Introduction

More anhydrous ammonia is used as fertilizer in 

North Dakota than any other nitrogen fertilizer 

source. Anhydrous ammonia is classifi ed as 

a hazardous substance. Most accidents with 

anhydrous ammonia are due to uncontrolled 

releases. Few problems occur when the 

ammonia is being handled and applied as 

intended. Most uncontrolled releases are due 

to improper procedures, careless or untrained 

workers, or faulty equipment. Protective 

equipment is required by law to be available 

where anhydrous ammonia is handled or 

applied. Wearing protective equipment greatly 

reduces the chance of injury from an ammonia 

release. Countless tons of anhydrous ammonia 

are applied every crop year without problems; 

safe procedures and good-quality equipment do 

work. 

Anhydrous ammonia has the potential to 

be one of the most dangerous chemicals used 

in agriculture today. It is used and stored under 

high pressures, which requires specially designed 

and well-maintained equipment. Those who 

work with anhydrous ammonia must be trained 

to follow exact procedures in handling it. 

Anhydrous Ammonia: Managing The Risks

John Nowatzki

Ag Machine Systems Specialist

AE-1149 (Revised)

North Dakota State University

Reviewed and reprinted May 2011

Chemistry of 

Anhydrous Ammonia

Ammonia is a chemical compound used as a fertilizer 

because it is rich in nitrogen. Its chemical formula 

is NH3, which means that it consists of one atom of 

nitrogen and three atoms of hydrogen per molecule. 

Because the atomic weights of nitrogen and hydrogen 

are not the same, the weight ratio is 82.5 percent 

nitrogen to 17.5 percent hydrogen. Anhydrous means 

the ammonia is without water. This distinguishes it 

from ammonia/water solutions.

Characteristics of 

Anhydrous Ammonia

Odor

Anhydrous ammonia is a clear, colorless gas at 

standard temperature and pressure conditions and has 

a very characteristic odor. The odor is the strongest 

safety feature of the product. At a concentration of

only 50 parts per million (ppm), one sniff tells what is 

in the air. Normally, the odor will drive a person away 

from the area. A concentration of more than 5,000 

ppm will disable a person so that escape is impossible 

and suffocation results. 

Pressure for Storage

Anhydrous ammonia is a liquid when compressed or 

cooled. It is stored under pressure to prevent vaporization so a large volume can be available for use. One 

cubic foot of anhydrous ammonia in a liquid state produces 855 cubic feet of ammonia gas. Retail storage 

tanks and nurse tanks for anhydrous ammonia are built 

to withstand internal pressures of at least 250 pounds 

per square inch (psi). Terminal storage tanks refrigerate ammonia to minus 28 degrees Fahrenheit. At this 

temperature, the storage pressure is less than 1 psi. 
2

Temperature/Pressure 

Relationships

When anhydrous ammonia is released from 

compression in a storage tank (200 psi) to the 

atmosphere (0 psi), the temperature drops from 100 

F to minus 28 F. At this temperature, ammonia freezeburns human skin on contact. Clothing actually is 

frozen to the skin. Since anhydrous ammonia is stored 

under high pressure, a sudden rupture can shoot 

ammonia 10 to 20 feet from the point of release. 

all ammonia and its salts. Remember, never weld on 

a closed container of any kind; all containers must 

be completely cleaned and vented. Apply heat only 

to open containers, including all piping. Welding 

should be done only by a welding fi rm with a type 

“R” certifi cation in compliance with the North Dakota 

Century Code.

Anhydrous

Anhydrous ammonia contains no water. Anhydrous 

is the Greek word for “without water.” Anhydrous 

ammonia has a very strong affi nity for water. It 

requires large quantities of water to neutralize its 

caustic effects on moist areas of the body. When 

anhydrous ammonia contacts water, it forms 

ammonium hydroxide. Living tissue is dehydrated 

quickly and the cells destroyed on contact. Anhydrous 

ammonia attacks any moist part of the body: eyes, 

ears, nose, throat, bronchia, lungs, any moist skin. Any 

tissue containing moisture is chemically burned.

Caustic Nature

When anhydrous ammonia comes in contact with 

water, it forms an alkali that chemically burns animal 

tissue. The chemical burns into the body tissue unless 

it is diluted by large quantities of water. Anhydrous 

ammonia is extremely destructive to animal tissue. 

Skin is reduced to a sticky, gooey substance as the 

chemical burn progresses. Skin that is chemically 

burned by the ammonia actually is killed and is not 

capable of healing or replacing itself. Damaged 

tissue must be removed surgically so that healing can 

proceed. The results often are disfi guring. 

Table 1. Exposure Levels and The Human Body.

 Exposure (ppm) Effect on the Body Permissible Exposure

 50 ppm Detectable by most people No injury from prolonged,

 or repeated exposure

 134 ppm Irritation of nose and throat Eight hours maximum exposure

 700 ppm Coughing, severe eye irritation, One hour maximum exposure

 may lead to loss of sight

 1,700 ppm Serious lung damage, No exposure permissible

 death unless treated 

 2,000 ppm Skin blisters and burns within seconds No exposure permissible

 5,000 ppm Suffocation within minutes No exposure permissible

Table 2. Temperature and 

Pressure Relationships.

