Safety advisory on older nurse tanks

The Federal Motor Carrier Safety Administration (FMCSA) and the Pipeline and Hazardous Materials Safety Administration (PHMSA) have issued a safety advisory on the possibility of a catastrophic failure of “nurse tanks.” This specifically applies to nurse tanks manufactured between January 1, 2007, and December 31, 2011, by the Fremont, Ohio-based plant of American Welding and Tank (AWT).

What you need to know

Nurse tanks are heavy duty trailers used to transport various types of hazardous materials and liquids.

During the summer of 2023, a 2009 AWT nurse tank carrying anhydrous ammonia had a catastrophic failure, releasing all of the product and “rocketing” the tank shell over 300 feet. This incident indicates potential continued problems with ATW nurse tanks.

Radiographic testing proved that seven of eight ATW nurse tanks manufactured between 2008-2012 had extreme stress corrosion cracking, porosity, and inclusions/welds at the points where the tanks were joined. All but the 2012 models failed the tests. As a result, the 2007-2011 series of tanks were voluntarily placed out-of-service by the owner.

What you should do

The FMCSA and PHMSA strongly recommend owners of these nurse tanks (ATW models from 2007-2011) to conduct:

• Voluntary periodic inspection and testing (49 CFR 173.315(m)(2)(i)),
• Thickness testing (49 CFR 173.315(m)(2)(ii)), and
• Pressure testing (49 CFR 173.315(m)(2)(iii)).

Owners of the affected nurse tanks who cannot perform voluntary pressure testing should conduct radiographic or ultrasonic testing. FMCSA and PHMSA recommend conducting inspections and tests consistent with 49 CFR 173.315(m)(2)(i) once every five years.

Please contact Paul Bomgardner, Chief, FMCSA Hazardous Materials Division, at 202-493-0027, or by email at paul.bomgardner@dot.gov for more information.