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Secured and safe transportation, storage and handling of Ammonium Nitrate


Author: Partha Das Sharma, B.Tech(Hons.) in Mining Engineering; E.mail:; Blog/Website: 1. Introduction - Ammonium nitrate (AN) is almost infamous for its potentially explosive properties, mainly due to a series of serious accidents in the first half of the 20th century, and thereafter, its use in terrorist weapons. Ammonium nitrate (NH4NO3) is a hygroscopic (water-absorbing), colourless, crystalline solid that is very soluble in water. It is classed as an oxidising agent but has explosive properties. Ammonium nitrate primarily is used as a fertilizer, it also is used widely with additives as a blasting agent. In fact, a considerable amount of ammonium nitrate is used as blasting agent (ANFO) and used as a solid oxidizer ingredient for various emulsion and slurry explosive compositions. They are marketed either as melt (AN solution), prills (small spheres) or granules. Ammonium nitrate, irrespective of its grade (viz., fertilizer or explosive) can be handled safely provided that reasonable precautions are taken. Many of these AN substances, including some fertilizers are also categorised as “dangerous goods� in many country. According to scientific literature, ammonium nitrate is a strong oxidizer and a relatively stable explosive. For the purpose of transportation, ammonium nitrates with less than 0.2 percent combustible substances in ammonium nitrate fertilizers are classified as oxidizers in many countries. Ammonium nitrate with more than 0.2 percent combustible substances is classified as an explosive. Ammonium nitrate can be exploded under certain conditions. These must include added energy (heat, shock), especially under conditions of confinement or presence of contaminants. Although ammonium nitrate generally is used safely and normally is stable and unlikely to explode accidentally, in the past, accidental explosions of ammonium nitrate or explosion caused by terrorists have resulted in loss of lives and destruction of property. When these explosions occur, they have high impacts. Many of the secured and safe handling procedures / guidelines developed or being developed is after learning from these accidental explosions and pilferages made by miscreants.

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Secured and safe transportation, storage and handling of Ammonium Nitrate 2. Properties of AN in relation to evaluate explosion hazard awareness – Ammonium nitrate has a melting point of 1700C and decomposes above 2100C. It is not in itself combustible but, as it is an oxidising agent, it can assist other materials to burn, even if air is excluded. Ammonium nitrate, in solid or molten form or in solution, is a stable compound and generally is difficult to explode (It do not explode due to the friction and impact found in normal handling). Ammonium nitrate may explode, however, when exposed to strong shock or to high temperature under confinement. In a large quantity of ammonium nitrate, localized areas of high temperature may be sufficiently confined by the total quantity to initiate an explosion. For example, in a fire, pools of molten ammonium nitrate may be formed and if the molten mass becomes confined (e.g., in drains, pipes, plant or machinery) it could explode, particularly if it becomes contaminated. Contaminants may increase the explosion hazard of ammonium nitrate. Organic materials generally will make ammonium nitrate explosions more energetic. Ammonium nitrate may be sensitized by certain inorganic contaminants, including chlorides and some metals, such as chromium, copper, cobalt, and nickel. As ammonium nitrate solution becomes more acidic, its stability decreases, and it may be more likely to explode. Low density areas, such as bubbles, in molten ammonium nitrate or solutions, also may increase the possibility of an explosion and enhance the propagation of an explosion. Ammonium nitrate by itself does not burn, but in contact with other combustible materials, it increases the fire hazard. It can support and intensify a fire even in the absence of air. In a fire, all types of ammonium nitrate may melt and decompose with the release of toxic fumes, which may be yellow or brown. Fires involving ammonium nitrate can release toxic nitrogen oxides and ammonia. A fire involving ammonium nitrate in an enclosed space could lead to an explosion. Closed containers may rupture violently when heated. 3. Precautions and recommendations for hazard reduction - The precautions described here are primarily designed to minimise the risk of explosion. Facilities should be aware of the hazards of ammonium nitrate and ensure that the conditions that may lead to an explosion are not present. Actions that may help to prevent explosions include: * Avoid heating ammonium nitrate in a confined space (e.g., processes involving ammonium nitrate should be designed to avoid this possibility). * Avoid localized heating of ammonium nitrate, potentially leading to development of high temperature areas. * Ensure that ammonium nitrate is not exposed to strong shock waves from explosives.

