About 11:50 a.m. central daylight time on April 15, 2003, a nonspecification cargo tank used by River Valley Cooperative (River Valley) exclusively for agricultural purposes as a nurse tank split open after being filled with anhydrous ammonia at River Valley's nurse tank filling facility near Calamus, Iowa. About 1,300 gallons of the poisonous and corrosive gas escaped, seriously injuring two nurse tank loaders, one of whom died from his injuries 9 days after the accident. Equipment repair and replacement costs associated with the accident totaled about $3,100.
The National Transportation Safety Board determines that the probable cause of the sudden failure of the nurse tank at the anhydrous ammonia filling facility near Calamus, Iowa, on April 15, 2003, was inadequate welding and insufficient radiographic inspection during the tank's manufacture and lack of periodic testing during its service life.
As a result of its investigation of the accident, the Safety Board identified two major safety issues:
- The adequacy of standards for initial qualification and periodic testing of nurse tanks.
- The adequacy of River Valley's emergency procedures for anhydrous ammonia nurse tank loaders.
As a result of its investigation of this accident, the Safety Board makes safety recommendations to the Research and Special Programs Administration and River Valley.
As a result of its investigation of the April 15, 2003, hazardous materials accident near Calamus, Iowa, the National Transportation Safety Board makes the following safety recommendations:
To the Research and Special Programs Administration:
Require periodic nondestructive testing to be conducted on nurse tanks to identify material flaws that could develop and grow during a tank's service and result in a tank failure. (H-04-23)
To the River Valley Cooperative:
Review manufacturers' material safety data sheets for anhydrous ammonia, the National Institute for Occupational Safety and Health's HAZOP of Anhydrous Ammonia Use in Agriculture, and the Emergency Response Guidebook and establish written emergency procedures for employees to follow when an anhydrous ammonia release poses an inhalation hazard. (H-04-24)