 Degrees F Pressure (psi)

 -28 F 0 psi

 0 F 16 psi

 32 F 48 psi

 60 F 93 psi

 100 F 200 psi

Flammability

Anhydrous ammonia is generally not considered 

to be a fl ammable hazardous product because its 

temperature of ignition is greater than 1,560 degrees 

F and the ammonia/air mixture must be 16 percent to 

25 percent ammonia vapor for ignition. 

In spite of the diffi culty of igniting such a mixture, 

never weld on any container or piping that has not 

been completely decontaminated and cleaned of 
3

Types of Exposure

Skin

Anhydrous ammonia causes freezing and chemical 

burn wherever skin and clothing are moist. The 

subzero temperature of escaping anhydrous ammonia 

freezes clothing to the body. Do not attempt to 

remove any clothing that is frozen to the skin. It must 

be thawed loose fi rst or skin tissue may be pulled from 

the victim. 

The caustic nature of anhydrous ammonia causes 

skin and tissue burns similar to burns from heat. Do 

not apply salves, creams or ointments of any kind to 

the injury. The caustic burning can be stopped only by 

dilution with large quantities of water.

Eyes

Eyes are continually bathed in moisture. Anhydrous 

ammonia will seek this moisture. The burns will result 

in damage to the eyes, such as cataracts, glaucoma 

and possibly some permanent vision loss and 

disfi gurement. 

If eyes have been exposed to anhydrous ammonia, 

they must be fl ushed with water immediately and 

continually and the victim must be taken to a doctor 

immediately. Everyone who works with anhydrous 

ammonia should carry a 6- or 8-ounce squeeze bottle 

of fresh water on their person at all times. This small 

amount of water will last only long enough for the 

worker to get to a larger quantity of water, but it may 

make the difference between blindness and sight. 

Initially, forcing the victim’s eyelids open after the 

exposure may be necessary. The ammonia trapped 

under the eyelids must be fl ushed out with water or it 

will continue to burn the eye and related tissues.

Lungs

At low concentrations, the odor of anhydrous 

ammonia usually will drive the unprotected 

worker away from the scene. At a higher level of 

concentration (see Table 2), the worker may not 

escape without inhaling a dangerous dose. The 

entire respiratory system is very moist, so anhydrous 

ammonia will be attracted naturally to that part of 

the body. When a concentrated level of anhydrous 

ammonia is inhaled, it will burn the respiratory system 

quickly. The victim may hurt too much to breathe. The 

respiratory system essentially may be paralyzed due to 

the pain. 

First-response rescue workers may not be able to 

treat a serious inhalation exposure. Medical technicians 

may be able to administer oxygen to aid breathing 

after their arrival on the scene. Maintaining adequate 

respiration for the victim until delivery to a medical 

facility may be diffi cult. 

Respiratory protection is extremely important, but 

also limited in what equipment is available. A twocartridge respirator is effective only for exposure levels 

of less than 300 ppm. Canister type respirators may be 

effective for longer periods at higher concentrations, 

but without skin protection, walking through an 

ammonia cloud is generally not advisable. A selfcontained breathing apparatus (SCBA), which supplies 

the air to be breathed, and a sealed, protective 

HazMat suit are required for working in a cloud of 

escaping anhydrous ammonia. Anything less will not 

suffi ciently protect a person in this situation.

First Aid Calls For Water + 

Water + Water

Start fi rst aid treatment immediately when someone is 

exposed to anhydrous ammonia. The chemical burning 

starts instantly and the injury becomes worse as time 

passes. Treatment consists of fl ushing the affected 

body area(s) with large quantities of water. 

One short fl ushing is not suffi cient. Maintain a 

steady fl ow of water over the affected area(s) until 

the victim is delivered to medical help. The water 

provided with each nurse tank or other container 

will not be enough. Five gallons fl owing in a pencilsized stream will last approximately seven minutes. 

Additional water should be carried on every tractor 

used in fi eld applications and in every fi eld support 

motor vehicle. Collect as much water as possible and 

continue fl ushing while arrangements are being made 

to transport the victim to a medical facility. Do not 

reuse the water; it will not provide relief, having already 

absorbed anhydrous ammonia.
4

Transport To Medical Facility

Make arrangements to transport the victim to a doctor 

or hospital immediately after exposure. First aid can be 

given while transport arrangements are being made, 

but get the victim to medical care as soon as possible. 

Notify the hospital that the victim is being transported. 

First aid fl ushing should be continued while in 

transport.

Uncontrolled Releases

Clouds of anhydrous ammonia are subject to the 

unpredictability of air movement; they will change 

direction as quickly as the breeze. Clouds of ammonia 

may be nearly invisible in some atmospheric 

conditions, but they appear as white clouds when the 

atmosphere is damp. Rain will absorb the ammonia 

and remove it from the air. 

Anhydrous ammonia is heavier than air and will 

settle in the low areas of the surrounding landscape, 

such as road ditches, sloughs and valleys. People in 

threatened areas must be warned of the release and 

advised to leave the area until the release has been 

controlled and the area is considered safe for reentry. These decisions should be made by emergency 

personnel, such as a local fi re department. Animals 

and livestock should be removed from the threatened 

area after people have been taken care of fi rst. Most 

animals will do their best to leave the area long before 

ammonia concentrations become strong enough to 

cause them much discomfort.

