Swansea, South Carolina
July 15, 2009
NTSB Number: HAZ-12-01-SUM
NTIS Number: PB2012-917002
Adopted April 12, 2012
On July 15, 2009, about 8:00 a.m., a cargo transfer hose ruptured shortly after transfer of anhydrous ammonia began from a Werner Transportation Services, Inc. cargo tank truck to a storage tank at the Tanner Industries, Inc. facility in Swansea, South Carolina. A white cloud of anhydrous ammonia, a toxic-by-inhalation gas, moved from the parking lot of the facility across U.S. Highway 321 to a largely wooded area, where it eventually dissipated. About the same time, a motorist traveling north on the highway drove into the ammonia cloud, apparently tried to get away from the cloud, then got out of her car and died of ammonia poisoning. Seven people went to the Lexington Medical Center emergency department complaining of respiratory problems and dizziness; all seven patients were treated and released the same day. The anhydrous ammonia cloud caused temporary discoloration of vegetation in the area, including the leaves on the trees. Residents in the area sheltered in place, and U.S. Highway 321 was closed until about 2:00 p.m. on the day of the accident. The Lexington County Fire Service arrived on scene about 8:07 a.m. Property damage and losses were limited to the ruptured hose and about 6,895 pounds of the anhydrous ammonia that was released.
The National Transportation Safety Board determines that the probable cause of the accident was Werner Transportation Services, Inc.'s use of a cargo hose assembly that was not chemically compatible with anhydrous ammonia. Contributing to the accident was the lack of explicit requirements by the Pipeline and Hazardous Materials Safety Administration that the motor carrier and the facility carrier verify that the cargo hose assembly is chemically compatible with the product to be transferred before transfer operations begin.
The following safety issues were identified in this accident:
As a result of its investigation of this accident, the National Transportation Safety Board makes safety recommendations to the Federal Motor Carrier Safety Administration and the Pipeline and Hazardous Materials Safety Administration.
As a result of its investigation of this accident, the National Transportation Safety Board makes the following safety recommendations:
To the Federal Motor Carrier Safety Administration:
With the Pipeline and Hazardous Materials Safety Administration, jointly issue a safety advisory bulletin to inform cargo tank motor vehicle owners and operators, registered inspectors of these vehicles, and transfer facility operators about the circumstances of this accident and actions needed to prevent the occurrence of a similar accident. (H-12-1)
To the Pipeline and Hazardous Materials Safety Administration:
With the Federal Motor Carrier Safety Administration, jointly issue a safety advisory bulletin to inform cargo tank motor vehicle owners and operators, registered inspectors of these vehicles, and transfer facility operators about the circumstances of this accident and actions needed to prevent the occurrence of a similar accident. (H-12-2)
Require cargo tank motor vehicle carriers and transfer facilities to verify (1) that cargo transfer hose assemblies, whether carried on the vehicle or provided by the facility, are chemically compatible with the hazardous material to be transferred and (2) that drivers verify hoses are marked as compatible with the material to be transferred before either loading or unloading operations begin. (H-12-3)
Amend the provisions of Title 49 Code of Federal Regulations 173.315(n)(2) to require that passive emergency shutdown control systems for highway cargo tanks activate in the event of a partial or complete failure of a cargo hose assembly. (H-12-4)
Publish and disseminate a formal interpretation of Title 49 Code of Federal Regulations 180.416(d) that includes the criteria used to determine when a cargo transfer hose assembly is "in service." (H-12-5)
Issue guidance to motor carriers and registered inspectors that clarifies the testing and the recordkeeping requirements of Title 49 Code of Federal Regulations 180.407 for cargo hose assemblies and cargo tanks that are used to transport liquefied compressed gases to ensure that all hose assemblies are tested for leaks on an annual basis. (H-12-6)