Ammonium nitrate storage and handling

Find out about specific requirements for storing and handling ammonium nitrate.

Safe storage

The safe storage of ammonium nitrate relies on the following principles:

avoiding contamination of foreign materials, especially if that material is combustible or incompatible
good housekeeping
storing the material away from heat sources and naked flames
avoiding confinement
storing away from explosives
avoiding exposure to shock
avoiding uptake of moisture (not a safety concern if ammonium nitrate is bagged)
preventing unauthorised access
being prepared for an emergency.

Safety data sheets

Obtain safety data sheets (SDSs) for ammonium nitrate from the supplier and keep in a register.
Include the name of other hazardous chemicals on site along with a copy of the SDS for each in the register.
Locate each SDS so that it is readily accessible to workers who may be affected by it. Also ensure that emergency responders have access to this information if required during an incident.

Read the SDS to identify:

the chemical and physical hazards
appropriate safe storage and handling practices
the need for additional control measures
first aid measures
firefighting and emergency information.

Safety equipment and personal protective equipment (PPE)

Provide appropriate personal protective equipment which may include:

chemical goggles or face shield
PVC or rubber gloves
PVC/rubber aprons and boots
disposable P1 respirator.

PPE should be provided for the purposes of handling the ammonium nitrate, or cleaning up spills. Advice should be sought from the SDS on what is appropriate.

Safety showers and eye wash stations should also be provided where a risk of exposure to eyes or skin exists.

Handling equipment

Protect intermediate bulk containers (IBCs) from puncturing from sharp objects (e.g. forklift tynes, protruding nails on pallets).
Avoid any hollow spaces in ammonium nitrate handling equipment where the material may collect and be confined under pressure. In the event of a fire, an explosion could result.
Clean any mechanical handling device (e.g. conveyors) to prevent build-up of debris or ammonium nitrate on the surfaces.
Keep bins and bunkers free of materials that may contaminate ammonium nitrate. Aluminium bins are suitable. Wooden bins, even if coated to prevent impregnation are not recommended.
Due to corrosive and reactive properties of ammonium nitrate, and to avoid contamination, do not use galvanised iron, copper, lead, and zinc in bins, or other handling devices (e.g. shovels or mechanical shovels) that may come into contact with the material.
Ammonium nitrate corrodes copper and copper alloys – relevant to electrical switches, cables, motors and also electronic equipment that may form part of a protection system (e.g. fire detection, control gear on conveyors, rotary valves).

Forklift trucks and vehicles

Keep forklift trucks, tractors, platform lift trucks, and other vehicles clean and maintained so that fuels (e.g. diesel) or hydraulic fluid is not contaminated by the ammonium nitrate and equipment (mobile and static should be routinely checked for oil leaks). If found, remove the leaking equipment from the ammonium nitrate area and clean up oil spillage immediately.
Internal combustion engine vehicles, lift trucks, or cargo conveyors should be:

garaged at least 10 m from any ammonium nitrate storage area
turned off while unattended inside a building where ammonium nitrate is stored
kept outside when not in use
provided with a dry powder extinguisher.

Use only electric, LPG or diesel fuelled vehicles.
Start LPG or diesel forklift trucks outside the store.
Fit vehicles powered by LPG or diesel with spark arrestors (exhaust water scrubbers).
Fit battery terminals with an insulated cover and clearly marked battery isolation switch.

Housekeeping

Clean the storage area first before placing ammonium nitrate in the area.
Keep walls, floors, access ways and surrounding areas and equipment clear and free of build-up of combustible debris, including ammonium nitrate.
Do regular inspections to ensure leaks are detected promptly and cleaned up.
Keep ammonium nitrate storage areas clean and apart from any unnecessary objects by at least 3 m in all directions (e.g. unused wooden pallets).
Clear all dry vegetation away from the store by at least 5 m.
Store filled bags and intermediate bulk containers (IBCs) in stable stacks.
Clean up spillage of ammonium nitrate and other materials stored nearby immediately.
Keep damaged bags in over packs or slip-over bags to prevent additional spillage.
Safely dispose of contaminated products or ensure they are free of ammonium nitrate.
Do not allow pallets, ropes, slings, covers, machinery, or combustible items to become contaminated with a build-up of ammonium nitrate.