Protective Equipment 

for Anhydrous Ammonia

Due to the seriousness of exposure to 

anhydrous ammonia, personal protective 

equipment must be well-maintained. This 

includes unvented goggles; rubber gloves; 

respirator; heavy-duty, long-sleeved shirt; and 

long pants.

The goggles and gloves are to be kept in a safety 

equipment container mounted on each nurse tank 

and be accessible from the ground. Having another 

set readily available on the tractor is an excellent idea. 

Suitable gloves are made of rubber and are impervious 

to ammonia, and have long cuffs that should be 

turned back to prevent drips from running down the 

arm when hands are elevated. The fi t should be loose 

enough for easy removal but snug enough for good 

protection. 

Figure 1. Emergency Equipment 

(for Escape Only) 

Gas Mask

Protective Suits

or Slickers

Rubber Boots
5

Goggles must be unvented to keep the anhydrous 

ammonia away from the eyes. Only the un-vented type 

of goggles will minimize ammonia exposure to the 

eyes. Pesticide-type vented goggles are not suitable 

because ammonia can pass through the indirect vents. 

Open-vented shop goggles never should be used. 

A respirator equipped with anhydrous ammonia 

cartridges approved by the National Institute for 

Occupational Safety and Health (NIOSH) is designed 

only for low-level exposures not to exceed more than 

300 ppm. This type of respirator does not have the 

capacity to protect a person from high-level exposures. 

Clothing should be heavy duty and of a tightly 

woven fabric. Light weight, thin fabrics will not slow 

down or prevent anhydrous ammonia from passing 

through. The clothing should be tightly closed at the 

cuffs and collar to restrict the entry of anhydrous 

ammonia. 

Five gallons of fresh, clean water are to be kept 

in the emergency water reservoir on the nurse tank 

and accessible from the ground, according to North 

Dakota Century Code. Another 5 gallons should be 

maintained on the tractor for use when the nurse 

tank water may not be easily accessible or runs out. 

This water should be changed daily to keep it clean. 

Dirty water may not fl ow through the reservoir hose, 

preventing treatment of the exposure. 

Every worker should carry a 6- or 8-ounce plastic 

squirt bottle in their shirt pocket for the fi rst fl ushing 

of the eyes. It should be used immediately and is 

intended to give the victim time to get to the 5-gallon 

supply. 

Protective Equipment for 

Bulk Storage Facilities

Additional protective equipment is required for 

bulk storage of anhydrous ammonia. A rain suit

and two canister-type gas masks are required by 

law in the North Dakota Century Code (Figure 1). 

They will protect you only in areas of low ammonia 

concentrations. A cartridge-type respirator is not 

approved for use at a bulk storage facility.

Call the local fi re department if a major leak 

occurs. The fi re department has self-contained 

breathing apparatus (SCBA) and protective suits. 

SCBA units supply air to breath, rather than just 

fi ltering available air. The protective suits are 

sealed to keep anhydrous ammonia out. 

A water reservoir of at least 150 gallons of 

clean water must be available at a bulk facility, 

which would enable a person to submerge 

in water should he or she be exposed to 

anhydrous ammonia. A minimum 150-gallon 

stock water tank will meet this requirement. 

Keep the informative decals on the 

equipment up to date. The decals indicate what 

each system component does and identifi es the 

fi rst aid water, other protective equipment and 

protective procedures. 

Keep the operator’s manual for the bulk 

storage unit in a readily available place for 

reference when handling the ammonia. Review 

the instructions when needed.

Figure 2. Bleeder Valve 

Nurse Tank 

Safety Check

Bleeder Valves

The bleeder valve is used to bleed or drain pressurized 

anhydrous ammonia from a closed hose or valve 

(Figure 2). Opening a bleeder valve will release 

pressurized anhydrous ammonia slowly to minimize 

the risk of a sudden release and exposure. Bleeder 

valves should be opened slowly. Always position 

yourself upwind or across wind from a bleeder valve 

to be opened. Never disconnect a nurse tank hose 

without fi rst draining it with the bleeder valve. Bleeder 

valves are used in several processes of handling 

anhydrous ammonia.
6

Nurse Tank Hose

The nurse tank hose should be inspected daily. 

It must be maintained in a safe condition since it 

transfers anhydrous ammonia under high pressure 

from the nurse tank to the applicator tool bar. 

Although the hose is protected by an excess fl ow 

valve in the liquid withdrawal valve on the nurse 

tank, the hose must be in good condition to prevent 

an uncontrolled release (Table 3, Nurse Tank Hose 

Safety Checklist).

The nurse tank hose must be made of approved 

materials and braiding, such as rayon, rylon/Kevlar 

or stainless steel. A hose made with rayon braiding is 

good for two years from date of manufacture while 

a hose with nylon/Kevlar is good for four years from 

date of manufacture and stainless steel is good for six 

years from date of manufacture (Figure 3). 

The nurse tank hose always should be “parked” 

or attached to the Acme “parking” fi tting on the 

nurse tank when not in use during the season. Do 

not drape a hose over any edge that allows the hose 

to become fl at. During the off-season, the hose 

should be stored in a vertical position, hanging from 

the shoulder of a coupling in a cool, dry location. 

