HIGHWAY ACCIDENT REPORT: TRANSPORT COMPANY OF TEXAS, TRACTOR-SEMITRAILER (TANK) COLLISION WITH BRIDGE COLUMN AND SUDDEN DISPERSAL OF ANHYDROUS AMMONIA CARGO, I-610 AT SOUTHWEST FREEWAY, HOUSTON, TEXAS, MAY 11, 1976

About 11:08 a.m., on May 11, 1976, a Transport Company of Texas tractor-semitrailer (tank) transporting 7,509 gallons of anhydrous ammonia struck and then penetrated a bridge rail on a ramp connecting I-610 with the Southwest Freeway (U.S. 59) in Houston, Texas. The tractor and trailer left the ramp, struck a support column of an adjacent overpass, and fell onto the Southwest Freeway, approximately 15 feet below. The anhydrous ammonia was released from the damaged tank semitrailer. Six persons died as a result of the accident, 78 persons were hospitalized, and approximately 100 other persons were treated for injuries. The National Transportation Safety Board determines that the probable cause of this accident was the excessive speed of the vehicle combined with the lateral surge of liquid in the partially loaded tank truck, which caused it to overturn. The cause of 5 of the 6 fatalities and all of the 178 injuries was the inhalation of anhydrous ammonia.

• Corporate Authors:

  National Transportation Safety Board

  Bureau of Accident Investigation, 800 Independence Avenue, SW
  Washington, DC  United States  20594
• Publication Date: 1977-4-14

Media Info

• Pagination: 23 p.

Subject/Index Terms

• TRT Terms: Ammonia; Bridge railings; Crash investigation; Crashes; Fatalities; Freight transportation; Hazardous materials; Highway bridges; Highway safety; Injuries; Motor vehicles; Ramps; Speed; Tank trucks; Tractor trailer combinations; Traffic crashes; Traffic speed; Trailers; Vapors
• Identifier Terms: Interstate Highway System
• Geographic Terms: Texas
• Old TRIS Terms: Cargo transportation
• Subject Areas: Freight Transportation; Highways; Motor Carriers; Safety and Human Factors;

Filing Info

• Accession Number: 00166366
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: NTSB-HAR-77-1
• Files: TRIS
• Created Date: Sep 20 1978 12:00AM