Hot work and ignition sources

Do not allow ignition sources (e.g. naked flames, smoking) in ammonium nitrate storage areas.
Exclude all potential sources of heat and fire (e.g. matches, naked flames, incandescent material, and welding sparks) from any store opening by at least 3 m.
A hot work permit is required under AS1674.1-1997: Safety in Welding and Allied Process-Fire Precautions to conduct hot work (e.g. welding or cutting).
Remove the ammonium nitrate bags from the area by a safe distance or use barriers before carrying out maintenance or hot work.
Clean surfaces contaminated by ammonium nitrate before welding or hot work is done to prevent a risk of fire or explosion or release of toxic vapours.

Security, access and control of visitors

Prevent unauthorised people from accessing storage or handling areas.
Control and make visitors and contractors aware of relevant safety precautions.
Maintain up-to-date inventory to assess quantities present.
Have a systematic inventory control to monitor outgoing and incoming quantities.
Inspect storage areas each morning.
Provide adequate exterior lighting around the storage areas.
Ensure site visibility is not obstructed by shrubs.
Keep shipping/receiving paperwork in a secure place.
A security checklist providing detailed guidance on what precautions are appropriate. Consult the Department of Natural Resources and Mines' Explosives Inspectorate for further information regarding security sensitive ammonium nitrate.

Segregate incompatible materials

Ammonium nitrate is incompatible with the following materials including (but is not limited to):

all flammable and combustible liquids
all flammable solids
organic chemicals, acids, alkalis, and other corrosive materials
compressed flammable gases
other contaminating materials including:

animal fats, baled cotton, baled rags, bleaching powder, camphor, caustic soda, cement, charcoal, coal, coke, cotton bags, cork, fish meal, fish oils, foam rubber, hay, linseed oil, lubricating oils, naphthalene, oiled clothing, oiled textiles, sawdust, scrap paper, straw, timber shavings, vegetable oils or other oxidisable or drying oils.

Segregate ammonium nitrate from all other incompatible goods by 3 m or more.
Do not store ammonium nitrate fertilisers of Class 9 (UN 2071) with ammonium nitrate of class 5.1.
If one of the goods present is a liquid or if the goods may react violently with the ammonium nitrate, store them in separate compounds or at least 5 m or more apart.
Use an appropriate, inert, fire rated physical barrier (FRL 120/120/120) to achieve segregation if the distances are measured around the barrier.
Never allow incompatible goods to come into contact with the ammonium nitrate.
Provide bunds, kerbing or sloping floors to ensure that molten or liquid incompatible products cannot mix.
Do not bund ammonium nitrate.
Do not assume that all class 5.1 oxidising agents are compatible as many are not (e.g. ammonium nitrate is also incompatible with sodium nitrite, another oxidising agent). Unless proven otherwise, assume the materials are incompatible. See the product SDS for guidance.

Explosives Inspectorate

Firefighting

Although ammonium nitrate is not combustible it may present a hazard in a fire due to its strong oxidation properties, or through the evolution of toxic and irritating gases from the heat in a fire.

Firefighting facilities should be compatible with local Queensland Fire and Rescue Service equipment. Firefighting measures must include:

access to adequate supplies of water
being able to extinguish a small fire involving ammonium nitrate immediately with a hose
access to water spray to cool the adjacent store if a major fire occurs near the store
being able to direct water spray from a safe distance for large storages of ammonium nitrate
providing fixed fire detection systems to allow for early detection
installing fire hose reels where stores exceed 200 m²
As a minimum standard, firefighting measures should be provided in accordance with Section 12 of AS4326: The storage and handling of oxidizing agents. In the event of a fire, call the Queensland Fire and Rescue Service and consider evacuation to a safe place where people are not exposed to the fumes or risk from explosion.

Emergency planning

Where hazardous chemicals are used, stored and handled, emergency plans must account for the associated hazards and credible incident scenarios for those hazardous chemicals such as ammonium nitrate. In developing the emergency plan covering ammonium nitrate incidents, consider the adequacy of firefighting systems, access to and from the site, deciding a safe evacuation assembly area, the need to notify neighbouring places during an emergency, providing and testing alarms, and carrying out regular emergency drills.

Refer to the general guidance on emergency planning for hazardous chemicals.

The manifest must contain an up-to-date inventory of hazardous chemicals used, stored and handled at the workplace, including the quantity and location of each storage area. Schedule 12 of the Work Health and Safety Regulation 2011 (WHS Regulation) prescribes the information to be included in the manifest and site plan. The manifest and site plan should be kept in a red weatherproof container at the main entrance to the site.

Notification

If ammonium nitrate products classified as hazardous chemicals are used, stored or handled in excess of the manifest quantity, notify Workplace Health and Safety Queensland.

More information

More information on ammonium nitrate is available in the Australian Standard AS4326: The storage and handling of oxidizing agents.