Most hose failures occur within 12 inches of the 

hose end due to fl exing of the hose while attached to 

the nurse tank or applicator. Select hose fi ttings that 

will provide the most support and minimize this type 

of fl exing. Examine the hose carefully before making 

connections to fi nd problems that may cause a hose 

failure.

Figure 3. Nurse Tank Hose 

NYLON ANHYDROUS AMMONIA-350 PSI MAX WP 1991-RMA-TFI-167-DE2

Manufacturer

I.D.

Manufacturing

Date

Working 

Pressure

Hose Type

Nurse Tank

The tank must conform to design guidelines provided 

by the American National Standards Institute (ANSI). 

The tank and all of its fi ttings, including pressure welds, 

fi ttings, gauges, hoses, safety valves and metering 

devices, must withstand a minimum working pressure 

of 250 psi (Figure 4).

The tank should be painted silver or white to 

reduce temperatures and pressures resulting from 

solar heating. Surface defects, such as rust, dents and 

gouges, reduce the integrity of the tank as a highpressure container and are not acceptable. North 

Dakota Century Code specifi es that less than 10 

percent of the surface may be corroded or missing 

paint. 

Table 3. Nurse Tank Hose 

Safety Checklist.*

Nurse Tank Hose OK Not OK

Cuts or Abrasions

Soft Spots/Bulges

Blistering/Loose Layers

Kinking/Flattening

Coupler/Hose Slippage

Type of Fittings (correct metals)

Current Dated Hose

*If any of these checklist items are “not OK,” the nurse tank 

hose should be replaced.

**“Anhydrous Ammonia,” maximum working pressure, 

manufacturer’s name/trademark, year of manufacture.
7

The nurse tank hose should have an Acme 

“parking fi tting” to be “parked” on when not in use. 

The fi tting should be installed in such a position that 

prevents strain on the hose when it is “parked.” 

The tank must be labeled correctly on each 

end and side with the green diamond around the 

words DOT (Department of Transportation) “NONFLAMMABLE GAS” and on each side and end with 

“Anhydrous Ammonia” in letters not less than 2 inches 

high. Safety and fi rst aid instructions must be on the 

tank. All valves must be identifi ed as to liquid or vapor 

service. 

North Dakota law requires anhydrous ammonia 

nurse tanks, empty or full, to display either a slow 

Figure 4. Applicator Tank 

and Valves

Applicator Tank and Valves

Pressure Gauge Liquid Fill Valve

Safety Relief Valve Fixed Liquid 

Level Gauge

Liquid Level 

Float Gauge

Liquid Withdrawal Valve Vapor Valve

Nurse Tank and Valves

Liquid Withdrawal Valve

Liquid Fill Valve

Pressure Gauge

Fixed Liquid Level Gauge

Vapor Valve

Liquid Level Float Gauge

Liquid Level 

Float Gauge

Safety Relief Valve

Drain

Hose

moving vehicle (SMV) sign or a lighted rotating or 

fl ashing amber light while on a public roadway. Any 

vehicle or towed trailer/wagon displaying an SMV sign 

is restricted to a road speed of not more than 25 miles 

per hour. Anhydrous ammonia nurse tanks, therefore, 

cannot be towed at a speed exceeding 25 miles per 

hour. 

The protective equipment kit, containing gloves 

and goggles, must be attached to the tank and 

accessible from the ground. The emergency water 

reservoir also must be attached to the nurse tank and 

be fi lled with 5 gallons of clean, fresh water. The water 

should be changed at least daily because it can absorb 

ammonia from the immediate environment. 
8

Nurse Tank Gauges and Valves

Regularly scheduled maintenance must be conducted 

to ensure that the gauges and valves on a nurse 

tank are suitable for service. The degree of hazard 

increases as parts get older. A visual inspection should 

be completed before each use. 

Some nurse tank components have a service 

life limitation based on time. The service life cannot 

be extended. Use a checklist to keep an accurate 

inventory when parts need to be replaced. A 

suggested checklist is provided in Table 5, Nurse 

Tank Valve and Gauge Safety Checklist. When a 

component is found to be defective, it must be 

repaired or replaced.

The liquid withdrawal valve (Figure 4) connects 

the nurse tank hose to the interior of the nurse tank 

for removal of the ammonia. The intake for this valve 

reaches nearly to the bottom of the tank so that liquid 

ammonia will be withdrawn until the tank is nearly 

empty. It contains an excess fl ow valve preventing

anhydrous ammonia from fl owing out of the tank 

too quickly if the nurse tank hose breaks (Figure 5). 

The excess fl ow valve has a fi ve-year replacement 

requirement. 

The liquid fi ll valve (Figure 4) is used while fi lling 

the nurse tank from a bulk storage facility. It has an 

excess fl ow valve preventing anhydrous ammonia 

from fl owing back out of the nurse tank if the 

hose breaks. This valve has a fi ve-year replacement 

requirement. 

The pressure gauge (Figure 4) indicates the 

interior pressure of the nurse tank. This interior 

pressure is affected by the quantity and temperature 

of the anhydrous ammonia in the tank. The pressure 

gauge does not have a time limit to its service life, so 

Figure 5. 

Excess Flow Valve 

Table 4. Nurse Tank 

Safety Checklist.

