Ammonium Nitrate Storage Facilities Regulations (C.R.C., c. 1145)

Regulations are current to 2014-10-15

Ammonium Nitrate Storage Facilities Regulations

C.R.C., c. 1145

CANADA TRANSPORTATION ACT

Regulations Respecting the Design, Location, Construction, Operation and Maintenance of Storage Facilities for Ammonium Nitrate and Ammonium Nitrate Mixed Fertilizers

SHORT TITLE

 These Regulations may be cited as the Ammonium Nitrate Storage Facilities Regulations.

INTERPRETATION

 In these Regulations,

“ammonium nitrate”

“ammonium nitrate” means the chemical compound NH4 NO3 in granular, prilled, flake, crystalline or other solid form; (nitrate d’ammonium)

“ammonium nitrate mixed fertilizer”

“ammonium nitrate mixed fertilizer” means a mixture consisting of ammonium nitrate and other fertilizer or inert substances and intended for use as a fertilizer; (engrais mélangés contenant du nitrate d’ammonium)

“capacity of a storage facility”

“capacity of a storage facility” means the maximum weight of ammonium nitrate or ammonium nitrate mixed fertilizer which the applicant, in accordance with the requirements of Part I, declares he will store therein; (capacité d’une installation d’emmagasinage)

“Commission”

“Commission” means the Canadian Transport Commission; (Commission)

“dangerous commodity”

“dangerous commodity” means any substance subject to the Regulations for the Transportation of Dangerous Commodities by Rail as approved by General Order O-29 and amendments thereto, or subject to any other regulations or order made by the Commission to control its hazard; (marchandise dangereuse)

“main track”

“main track” is a track extending through yards and between stations where trains are operated by timetable, train order, block signals, or some other method of control approved by the Commission; (voie ferrée principale)

“National Building Code of Canada”

“National Building Code of Canada” means the building code of that name which is published by the National Research Council; except as may otherwise be prescribed in these Regulations, building classifications, types of construction and fire separations shall be in accordance with that Code; (Code national du bâtiment au Canada)

“on-site building or structure”

“on-site building or structure” means a building or structure occupying the same site as the storage facility and is used exclusively by the company or person that operates the storage facility; (bâtiment ou ouvrage sur l’emplacement)

“ordinary location”

“ordinary location” means a location in which electrical equipment, under normal conditions of use, is not unduly exposed to damage from mechanical causes, excessive dust, moisture, extreme temperatures or corrosive, flammable or explosive atmospheres; (emplacement ordinaire)

“owning or operating company”

“owning or operating company” means the person or company owning or operating the storage facility; (compagnie propriétaire ou exploitante)

“railway right-of-way”

“railway right-of-way” means lands that are owned or leased by a railway, are contiguous to that railway’s tracks and are required for railway purposes; (emprise du chemin de fer)

“railway station”

“railway station” means any location where passenger or freight trains may stop in accordance with the current railway timetable; (gare de chemin de fer)

“railway station-dwelling”

“railway station-dwelling” means a railway station, of which a part is used as a dwelling; (gare-habitation)

“serving track”

“serving track” means the track serving the storage facility and upon which railway cars are located for loading or unloading purposes; (voie de desserte)

“shall”

“shall” is used to indicate mandatory provisions; (le futur)

“should”

“should” is used to indicate a recommendation; (le conditionnel)

“storage facility”

“storage facility” means a warehouse or other enclosure used for the storage of ammonium nitrate or ammonium nitrate mixed fertilizer. (installation d’emmagasinage)

APPLICATION

 Subject to any licence law or other law or by-law of any province or municipality lawfully enacted with regard to storage facilities for ammonium nitrate or ammonium nitrate mixed fertilizers, the Commission, for the protection of property and the protection, safety, accommodation and comfort of the public and of the employees of the railway company and users of the railway and railway property, makes these Regulations applying to  storage facilities for ammonium nitrate and ammonium nitrate mixed fertilizers located on the right-of-way owned or leased by any railway company subject to the jurisdiction of the Canadian Transport Commission.

 These Regulations do not apply to

  • (a) storage facilities which at no time will contain more than 3,000 pounds of ammonium nitrate or ammonium nitrate mixed fertilizers;

  • (b) nitro carbo nitrates or other ammonium nitrate blasting agents; the preparation, storage or use of such blasting agents or similar mixtures in or contiguous to an ammonium nitrate or ammonium nitrate mixed fertilizer storage facility is prohibited; and

  • (c) ammonium nitrate mixed fertilizers containing less than 60 per cent ammonium nitrate by weight if they do not contain iron oxide, chromic oxide, inorganic salts of chromium, copper or manganese, powdered metals, sulphur, potassium chloride or any other ingredient in quantities which will appreciably sensitize or otherwise increase the hazard of ammonium nitrate.