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Secured and safe transportation, storage and handling of Ammonium Nitrate * Avoid contamination of ammonium nitrate with combustible materials or organic substances such as oils and waxes. * Avoid contamination of ammonium nitrate with inorganic materials that may contribute to its sensitivity to explosion, including chlorides and some metals, such as chromium, copper, cobalt, and nickel. * Maintain the pH of ammonium nitrate solutions within the safe operating range of the process. In particular, avoid low pH (acidic) conditions. In short, the risk of an explosion is increased by a combination of the following: * Heating ammonium nitrate (e.g., in a fire); * Contamination; * Serious confinement (e.g., in drains or enclosed parts of equipment). Therefore, to minimise the risk of explosion it is important to take precautions against each of these situations. a) Storage areas : Ammonium nitrate should normally be stored in single storey, dedicated, well-ventilated buildings that are constructed from materials that will not burn, such as concrete, bricks or steel. Clean the store before it is used for ammonium nitrate. However, in some circumstances, such as where the stores are located near to densely populated areas, it may be better to store ammonium nitrate outside, provided it is in a secure area away from combustible materials and sources of contamination. Such outdoor storage can remove or reduce the risk of, for example, fires due to electric lights and other equipment. However, if ammonium nitrate is stored outdoors it may be necessary to consider methods to prevent it deteriorating due to sunlight or water (eg covering it with sheets or shrink-wrapping and ensuring that water can run away from the storage area). Avoid drains, channels or pits where molten ammonium nitrate from a fire could become confined. Where the presence of drains, etc is unavoidable, they should be protected so that molten ammonium nitrate cannot run into them. Locate storage away from possible sources of heat, fire or explosion, such as oil storage, gas pipelines, timber yards, flammable liquids, flammable solids and combustible materials. Arson and faulty or damaged electrical equipment are major risk factors for warehouse fires, so prevent unauthorised access to the store. Ensure regular inspection and maintenance of electrical equipment and fittings. --------------------------------------------------------------------------------------------------Author: Partha Das Sharma, B.Tech (Hons.) in Mining Engineering; E.mail:; Blog / Website:


Secured and safe transportation, storage and handling of Ammonium Nitrate (b) Stacks: Self-confinement of straight ammonium nitrate in large stacks can increase the risk of a detonation of the whole stack in a fire, so limit stacks to maximum permissible quantity. To help prevent fires and other heat sources from affecting stored ammonium nitrate, and to allow access to stacks in an emergency, leave a space of at least 1 m between stacks and between the stack and the walls, roof or any electric lights or heating pipes. Check the height of doors, beams and electrical equipment in relation to that of any lifting equipment used, such as fork-lift trucks. Do not allow ammonium nitrate, including when molten in a fire, to come into contact with materials such as flammable liquids, powdered metals, acids, chlorates, nitrates, zinc, copper and its salts, oils, grease, gas cylinders and chemicals of incompatible or unknown properties. Do not store ammonium nitrate in the same building as such materials. (c) General precautions: To prevent spillage and contamination make sure that the bags have been completely sealed on filling, are made of a material that is impermeable to water or oil, and are strong enough to withstand damage during normal storage, handling and conveyance. It is recommended that 50 kg bags have microvents to avoid ballooning and consequent instability in stacks. Do not store unused pallets in, or against the walls of, the store because of the increased risk of fire affecting the ammonium nitrate. Where it is necessary to keep the pallets in the store, separate them from the ammonium nitrate by a suitable fire break or partition. Prohibit smoking in all storage areas and display prominent NO SMOKING notices. Keep vehicles, fork-lift trucks and mechanical shovels clean and well maintained to prevent ammonium nitrate coming into contact with fuel, oil or grease. It is recommended that mobile equipment is fitted with suitable fire extinguishers of adequate capacity to deal with a fire on the vehicle. Do not leave such equipment running while unattended or store it in the storage area unless separated from the ammonium nitrate by a suitable fire break, preferably in a clearly marked, dedicated area. (d) Housekeeping The following precautions are also essential: * Do not use organic materials such as sawdust as an aid to cleaning floors. * Put damaged bags into overpacks, i.e., a secondary bag of sound construction that will prevent further spillage. * Promptly and safely dispose of contaminated products.