Nurse Tank OK Not OK

Paint

Rust

Dents

Gouges

Parking Fitting for Hose

DOT Decals

Anhydrous Ammonia Decals

Safety Decals

First Aid Decals

Valve Labeling Decals

Slow Moving Sign

Safety Kit (gloves, goggles)

First Aid Water

Table 5. Nurse Tank Valve and 

Gauge Safety Checklist.*

Nurse Tank Hose OK Not OK

Liquid Withdrawal Valve 

(5-year replacement)

Excess Flow Valve 

(5-year replacement)

Liquid Fill Valve 

(5-year replacement)

Pressure Gauge

Vapor Return Valve 

(5-year replacement)

Liquid Level Float Gauge

Hydrostatic Relief Valve

Bleeder Valves

Pressure/Safety Relief Valve 

(5-year replacement)

Roll Cage for Valves/Gauges

Tank Drain

*If any items are marked “Not OK,” they should be replaced.
9

it needs to be replaced only when it fails to function 

properly. 

The fi xed liquid level gauge is a bleeder valve 

with a tube extending into the tank to a depth where 

the tank would be 85 percent full of liquid (Figure 

6). The valve should be partially opened when the 

tank is being fi lled so it will bleed off, or spurt, liquid 

anhydrous ammonia when the tank is 85 percent full. 

The gauge is accurate only if the tank is level. Do not 

continue fi lling the tank after the valve releases liquid 

anhydrous ammonia.

The vapor return valve is used while fi lling 

the nurse tank at a bulk storage facility. As liquid 

anhydrous ammonia is transferred into the nurse tank, 

the vapor in the nurse tank is transferred to the bulk 

storage tank. The vapor valve has an excess fl ow valve 

(which has a fi ve-year replacement requirement). 

The excess fl ow valve prevents release of anhydrous 

ammonia vapors from the nurse tank if the vapor valve 

fails. 

A hydrostatic relief valve should be used anywhere 

anhydrous ammonia may be trapped in any section 

of the liquid or vapor lines of the system (Figure 7). 

It opens at 365 psi to relieve excess pressure due to 

liquid expansion.

The liquid level fl oat gauge indicates the level of 

liquid anhydrous ammonia in the tank (Figure 8). The 

fi xed liquid level gauge (Figure 4) should be used to 

determine the 85 percent full level when fi lling the tank 

instead of the liquid level fl oat gauge.

The safety relief valve also is known as the 

pressure-relief valve. This valve is on top of the 

tank (Figure 4) and prevents excessive pressure 

from building up in the tank caused by overfi lling 

or expansion from heat (Figure 9). The valve opens 

directly to the atmosphere when the tank reaches 250 

to 265 psi and closes when the interior pressure drops 

below 250 psi. It must be replaced every fi ve years if it 

has nonmetallic seats and tested every fi ve years in lieu 

of replacement if it has metallic seats. Repairs can be 

done only by a repair organization with a valid “VR” 

certifi cate of authorization from the National Board 

of Boiler and Pressure Vessel Inspectors. This valve 

must have a rain cap in place to prevent damage from 

moisture and corrosion. The safety relief valve is not 

adjustable and should be replaced if it is inoperable.

The rotary gauge (Figure 10) mounted on the end 

of an anhydrous ammonia tank, bulk tank, nurse tank 

or applicator tank consists of a dip tube inside the tank 

and a bleeder valve. This gauge is used to determine 

the actual level of anhydrous ammonia in the tank. It is

accurate only if the tank is level. The indicator shows 

Figure 6. 

Fixed Liquid 

Level Gauge

Figure 7. Hydrostatic 

Relief Valve

Figure 8. Float Gauge

Figure 9. 

Pressure-relief 

Valve

Figure 10. Rotary Gauge

Dial Indicator (in %)

Pointer

Tube

(turns with

pointer)
10

Figure 11. 

Back-check Valve

the liquid level in the tank when the bleeder valve is 

opened and the knob is rotated to the point where 

liquid spurts from the bleeder valve.

Back-check valves (Figure 11), part of the bulk 

storage facility, are used to control the direction of 

fl ow of anhydrous ammonia when unloading a truck 

or rail tank car, preventing a backfl ow from the bulk 

tank to the truck or rail tank car. A fl ow in the wrong 

direction causes the valve to snap shut. It will open 

only when the direction of fl ow is correct.

The emergency shut-off valve is another valve not 

found on a nurse or applicator tank (Figure 12). It 

also is part of the bulk storage facility used to stop the 

fl ow of anhydrous ammonia when the operator of the 

facility detects an emergency situation and decides to 

stop the transfer of anhydrous ammonia immediately. 

This valve is on the discharge side of the transfer 

pump.

The roll cage protects gauges and valves if the 

nurse tank rolls over. The roll cage must be strong 

enough to prevent damage to the gauges and valves.

Nurse Tank Running Gear

The nurse tank running gear should be inspected 

before each use. Refer to Table 6 for a suggested 

safety checklist.

The use of a safety clip on the hitch pin when 

towing anhydrous ammonia nurse tanks on and off the 

road is essential to your safety and that of the public. 

The safety clip will keep the hitch pin from working 

out and releasing the nurse tank. 

Always attach safety chains when towing 

anhydrous ammonia nurse tanks on public roads. 

Safety chains are required by North Dakota law. The 

safety clip will keep the hitch pin from working out 

and releasing the nurse tank. The chains help ensure 

that the vehicle towing the nurse tank will remain in 

control of the nurse tank if the hitch pin fails. 