PART IAPPLICATIONS FOR APPROVAL

  •  (1) Except as provided in subsections (2) and (3), no storage facility with a capacity exceeding 200 tons, including any addition thereto, shall be constructed without an order of the Commission issued upon an application prepared and submitted in accordance with the requirements of sections 7 to 11.

  • (2) Notwithstanding subsection (1), such a storage facility may be constructed without an order of the Commission if the prior written consent of the Director of Operation is obtained; however, such a storage facility shall not be used until it is approved by an order of the Commission issued upon an application prepared and submitted in accordance with sections 7 to 11.

  • (3) Notwithstanding subsection (1), such a facility completed prior to October 30, 1965 may be used until October 30, 1966 without an order of the Commission, if it is operated and maintained in accordance with the requirements of Part IV; but it shall not be used after October 30, 1966 without an order of the Commission made upon an application prepared and submitted in accordance with sections 7 to 11.

  •  (1) Except as provided in subsections (2) and (3), a storage facility with a capacity not exceeding 200 tons, including any addition thereto, shall not be constructed without the written consent of the Director of Operation, granted upon an application prepared in accordance with sections 8 to 11 and submitted in duplicate to him.

  • (2) Except as provided in subsection (3) and notwithstanding subsection (1), such a storage facility completed prior to October 30, 1965 may be used until October 30, 1966 without the consent of the Director of Operation, if it is operated and maintained in accordance with the requirements of Part IV; but it shall not be used after October 30, 1966 until consent to do so is obtained in the manner prescribed in subsection (1).

  • (3) Notwithstanding subsections (1) and (2), decisions of the Director of Operation with respect to those requirements may be appealed to the Commission.

  •  (1) Applications for the approval of the Commission to construct a storage facility, as prescribed in section 5, shall be submitted through the railway company concerned to the Secretary of the Commission.

  • (2) Such applications shall be accompanied by four copies of all drawings, prepared in accordance with sections 8 to 11.

  •  (1) A plot plan showing the location of the storage facility in relation to the other structures and boundary lines referred to in section 10, shall be drawn to a minimum scale of one inch to 100 feet.

  • (2) If the plot plan prescribed in subsection (1) does not provide a clear representation of the storage facility in relation to other structures on the same site, a plan of the on-site structures drawn to a minimum scale of one inch to 50 feet shall be provided.

 All drawings and data sheets shall be dated, bear an identification number and the name of the applicant. The drawings and data sheets shall be signed, preferably by the Chief Engineer or other official of the company responsible for either their preparation or submission.

 The plan shall show by dimension lines the location of the storage facility in relation to the buildings, structures and property lines referred to in the following paragraphs and if there are no buildings within the distances specified herein, a statement to this effect shall appear in the drawing notes:

  • (a) the gauge side of the nearest rail of the track serving the facility;

  • (b) the gauge side of the nearest rail of any main track or any track other than a track serving the facility and located within 20 feet of the storage facility;

  • (c) any building or other structure mentioned in paragraphs 12(a) to (d);

  • (d) boundary lines of the leased property upon which the storage facility is located;

  • (e) railway right-of-way boundaries;

  • (f) all structures located on the same site as the storage facility; and

  • (g) nearest fire hydrant or other source of water available for fire fighting purposes; indicate pressure and gallons per minute of water available at the hydrant nozzle and the approximate distance to the nearest fire department.

 Applications will only be considered if the following information is provided in the drawing notes or legend or in data sheets or letters attached thereto:

  • (a) evidence that the Provincial Fire Marshal, Fire Commissioner or other local fire authority having jurisdiction in the area has no objection to the proposed storage facility; such evidence may be provided by the appropriate authority either by signing the plan or in a letter addressed to the owning or operating company;

  • (b) contents of the storage facility and ancillary buildings and the approximate quantity of each material in storage;

  • (c) size, general design features and materials of construction of the storage facility and ancillary buildings;

  • (d) type and size of fork lift truck, front end loader, or other motive power to be used in the storage facility;

  • (e) type and size of heating unit, if any, in the storage facility or an attached building;

  • (f) location of the storage facility by reference to the railway company serving the site, the railway subdivision, the railway mileage and the name of the hamlet, village, town or city in which the storage facility is located; and

  • (g) a statement shall appear in the drawing notes to the effect that the proposed facility complies in all respects with these Regulations, unless there are exceptions, in which case the exceptions shall be listed.

 Where the Commission has issued an order pursuant to subsection 5(1) relating to the construction of a storage facility, a copy of each drawing referred to in subsection 7(2) shall be kept by the railway company for the life of the storage facility and retained for at least two years thereafter.

  • SOR/85-470, s. 1.

PART IIDISTANCES

 Except as provided in sections 13 and 14, the horizontal distance between a storage facility and the nearest point of another building, structure or property line, should not be less than

  • (a) 300 feet from any school, hospital, hotel, motel, church, theatre, auditorium, sports arena, multi-store shopping centre, apartment or other similar multi-unit residential building, office building or department store or merchandise building of more than one storey in height or any other similar structure used for assembly, institutional, residential, business, personal service, or mercantile purposes, or any building considered by the Commission to belong to this category;

  • (b) 150 feet from a single family dwelling, railway passenger station, railway station-dwelling, office building or department store or merchandise building or restaurant of one storey in height, or any other similar structure used for housing, business, personal service, or mercantile purposes, or any other building considered by the Commission to belong to this category;

  • (c) 100 feet from any factory, railway shop or other building used primarily for manufacturing, processing or for maintenance or repair work, or from an adjoining office building associated with these buildings, except that this distance should not be less than 50 feet if the capacity of the storage facility does not exceed 200 tons;

  • (d) 100 feet from any railway freight station, warehouse, storage tank or any other storage or transfer facility used for a combustible or dangerous commodity or from an adjoining office building associated with these buildings, except that this distance should not be less than 50 feet if the capacity of the storage facility does not exceed 200 tons;

  • (e) the following distances from the nearest point of the line of an adjoining property which has been or may be built upon and which is owned or leased by any person or company other than the owner of the storage facility:

    • (i) not less than 25 feet if the capacity of the storage facility does not exceed 200 tons,

    • (ii) not less than 50 feet if the capacity of the storage facility exceeds 200 tons, unless it is constructed of non-combustible materials as provided for by subparagraph (iii) or the adjoining property is occupied by another ammonium nitrate storage facility as provided for by subparagraph (iv),

    • (iii) not less than 25 feet if the storage facility referred to in subparagraph (ii) is of non-combustible construction and has a fire separation of not less than 1 1/2 hours on the exposed side,

    • (iv) not less than 25 feet if the property adjoining the property referred to in subparagraph (ii) is occupied by another ammonium nitrate storage facility approved in accordance with these Regulations and if there are no other buildings between the two storage facilities;

  • (f) 20 feet from the gauge side of the nearest rail of a main track or any track other than a track serving the storage facility; and

  • (g) the distances prescribed in Schedule I from the gauge side of the nearest rail of the track serving the storage facility.

 Notwithstanding section 12, greater safety distances may be imposed on storage facilities located within densely populated areas or other areas considered by the Commission to be of special hazard.

  •  (1) Notwithstanding section 12, and except as provided in subsection (2), the horizontal distance between a storage facility not exceeding a capacity of 200 tons and another on-site structure which is used only for storage purposes and which does not contain a dangerous commodity should not be less than 10 feet.

  • (2) Notwithstanding section 12 and subsection (1), lesser distances may be authorized at the discretion of the Commission between a storage facility and other on-site structures.

PART IIIDESIGN AND CONSTRUCTION OF STORAGE FACILITIES

 Unless specifically approved by an Order of the Commission,

  • (a) a storage facility shall not be more than one storey in height, except as may be necessary to house an elevator or similar equipment, and it shall not be erected over a basement;

  • (b) bulk storage bins shall not exceed 40 feet in height, unless they are constructed of non-combustible material.

  •  (1) It is recommended that non-combustible construction be used for storage facilities subject to these Regulations.

  • (2) If the floor or any other part of a storage facility in contact with ammonium nitrate or ammonium nitrate mixed fertilizer is fabricated from a combustible material, it shall be protected against ammonium nitrate impregnation by a plastic sheet or a suitable coating such as polyurethane or epoxy paint.

  • (3) Parts of a storage facility in contact with ammonium nitrate and fabricated from metal such as zinc, lead, copper or other metal, which will react with ammonium nitrate, shall be protected by a suitable coating.

