Roadway Transport Safety of Anhydrous Ammonia Tanks

Anhydrous Ammonia Tanks

Dee Jepsen, Associate Professor, Agricultural Safety and Health

As Anhydrous nurse tanks start rolling to the fields, roadway safety becomes a priority. This is a review of Ohio’s regulations to protect the transporter and the public.

  • Operator Age—Individuals transporting anhydrous ammonia must be 21 years old. (Ohio Administrative Code 4901:2-5-04,
  • Towing—It is highly recommended that the vehicle used to tow the nurse tank be at least equal in weight to the gross weight of the nurse tank. This will assist the operator in maintaining control minimizing the risk of a roadway incident. Roadway transport of an anhydrous ammonia nurse tank can include:     
    • Tractor, applicator and one nurse tank.    
    • Tractor and two nurse tanks. (Local supplier company policy may dictate that a customer may only tow one nurse tank.)     
  • Speed—The speed limit for anhydrous ammonia tanks traveling on the Ohio public roadways is 25 mph and a SMV emblem must be displayed.  (Ohio Administrative Code 4513.32,
  • Personal Protective Equipment—All vehicles transporting anhydrous ammonia shall carry a container of at least 5 gallons of water and be equipped with rubber gloves and either a full-face gas mask, a pair of tight-fitting goggles, or one full face shield. (Ohio Administrative Code 901:5-3-10,
  • Nurse Tank Leak During Transport—If a leak occurs in transportation equipment and it is not practical to stop the leak, the driver should move the vehicle to an isolated location away from populated communities or heavily traveled highways. (Ohio Administrative Code 901:5-3-10,

Prior to operating a nurse tank on a public roadway, carefully check:

  • Running Gear – Inspect the farm wagon frame tongue, reach poles, anchor devices, wheel bearings, knuckles, ball joints and pins for structural damage, cracks, excessive wear and adjustments.
  • Tires – Check for proper inflation. Check tire tread for cuts, badly worn spots, and signs of weathering. Assure that lug nuts are tight.
  • Lubrication – Steering knuckles, wheels, tongues, or other applicable farm wagon equipment should be lubricated at least once every year.
  • Hitch pin – a safety-type hitch pin with a standard safety chain attachment to the wagon or running gear. 
  • SMV emblem – With the mounted point up, place the sign 2-6 feet above the ground. Place the perpendicular plane to the direction of travel (+ or -) 10 degrees. Place the sign as near to rear center as possible.
  • Warning Lights – turn signals, flashing warning lights and a red brake light are recommended when towing an anhydrous ammonia tank wagon on public roadways. A standard seven terminal break-away connector plug should be used on the tank wagon to accommodate these lights.

There are legally required safety signs and labels to be on the nurse tanks. Federal Department of Transportation (DOT) requires Anhydrous to be marked consistently across all states. These markings include:

  • Nurse tanks must be labeled “ANHYDROUS AMMONIA” in 4-inch letters, on contrasting background, on the sides and rear of the tank.
  • The words “INHALATION HAZARD,” in association with the anhydrous ammonia label, in 3-inch lettering be placed on both sides of the tank.
  • A DOT approved “NON-FLAMMABLE GAS” placard with the numbers 1005 (identifying it as anhydrous ammonia) must be located on both sides and both ends of the tank.
  • The valves must be appropriately labeled by color or legend as vapor (Safety Yellow) or liquid (Omaha Orange). The letters of the legend must be at least 2 inches high on contrasting background and within 12 inches of the valves.

Graphics courtesy of Ohio Department of Agriculture: Summary of Nurse Tank and Tool Bar Requirements.
It is important to follow all rules of the supplier company. Additional training may be required by these companies to protect their liability when transporting and using their nurse tanks.

Additional information can be found on Ohioline with the “Safe Handling of Anhydrous Ammonia” fact sheet at:

Dee Jepsen, Associate Professor, can be reached at 614-292-6008 or jepsen.4@osu.eduThis column is provided by the OSU Extension Agricultural Safety and Health Team,