Check the air pressure in the tires each time the 

nurse tank is used and inspect them for cuts, bruises 

and tread wear. Tires used on nurse tanks are designed 

for low-speed travel not to exceed 25 mph. Follow the 

restricted speed requirements for anhydrous ammonia 

both on and off the road. 

Inspect the nurse tank wagon frame before each 

use. inspecting for cracks, broken welds and bent 

members. The bolts and nuts that attach the tank 

to the frame are especially subject to loosening or 

breaking. 

Wheel bearings should be checked and repacked

annually. Steering systems should be checked regularly

and lubricated.

Figure 12. 

Emergency 

Shut-off Valve

Operating Lever

Cable Attachment for

Remote Release

Poppet

Table 6. Nurse Tank Running 

Gear Components.

Items to Check OK Not OK

Hitch Pin and Safety Clip

Safety Chains and Hooks

Lug Nuts Tight On Wheels

Tire Pressure

Good Tires

Solid Frame, No Cracks

Free-rolling Wheels

Proper Steering

Tank Secure
11

Anhydrous Ammonia 

Applicator Components

The breakaway coupler (Figure 13) is designed 

to prevent an uncontrolled release when a 

nurse tank releases from the applicator and 

the nurse tank hose separates. A spring-loaded 

valve closes when the coupler separates from 

the main body to prevent anhydrous ammonia 

from fl owing out of the hose or the applicator. The breakaway coupler is dated and has a 

service life of three years. The replacement date 

is stamped on the coupler.

Follow these steps to reconnect a breakaway 

coupler:

 1. Put on the gloves and goggles from the 

emergency kit on the nurse tank. Make sure 

emergency water is available.

 2. Check the wind direction. Always stand upwind 

when handling ammonia equipment so that 

ammonia vapors blow away from you.

3. Pick up the hose from the ground and place it on 

the tank or applicator so it is not in the way when 

reattaching the nurse tank and the applicator.

Figure 13. Breakaway Coupler

Male Coupler

O-Ring Seal

Female Coupler

Mounting Bracket

Locking Balls

 4. Make necessary hitch repairs or replacements 

and reattach the nurse tank to the applicator, 

using a safety clip on the hitch pin and the nurse 

tank safety chains.

 5. Close the nurse tank liquid withdrawal valve, 

nurse tank hose valve and the applicator fl ow 

meter. Failure to close any of these valves may 

result in a dangerous spray of ammonia.

 6. Point the hose end away from you and close the 

hose end valve. Point the bleed hole away from 

your face and slowly open the bleeder valve.

 7. Stand so that your face is away from the 

opening of the bleeder valve on the breakaway 

coupler. Slowly open the bleeder valve on the 

breakaway coupler unit. Keep the bleeder valves 

open until all reconnections have been made. 

Liquid ammonia in the hose can vaporize and 

pressurize the hose after the hose valves are 

closed.

 8. Open the applicator fl ow meter shut-off valve to 

prevent pressure from building in the applicator 

fl ow meter system.

 9. After the ammonia has been drained from the 

hose and breakaway coupler body, clean all soil 

and debris from the hose end and breakaway 

coupler fi tting. Soil or debris can interfere with 

the applicator fl ow metering system.

10.Insert the male coupler (hose end fi tting) back 

into the female coupler of the breakaway 

coupler unit. Be sure the couplers are securely 

reattached.

11. Close the applicator fl ow meter and all bleeder 

valves that were opened.

12. Open the nurse tank liquid withdrawal valve and 

hose end valve when ready. If all connections 

are tight and do not leak, replace the gloves and 

goggles in the nurse tank emergency kit.
12

Follow the instructions for your particular 

breakaway valve if they differ from the instructions 

listed above. However, never modify the written 

instructions by changing or eliminating steps. 

Safety features should be checked each time

before using the equipment in the fi eld. See Table 7 

for a checklist to prevent forgetting a safety check. 

Always use a hitch pin with a safety clip to 

be sure the nurse tank will not detach from the 

applicator and the applicator will not detach from 

the tractor. Use the safety chains when moving 

equipment on public roads. 

The condition of the applicator knives is 

important for safety reasons as well as quality 

application. Knives in poor condition may result 

in frequent stops for cleaning and unplugging, 

increasing exposure to anhydrous ammonia. Plugged 

knives can trap pressurized ammonia that will be 

released when the knife is cleared. 

Sagging low-pressure discharge hoses are a 

source of exposure to anhydrous ammonia because

the anhydrous ammonia in the sag will fl ow toward 

the applicator knife and be released when the 

machine is lifted out of the ground. All low-pressure 

tubes on the applicator should be of the same length 

for a uniform delivery to the knives. Extra hose

lengths can be coiled and securely fastened to the 

frame to reduce sagging. 

When unplugging metering screens, close the 

liquid withdrawal valve on the nurse tank and the 

hose valve on the applicator, open the bleeder valve 

on the applicator side of the nurse tank withdrawal 

valve and turn the applicator to bleed the distribution 

system. Leave the system open until the screen is 

cleaned and replaced. 

Table 7. Applicator Components.