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Secured and safe transportation, storage and handling of Ammonium Nitrate * Do not allow pallets, ropes, covers, or other equipment to become impregnated with ammonium nitrate. * Keep walls, floors and equipment clean. * Locate electrical equipment where it cannot come into contact with the stored materials. * Avoid hollow sections in equipment, or where unavoidable wash them regularly (away from the storage area) to prevent any build-up of ammonium nitrate. * Ensure that bags of ammonium nitrate have been removed from the immediate area and contaminated items have been thoroughly washed to remove ammonium nitrate before allowing any maintenance that involves heat, such as welding or cutting. Apart from the risk of explosion in confined areas there is also a risk of toxic fumes being produced. (e) Fire precautions : Inform the local fire authority that ammonium nitrate is stored and agree with them the arrangements for giving early warning of a fire, providing suitable access to the site and ensuring that an adequate supply of water is available, or can be made available, to tackle an incident. Employees need to be trained and practised in the actions to take in a fire. This includes using portable fire-fighting equipment to tackle any fire in its early stages. Portable water fire extinguishers or fire hose reels are appropriate where ammonium nitrate is, or might be, involved. To enable employees to deal with such incidents, they need to receive specific training to ensure that they do not put themselves at risk of breathing fumes from decomposing ammonium nitrate. Additional safeguards may be necessary at some sites where there are large quantities of ammonium nitrate which, due to explosion or fumes in a fire, might affect neighbouring buildings or plant or pose a significant off-site risk. These safeguards may include measures to ensure that the fire brigade is called quickly, for example an automatic fire detection system or continuous supervisory staffing by workers who have ready access to a telephone. Consider the need to install a fixed water deluge system as well, which may also help limit the potential for environmental damage by contaminated water from subsequent fire-fighting. (f) Bulk AN products: There is a greater risk of an unpackaged (bulk) product becoming contaminated than there is with a packaged product. Therefore it is essential that precautions are taken to minimise the risk of contamination, especially with combustible or incompatible materials. Only store bulk ammonium nitrate inside buildings constructed as described for packaged products, or in silos made from materials that do not readily ignite, such as glass fibre reinforced plastic. Situate such silos at least 10 m from combustible materials. Due to the --------------------------------------------------------------------------------------------------Author: Partha Das Sharma, B.Tech (Hons.) in Mining Engineering; E.mail:; Blog / Website:


