NTSB highlights ammonia hose threat

NTSB has asked PHMSA and FMCSA to issue a safety alert on the correct use of transfer hoses for anhydrous ammonia applications.The request comes as a result of NTSB's investigation of a fatal incident in July 2009, when a hose ruptured during delivery of ammonia from a tank truck to the Tanner Industries facility in Swansea, South Carolina. Almost 7,000 lb (3,125 kg) ammonia was released, which spread in a cloud across the neighbouring highway. One passing motorist was killed and several other people were injured.

NTSB has identified that the hose being used in the transfer was not rated for ammonia use. In all likelihood it had been switched at the yard of the tanker operator, Werner Transportation, for an LPG hose. The hose in question was chemically incompatible with ammonia, leading directly to the rupture. Oddly, the hose that ruptured was fitted with cast iron and steel couplings that would have been inappopriate for LPG use.

NTSB's recommendation to FMCSA reads:

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.

The summary of NTSB's investigation into the incident and its recommendation can be found here.