Item to Check OK Not OK

Breakaway/Quick Coupler 

(3-year service life)

Safety Locking Hitch Pin

Safety Chain Attached

Shut-off Mechanism Valve 

and Controls

Applicator Knife Condition

Knives Not Plugged

All Fittings Tight

Low-pressure Tubes In 

Good Condition 

(no cuts, etc.)

Low-pressure Tubes 

Securely Coiled

No Sags in Coils of Lowpressure Tubes

No Kinks in Low-pressure 

Tubes

Manifold Secure and 

Mounted Level

Regulator Working Properly

Regulator Screen is Clean
13

Safe Field Practices

■ Always have an 8-ounce squirt bottle of 

water available when working with any 

anhydrous ammonia equipment. 

■ Wear gloves and goggles when connecting 

or disconnecting nurse tanks and applicators. 

■ Always have a backup set of gloves, goggles, respirator with approved cartridge 

and 5 gallons of fresh water when applying 

or transporting anhydrous ammonia nurse 

tanks. 

■ Always work upwind of anhydrous ammonia equipment. 

■ Carry the nurse tank hose by the valve 

body or coupling rather than by the valve 

wheel or control handle. 

■ Clean hose/applicator connectors before 

connecting them. 

■ Hand tighten the valve wheel; overtightening can damage the valve or seals. 

■ Follow the recommended procedure for 

connecting and disconnecting nurse tanks 

and applicators.

Transport Safety 

Practices

Highway towing rules:

■ Tow no more than two portable tanks 

behind one vehicle.

■ The speed limit is 25 miles per hour.

■ The overall length of the entire transporting 

unit may not exceed 75 feet.

■ Nurse tanks can be transported only on 

public roads between sunrise and sunset.

■ A slow moving vehicle (SMV) emblem or 

a lighted rotating or fl ashing amber light 

must be displayed on the rear of the towed 

nurse tank.

■ Safety chains must be used if nurse tanks 

are towed faster than 15 miles per hour.

■ Tanks must be identifi ed in the front 

and rear and both sides with the words 

“ANHYDROUS AMMONIA” in letters not 

less than 2 inches high.

■ Tanks must be placarded in the front and 

rear and on both sides with approved 

Department of Transportation (DOT) 

“NON-FLAMMABLE GAS” placards.

■ The DOT “NON-FLAMMABLE GAS” 

placard (“1005” decals) are also required 

to be on the nurse tank.

Should a mishap occur while transporting 

anhydrous ammonia, the spill or leak should 

be approached from upwind whenever 

possible. To minimize the gas cloud, water 

should be sprayed on the point of discharge, 

not just on the tank. If emergency help is 

needed, call toll-free 1-800-472-2121 or 911.
14

Private Stationary 

Storage Facilities

Stationary storage facilities not used for retail 

sales or disbursement of anhydrous ammonia 

are required to have the same safety facilities 

as commercial stationary storage facilities. The 

requirements are based on the storage capacity 

of the facility, regardless of whether retail sales 

are being conducted or not.

Required Safety Equipment

The following items are required at anhydrous 

ammonia bulk storage facilities:

1. A loading platform because climbing or standing 

on the wheels of nurse tanks is not permitted 

while fi lling nurse tanks 

2. A safety shower or an open water reservoir 

capable of holding at least 150 gallons of water

for complete body immersion

3. A fi re extinguisher

4. A telephone or a two-way FM radio

Personal Protective Equipment

The following fi ve personal protective equipment 

items are required by the North Dakota Anhydrous 

Ammonia Law to be readily available at the 

storage site:

1. Two full-face gas masks with spare ammonia

2. One pair of ammonia-impervious, protective 

gloves

3. One pair of nonvented goggles that meet ANSI 

Z87.1 impact specifi cations

4. One pair of impervious protective boots

5. One “slicker suit,” a rain suit that is impervious to 

ammonia

Operators of anhydrous ammonia storage facilities must be trained in safe operating procedures and 

the training documented by signed forms showing 

the type of training, the date of training, the persons 

trained and the person doing the training. These 

forms must be on record for at least three years and 

available for review at the facility during normal business hours.

Farm Transfer Facilities

Agricultural producers can transfer anhydrous 

ammonia only from cargo tanks to nurse tanks when 

the following safety requirements are met:

1. The transport tank must have complete, up-to-date 

certifi cation and labeling. 

2. Wheel chocks of adequate size must be used on 

the transport tank and the nurse tank before the 

transfer processes begin. 

3. The following articles must be on the transport 

tank: 1) a 5-gallon reservoir of clean water, 2)

ammonia-impervious gloves, 3) two full-face piece 

respirators with ammonia canisters and nonvented 

goggles. 

4. The following articles must be on nurse tanks: 

1) a 5-gallon reservoir of clean water, 2) a legal 

decal illustrating the step-by-step ammonia transfer 

process and 3) a legal decal explaining fi rst aid 

procedures to follow when exposed to anhydrous

ammonia. 

5. The transfer process must be done on a fi rm, wellprepared, level surface during daylight hours on the 

owner’s or consignee’s property; 

The following minimum setback distances apply to 

transfer facilities:

1. 50 feet from any adjoining property or any 

highway or railroad mainline 

2. 450 feet from any residence or public assembly 

3. 750 feet from any institutional residence 

4. one mile from any city limits 

Transport tank truck owners must provide written 

notice to the board of county commissioners of the 

intention to transfer anhydrous ammonia from any 

transport tank to nurse tanks in the particular county.
15

Rules for Anhydrous Ammonia Nurse Tank 

and Storage Container Locks 

The North Dakota Legislature adopted the 

following rules as a pilot project for locking 

anhydrous ammonia tanks in several North 

Dakota counties. The pilot project is coordinated 

by the North Dakota Insurance Commission, 

Anhydrous Ammonia Inspection Offi ce, State 

Capitol, Fifth Floor, 600 East Boulevard Ave., 

Bismarck, ND 58505-0320. These rules are 

included in this publication as recommended 

practices for anyone working with anhydrous 

ammonia in agriculture. More information can be 

obtained by contacting the Anhydrous Ammonia 

Inspection Offi ce by telephone at (701) 328-0440 

or e-mail at insurance@nd.gov.

1. An owner or operator of an anhydrous ammonia 

storage facility may not fi ll a nurse tank or 

applicator tank unless the tank is equipped with an 

approved locking device.

2. Unless an anhydrous ammonia nurse tank or 

applicator tank is empty, an owner or operator of 

an anhydrous ammonia storage facility may not 

store an unattended nurse tank or applicator tank 

at a facility unless the tank has an approved locking 

device installed. 

3. Unless an anhydrous ammonia nurse tank or 

applicator tank is empty, a person in possession of 

the tank outside of an anhydrous ammonia storage 

facility must install an approved locking device on 

the tank if the tank is left unattended overnight.

4. Unless a locking device is integral to the liquid 

withdrawal valve, a person transporting a nurse 

tank or applicator tank must remove the locking 

device during transit.

5. An anhydrous ammonia storage facility owner or 

operator must be present at the pickup of a nurse 

tank or applicator tank at an anhydrous ammonia 

storage facility unless the tank is empty or unless 

an approved locking device is installed on the tank.

6. A person in possession of a nurse tank or an 

applicator tank may not drop off the tank at an 

anhydrous ammonia storage facility if the owner or 

operator is not present unless the tank is empty or 

unless an approved locking device is installed on 

the tank.

7. Anhydrous ammonia may not be transferred from 

an anhydrous ammonia bulk delivery vehicle to 

a nurse tank or applicator tank unless the tank is 

equipped with an approved locking device.

8. A storage container must have approved locking 

devices installed on the main container stop valves 

whenever the storage facility is unattended unless 

the container is empty.
Summary

Anhydrous ammonia is a fertilizer commonly used 

in North Dakota agriculture. The risk of working 

with it is high because of its strong affi nity for 

water, caustic nature, high pressure and very low 

temperature created when pressure is released. 

The caustic nature of anhydrous ammonia causes 

severe chemical burning injury. The extremely low 

temperature causes frostbite and frozen tissue. 

Flushing with water is the best and only fi rst aid 

treatment for an exposure. Exposure to the eyes and 

respiratory system presents the greatest challenge 

in administering fi rst aid. The victim always should 

be taken to professional medical help as soon as 

possible. Continue to fl ush the exposure while in 

transport. 

Many safety features must be built into the 

anhydrous ammonia handling and application 

system. Some safety features have service life 

limitations supported by state laws because these 

features are not repairable in the fi eld and require 

trained technicians to service them. The purpose for 

these service life limitations is to keep these parts in 

good working condition and to minimize the risk of 

failure. 

Storing anhydrous ammonia in large bulk 

containers on the farm presents hazards similar to 

storage at commercial installations. The need for 

particular safety equipment and procedures is the 

same, regardless of the location of the facility. All 

bulk storage facilities have specifi c required safety 

equipment and procedures.

References

Aherin, R., L. Schultz, 1984. Using Anhydrous Ammonia 

Safely on the Farm, Educational Package AGEP-2192, Agricultural Extension Service, University 

of Minnesota. 

American National Standards Institute Inc., 1981. Safety 

Requirements for the Storage and Handling of 

Anhydrous Ammonia, Publication K61. 

Anhydrous Ammonia Safety, 1990. Iowa Fertilizer and 

Chemical Association. 

Doss, H.J., 1998. Preventing Ammonia Burns and How 

to Treat Them, Michigan State University Extension, 

Michigan State University. 

North Dakota Century Code, Article 7-12, Chapters 

7-12-01 through 7-12-01-08, Anhydrous Ammonia 

Regulation. 

North Dakota Century Code, Chapter 19-20.2, Sections 

19-20.2-01 through 19-20.2-10, Anhydrous 

Ammonia Facilities. 

The Fertilizer Institute, 1982. External Visual Inspection 

Guidelines for Anhydrous Ammonia Nurse Tanks 

and Applicator Tanks. 

Grisso, R.D., D. Morgan and R.D. Schnieder, 1994. 

Using Agricultural Anhydrous Ammonia Safely, 

EC94-738-B, University of Nebraska Cooperative 

Extension, University of Nebraska. 

Schutske, J.M., 1998. Using Anhydrous Ammonia 

Safely on the Farm, Minnesota Extension Service, 

University of Minnesota. 

Schwab, C.V., M. Hanna and L. Miller, 2002. Play it Safe 

with Anhydrous Ammonia, University Extension, 

Iowa State University.

 NDCC 28-32-02 Chapter 19-20.2 Anhydrous Ammonia 

Facilities. Effective April 1, 2004.

.

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