Secured and safe transportation, storage and handling of Ammonium Nitrate corrosive nature of ammonium nitrate, avoid using galvanised items such as sheeting, joints and girders. Keep any passage next to the storage area clean, and remove any spillage promptly, place it in a dedicated area and dispose of it as soon as possible. Decomposition could occur if heaters are positioned too near to ammonium nitrate or if dust deposits are allowed to accumulate on steam pipes or other heating devices. Do not use direct electrical heaters in ammonium nitrate stores. Ensure that light fittings are robust, made of material that does not readily burn and constructed or positioned so that ammonium nitrate dust cannot penetrate them. Locate main electrical switches, fuses, etc outside the storage area to minimise the risk of fire. It is important in harbour areas for loading and unloading facilities from ship to shore to be designed to avoid contamination. Loading and unloading during adverse weather such as rain, snow, or hail are not advisable because of the risk of caking. 4. Factors to be considered for Security of storage and transportation of AN - In order to prevent misuse of Ammonium Nitrate, in many of the countries, ammonium nitrate has been classified under “Dangerous substance�; thus, for use, storage, handling and transportation adequate security issues are to be addressed. Generally, guidance notes are designed for businesses that store and transport Ammonium Nitrate - this may include manufacturers, the mining industry, agricultural and mining suppliers, importers and exporters. 4.1. Management of security - Some of the relevant points on management of security and factors considered for framing guidance notes are discussed below: * Secure means secure from (a) Detectable theft; (b) Unexplained loss; (c) Sabotage; or (d) Unauthorised access. * Security risk means risk of (a) Theft of ammonium nitrate; or (b) Unexplained loss of ammonium nitrate; or (c) Possible sabotage of ammonium nitrate; or (d) Unauthorized access to ammonium nitrate. * Security plan means, a plan that has been put in place to effectively minimize all security risks relevant to the transport of AN. The security plan begin with a security risk assessment, to provide information to the regulatory authority about current security measures and about the risk of theft, unexplained loss, sabotage and unauthorised access. It provides information to the regulatory authority about how businesses meet security requirements. * Secure location means, a secure (e.g. fenced and entry controlled) place where facilities and a management structure exists which ensures accountability for both documenting and receiving or dispatching known quantities of AN. --------------------------------------------------------------------------------------------------Author: Partha Das Sharma, B.Tech (Hons.) in Mining Engineering; E.mail:; Blog / Website:


Secured and safe transportation, storage and handling of Ammonium Nitrate * Constant surveillance means, the presence of an alert and authorised person, or the continuous monitoring by video or electronic surveillance. 4.2. Minimum security requirements - The minimum security requirements are: (i) Precautions to ensure the AN is secure for the duration of the entire journey while transportation; (ii) Procedures for checking and authorising persons; (iii) Designation of a responsible person/security manager to maintain the security plan; (iv) Record keeping to reconcile any stored, incoming and outgoing quantities of AN and to ensure that AN is obtained from an authorised person and supplied to an authorised person; (v) Procedures for reporting to authorities any loss, theft, attempted theft or any other security incident involving AN. 4.3. Security risk assessment - A security risk assessment is a necessary preamble to developing a security plan. The assessment should describe existing security measures and examine the level and type of security risks to the particular business. In clarifying those risks it is necessary to consider outside threats and also the security risk from staff or contractors who have access to transport vehicles and ammonium nitrate. The risk assessment will document the transport routes to be used and consider the security risks relevant to these routes. Consider whether current security arrangements leave the ammonium nitrate vulnerable to theft or sabotage, and consider security improvements to manage the assessed risk as well. Security assessments should be reviewed periodically, particularly after a security incident. 4.4. Security plan - The security plan should have four main elements: (a) Personnel management – (i) List of authorised persons; (ii) Maintaining the security plan that must include the nomination of a responsible person/security manager to implement and maintain the security plan including the instruction of workers in the relevant access controls, recording procedures and reporting of security incidents. (b) Site security – (i) Transport must be from one secure location to another; (ii) Constant surveillance may be necessary at locations identified as high risk. (c) Load security – (i) The security plan must contain details of your secure transportation arrangements, including the usual route traveled; (ii) Road vehicles should not be left unattended in transit. (d) Procedures – (i) Persons having unsupervised access to consignments of AN must be clearly identified in the security plan; (ii) Monitoring of the consignment’s location while in transit; (iii) Record keeping and inventory/consignment procedures should be in place. (e) Emergency plans - Storing or transporting companies must have sound emergency plans in place to help mitigate the size and impact of any emergency. Emergency plans should include training and drills, and reviews of the plan and storage facilities by relevant emergency services agencies. --------------------------------------------------------------------------------------------------Author: Partha Das Sharma, B.Tech (Hons.) in Mining Engineering; E.mail:; Blog / Website:


Secured and safe transportation, storage and handling of Ammonium Nitrate The above requirements may need to be complemented with additional measures, depending on the security risk. While theft of part of a load is one risk, consideration should also be given to the risk of the vehicle itself being stolen or commandeered. Additional measures to manage this risk could include improved cabin security and procedures, and advanced communication systems to monitor the movement of vehicles. Moreover, consider any measures that would usefully improve the security of business. Note - In India, to curb the misuse of Ammonium Nitrate, Ministry of Home Affairs (MHA), Govt. of India, has issued new rules. The relevant points according to the new Ammonium Nitrate Rules, 2009(draft) are discussed below: * The manufacture, possession, sale, and usage is regularised and any violation will be viewed seriously. * The security management plans to ensure safety of factories manufacturing ammonium nitrate, its transport, storage and usage would be in place and would require permits. * Any new manufacturer shall get permission and all the existing units have to get permits within six months of the notification of the rules. * As per the new rules it shall not be used for blasting either alone or in combination unless permitted under the explosives rules. * As per the rules, audit and electronic bar coding has to be done by the manufactures to avoid any illegal production or import of Ammonium Nitrate. * The permit holder has to hire security guards for safe custody of Ammonium Nitrate stored in a storehouse at his own cost. * Records of the stocks shall be maintained at all levels from manufacture to usage and during transport there shall be a pass issued by district authority and a copy of it has to be submitted to district superintendent of police of the place to which the consignment is sent. * The truck carrying Ammonium Nitrate shall not stop for a longer period than is reasonably required and shall avoid stopping at a place where public safety is in danger. 5. Additional points to be remembered about Ammonium Nitrate (explosive grade): * Low density ammonium nitrate is used extensively in the mining industry and is intentionally made very porous to allow for the rapid uptake of liquid fuel oil. The prill is coated with paraffin which makes the ammonium nitrate difficult to dissolve and use for other applications. --------------------------------------------------------------------------------------------------Author: Partha Das Sharma, B.Tech (Hons.) in Mining Engineering; E.mail:; Blog / Website:


Secured and safe transportation, storage and handling of Ammonium Nitrate * Ammonium nitrate will decompose into ammonia and nitric acid fume at 350oF. * Always wash vessels containing ammonium nitrate thoroughly before attempting repairs requiring welding. * Always keep doors, hatches and lids closed when not in use. Inspect all tanks and bins regularly for cracks and leaks. * Industrial grade prilled ammonium nitrate is susceptible to breakage from moisture, humidity, heat, temperature cycling, pressure and pneumatic or mechanical handling. Fines can result producing possible caking or lumping as well as decreased product flow characteristics / increased bulk density. * Always design storage and process facilities to minimize repeated pneumatic and mechanical handling. Whenever possible, choose mechanical rather than pneumatic methods to off-load or otherwise transfer ammonium nitrate prills. * Always use an air transfer pressure of 7–8 psig to maintain prill quality where bulk deliveries are transferred to storage by pneumatic conveyance. * Never exceed 8-10 psig air pressure. * Always use equipment especially designed to blend and load ANFO, Heavy ANFO or repumpable emulsion / ANFO blends. Bulk delivery equipment should be calibrated periodically to ensure quality. * Always purge all hoses, piping, augers and especially bins or tanks that have integral augers before discontinuing loading or mixing. Ammonium nitrate prill left in process equipment can make start up difficult and even cause damage. * Always consider air vibrators for bins, bulk trucks and railcars to assist with the flow of material. 6. Safe practices in Transportation, Storage and Handling of AN (explosive grade): * Oxidizers must be transported, stored, handled and used in conformity with all applicable federal, state, provincial and local laws and regulations. * Unauthorized access to industrial grade ammonium nitrate must be denied at each step during transportation and storage. * Always rotate inventory by using the oldest product first. * Always choose bins and tanks that are designed to keep the weight of the bulk material from compacting into transfer augers that are located directly beneath them. --------------------------------------------------------------------------------------------------Author: Partha Das Sharma, B.Tech (Hons.) in Mining Engineering; E.mail:; Blog / Website:


Secured and safe transportation, storage and handling of Ammonium Nitrate * Always empty and clean bulk tanks and bins routinely to prevent product build-up on walls. * Always minimize inventory during warm weather and high humidity conditions. Packaged product may harden with temperature cycling; bulk material may cake, lump or break down (fines). * Always keep prilled ammonium nitrate dry. Choose transportation, processing and storage containers or equipment without openings though which water or moisture can enter 7. Hazardous Shipping Description of Ammonium Nitrate: Ammonium Nitrate 5.1 UN1942 III or Ammonium Nitrate Fertilizer 5.1 UN2067 III. The United Nations Model Regulations on the Transport of Dangerous Goods provide a basis for development of harmonized regulations for all modes of transport, in order to facilitate trade and the safe, efficient transport of hazardous materials. The UN Model Regulations is in its 13th edition and is the basis for most international, regional, national and modal transportation regulations. The UN Model Regulations enhance safety, improve enforcement capability, ease training requirements and enhance global trade and economic development. Safety is enhanced primarily because harmonized requirements simplify the complexity of the regulations, simplify training efforts, and decrease the likelihood of non-compliance. The Model Regulations provide economic benefits by eliminating the costs of complying with a multitude of differing national, regional and modal regulations. The UN Model Regulations facilitate compatibility between modal requirements so that a consignment may be transported by more than one mode without intermediate reclassification, marking, labeling or repackaging. References: * * Health and Safety Executive. United Kingdom. 2001. * United Nations Model Regulations on the Transport of Dangerous Goods; * The Notification of Installations Handling Hazardous Substances Regulations 1982 SI 1982/1357 HMSO ISBN 0 11 027357 5 * The control of fire-water run-off from CIMAH sites to prevent environmental damage EH70 HSE Books 1995 ISBN 0 7176 0990 1 --------------------------------------------------------------------------------------------------Author: Partha Das Sharma, B.Tech (Hons.) in Mining Engineering; E.mail:; Blog / Website:


Secured and safe transportation, storage and handling of Ammonium Nitrate * * Draft Ammonium Nitrate Rules, 2009, ---------------------------------------------------------------------------------------------------------Author’s Bio-data: Partha Das Sharma is Graduate (B.Tech – Hons.) in Mining Engineering from IIT, Kharagpur, India (1979) and was associated with number of mining and explosives organizations, namely MOIL, BALCO, Century Cement, Anil Chemicals, VBC Industries, Mah. Explosives etc., before joining the present organization, Solar Group of Explosives Industries at Nagpur (India), few years ago. Author has presented number of technical papers in many of the seminars and journals on varied topics like Overburden side casting by blasting, Blast induced Ground Vibration and its control, Tunnel blasting, Drilling & blasting in metalliferous underground mines, Controlled blasting techniques, Development of Non-primary explosive detonators (NPED), Hot hole blasting, Signature hole blast analysis with Electronic detonator etc. Author’s Published Book: "Acid mine drainage (AMD) and It's control", Lambert Academic Publishing, Germany (ISBN 978-3-8383-5522-1). Currently, author has following useful blogs on Web: • • • • Author can be contacted at E-mail:,, ------------------------------------------------------------------------------------------------------------------Disclaimer: Views expressed in the article are solely of the author’s own and do not necessarily belong to any of the Company. ***

--------------------------------------------------------------------------------------------------Author: Partha Das Sharma, B.Tech (Hons.) in Mining Engineering; E.mail:; Blog / Website: