Ammonium Nitrate Fertilizers are classified as an Oxidising Agent and although they are not combustible, in the event they are involved in a fire, may, by yielding oxygen or by similar process, increase the risk and intensity of fire in other materials with which they come into contact.

In certain cases they may also decompose in a self-sustaining manner. Toxic fumes may be liberated when they are involved in a fire and under extreme conditions there may be a risk of a violent reaction.
In view of this, the major hazards are identified as Fire, Explosion, and Toxic Fumes in the event of a Fire.

General Good Practice for Handling Ammonium Nitrate Fertilisers

Fire Prevention

• Safety procedures are therefore essential for the Handling, and Storage of these materials. The following Operational Procedures will help to reduce the risks highlighted above. Many of the procedures are aimed at reducing the possibility of a fire occurring so smoking is prohibited on site.
• Any plant or equipment that requires welding or the application of heat must be previously thoroughly washed to remove all fertiliser. A “Permit to Work” for Hot Work shall be required before any such plant or equipment is subject to any kind of “Hot Work”.
• No naked flames, welding or similar processes are to be used anywhere on the site without the knowledge and authority of the Management (or person acting on their authority).
• Unless required for heating purposes, all electrical machinery and lighting must be switched off when not in use.
• Mobile Plant & Machinery should be parked away from Ammonium Nitrate in case it catches fire.

Handling and Storage Advice

• Avoid contamination of AN. In particular ensure all storage areas are as clean and dry as is reasonably practical before storing AN therein.
• Keep equipment, walls, and floors clean and free from contaminants at all times.
• Any building used for storage of AN shall be kept as dry as is reasonably possible.
• Always ensure there is a one-metre walkway around any stack of AN in bags.
• Stacks of AN in bags should be kept to less than 300 tonnes total size. Additional stacks may be constructed in adjacent areas providing the walkways (indicated above) are strictly adhered to.
• All bagged oxidising fertilisers shall be stored immediately under the fire detection probes.
• Bags of AN (including all yellow diamond marked bags) should not be stored together in the same stack with bags of any other fertilisers.
• Any damaged bags of AN should be placed immediately into secondary bags to prevent further spillage, and the residual AN product added to the bulk screenings heap (see further note below regarding off-spec material).
• Do not store AN where it can be affected by any source of heat and keep it separate from any combustible materials.
• If Urea is stored in the same building as AN, arrange the storage so they cannot come into contact with each other in any conceivable situation, including fire.
• Store empty pallets outside (but not against) the fertiliser store, except for any which are needed for the immediate service of the packing lines. If the need arises to store the pallets inside, separate them from AN with a suitable firebreak.
• If AN is stored outside, protect the stacks from sunlight and water and cover with properly secured plastic sheeting to prevent product deterioration.
• Do not leave/park motor vehicles, including all plant e.g. forklifts and Loading Shovels, unattended close to AN storage areas. All keys must be removed from unattended vehicles.
• Ensure so far as possible that any vehicles that are permitted to enter the store are free from oil and fuel leaks. If oil or fuel leaks are discovered these should be cleaned up immediately with inert absorbent granules. The resulting material should be diluted with an inert substance such as limestone grit and disposed of in accordance with due regard for environmental considerations.
• Avoid activities such as vehicle maintenance, e.g. Hot work, welding, near to AN storage areas.
• Fertiliser sweepings, (particularly those of AN), should not be allowed to become contaminated with combustible materials. Sawdust should not be used as an absorbent to clean floors.
• To avoid environmental damage any AN spillage (and other fertiliser spillage) should be recovered as soon as possible and disposed of appropriately.
• Do not store, or load AN on the same vehicle, with any combustible substances such as hay, straw, oil, grease, petrol, paint, oil based pesticides, nor with chemicals such as acids, urea, or chlorates.

Labelling.

• Ensure all packages (bags) are clearly labeled in accordance with the Fertiliser and Carriage of Dangerous Goods Classification Packaging and Labeling Regulations (CDGCPL Regulations), and where appropriate show the oxidising agent symbol yellow diamond. Where palletised AN material is shrink-wrapped the oxidising label must be visible through the wrapping or an additional label should be fixed to the outside.
• Disposal of waste packaging etc, and Environmental safeguards.
  • Before disposal, used fertiliser bags shall be thoroughly emptied to remove all fertiliser.
  • Dispose of broken pallets, ropes or covers, damaged or discarded fertiliser bags using locally available facilities for waste disposal.

Other Assistance

http://www.secureyourfertiliser.gov.uk/