Aerial image of crash scene showing final rest positions of truck-tractor cargo tank semitrailer combination and utility trailer

​​Aerial image of crash scene showing final rest positions of truck-tractor cargo tank semitrailer combination and utility trailer. [2] (Source: Illinois State Police; annotated by NTSB) 

Cargo Tank Combination Vehicle Roadway Departure, Rollover, and Release of Anhydrous Ammonia

What Happened

​On September 29, 2023, about 8:41 p.m. central daylight time, a minivan began passing a truck-tractor cargo tank combination vehicle (combination vehicle) carrying anhydrous ammonia while traveling west on two-lane United States Highway 40 (US-40) near Teutopolis, Effingham County, Illinois. As the minivan, operated by a 17-year-old driver, was still in the process of passing, in the no passing zone, an oncoming vehicle approached. To accommodate the passing minivan and prevent a head-on collision in the opposite lane, the combination vehicle driver steered right. The combination vehicle departed the roadway, entered a drainage channel, overturned, rolled onto its right side, and slid forward until the front of the cargo tank struck a utility trailer parked in a residential yard. The collision with the trailer punctured the cargo tank, causing the release of anhydrous ammonia. The release caused five fatalities among nearby residents and vehicle occupants, serious injuries to nine, and minor injuries to four.

What We Found

​We determined that the probable cause of the Teutopolis, Illinois, roadway departure and overturning of the combination vehicle was the unsafe passing maneuver by a teen driver that caused the combination vehicle driver to initiate an evasive action that resulted in loss of vehicle control and rollover. Contributing to the severity of the crash was the subsequent impact of the overturned cargo tank with a parked utility trailer that resulted in the release of anhydrous ammonia.​

Lessons Learned

​Risky Behaviors Among Teen Drivers. This crash demonstrates the ongoing challenges associated with teen driver inexperience, particularly in complex traffic situations requiring quick judgment. Even drivers who have completed comprehensive graduated driver licensing programs may lack the experience necessary to accurately assess distances and timing during high-risk maneuvers such as passing, especially in dark conditions. Educational institutions, driving schools, and parents should continue to emphasize the importance of conservative decision-making and the recognition that inexperience can lead to poor judgment regardless of formal training completion.

Safe Transportation and Incident Management of Anhydrous Ammonia. This crash also serves as a reminder that anhydrous ammonia, while classified as a Division 2.2 non-flammable, nonpoisonous gas, poses significant risks to public health when released. Emergency responders should prepare and use appropriate PPE and decontamination procedures when responding to incidents involving anhydrous ammonia, and they should verify the appropriate mitigation and protection procedures with the shipper of the hazardous material. The toxic and corrosive nature of this substance requires Level A PPE for safe entry into affected areas, and proper staging of decontamination stations is essential to prevent contamination of transport vehicles and medical facilities.

Video

Watch the first media briefing on Oct. 1 at NTSB YouTube ​below
https://www.youtube.com/watch?v=AQ38OxtoANE
NTSB B-Roll: Tanker Truck Rollover in Teutopolis, IL
https://www.youtube.com/watch?v=3OBB3N7yZPU
 
 
 
 

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