities in the immediate area and visible damage to vegetation.



On January 6, 2005, at  2:40 a.m., a Norfolk Southern freight train traveling northbound through the town of Graniteville, SC, collided with a second freight train parked on an industrial rail spur, resulting in the rupture of rail cars transporting liquefied chlorine and other industrial chemicals. The subsequent rapid discharge of  70 t of chlorine quickly produced a dense airborne cloud of toxic gas and aerosols that spread throughout property occupied by a textile mill and into adjacent areas of town, resulting in the deaths of 9 individuals, mainly mill workers, and injuries to  500 others.1 Graniteville is located in west-central South Carolina a few kilometers west of Aiken, SC, and 20 km north of the Department of Energy’s Savannah River Site (SRS).


The threat of a rupture to additional tankers of chlorine that were damaged in the accident resulted in closure of businesses and the relocation of  5000 residents for  9 days, as crews worked to dispose of the remaining inventories.  Hundreds of emergency workers from local volunteer fire departments, Aiken County sheriff and emergency management offices, the SRS, and state and federal agencies responded to the event. As part of a mutual aid agreement with Aiken County, the Atmospheric Technologies Group (ATG) of the Savannah River National Laboratory (SRNL) at SRS supported decision-makers in the county’s Joint Operation Center with hazard consequence modeling and meteorological assessments over the 2-day period of active response.


The SRS is an 800-km2 (310-mi2) nuclear facility owned by the U.S. Department of Energy and operated by the Washington Savannah River Company. The SRS is located in Western South Carolina,  20 km south of Aiken, bordered on the west by the Savannah River (Figure 1). Established in 1950, the SRS produced radionuclides in support of the nation’s defense and currently operates programs supporting nuclear nonproliferation, disposition of radiological and chemical waste, and environmental remediation.

Customer comments

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