  •  (1) Except as provided in subsections (2) to (4), the floor of a storage facility shall not contain drains, traps, pits or other depressions in which molten ammonium nitrate may become confined in the event of a fire.

  • (2) Notwithstanding subsection (1), elevator pits and conveyor trenches may be installed in the floor of a storage facility if molten ammonium nitrate is prevented from flowing into them by curbs or other construction features acceptable to the Commission, or there are extenuating circumstances that, in the opinion of the Commission, justify or minimize the hazard of an opening in the floor.

  • (3) Ammonium nitrate or mixed fertilizers containing 60 per cent or more ammonium nitrate shall not be stored in bins or piles that are contiguous to an elevator pit or conveyor trench where it is practical to store them in a location separated from the floor openings referred to in subsection (1) by bins or piles containing non-combustible and non-hazardous materials.

  • (4) Trenches shall not be constructed under railway tracks unless approval to do so has been obtained from the Commission. Applications for this approval shall be submitted through the railway company concerned.

 All storage facilities, except those that are self-ventilating under fire conditions, shall be ventilated with permanently open ventilators to assist in the dissipation of the heat and gases produced by the decomposition of ammonium nitrate in a fire.

  •  (1) Except as provided in subsection (2), all electrical wiring, lighting or equipment inside a storage facility or attached to it shall comply with the requirements of the Canadian Electrical Code, (CSA Standard C22.1 — 1962 and amendments thereto), as prescribed for ordinary locations. A storage facility containing bagged ammonium nitrate or ammonium nitrate mixed fertilizer and no other electrical hazard is designated an “ordinary location”.

  • (2) All parts of an electrical system not installed in ordinary locations shall comply with those requirements of the Canadian Electrical Code applicable to the particular hazards present. A storage facility containing bulk ammonium nitrate or ammonium nitrate mixed fertilizer and no other electrical hazard is designated a Class II Division II location.

 The design, construction and maintenance of a storage facility shall be such as to prevent the normal ingress of rain and ground water.

PART IVGENERAL

  •  (1) Except as provided in subsection (2), smoking, or the use of heaters, welding or other equipment with an open flame or an exposed electric element, inside a storage facility is prohibited.

  • (2) Notwithstanding subsection (1), welding or cutting repairs may be made inside a storage facility to metal equipment or components of the storage facility if the broken part cannot be removed for repair out-of-doors and the following precautions are taken:

    • (a) all ammonium nitrate and other dangerous or combustible materials stored within 10 feet of the repair site shall be removed;

    • (b) the welding or cutting operation shall be completely screened to prevent sparks from leaving the enclosed clean area and if the floor in this area is constructed of wood or other combustible material, its exposed surface shall be drenched with water or protected against sparks by a flame-proof tarpaulin or a metal sheet;

    • (c) a fire extinguisher as prescribed in section 24 and a water hose, or a static supply of not less than 45 gallons of water, shall be available at the repair site; and

    • (d) the operation shall be under the supervision of a qualified and responsible person who shall remain at the repair site for at least 30 minutes after the completion of repair operations.

  • (3) If it is necessary to heat a storage facility, it is recommended that the heat be supplied by an electric heater which complies with section 19 or by low pressure steam, hot water or other enclosed heat transfer media with the heat source located in a detached building at least 10 feet from the storage facility, and heating systems which do not comply with this recommendation shall be approved by the Commission.

  • (4) Heating equipment shall be designed and installed in accordance with the National Building Code of Canada, except that no part of the equipment with an open flame or other source of ignition shall be installed in the storage area.

 A weatherproof sign bearing the words “AMMONIUM NITRATE” and “NO SMOKING OR OPEN FLAMES”, or other wording acceptable to the Commission, in block letters at least two inches high on a white or a light coloured background shall be posted in a conspicuous place near each entrance to the storage facility.

  •  (1) Except as provided in subsections (2) and (3), the storage or use of explosives, corrosive liquids, radioactive materials, poisons, flammable solids, flammable liquids, liquefied petroleum or other flammable or compressed gases, sulphur, finely divided metals or any combustible or dangerous commodity is prohibited in or contiguous to a storage facility unless such storage or use is expressly approved by the Commission.

  • (2) Notwithstanding subsection (1), approval of the Commission is not required to store the following substances or items in a storage facility:

    • (a) ammonium sulphate, ammonium phosphates, ammonium phosphate-sulphate mixtures, calcium metaphosphate, potassium phosphates, potassium chloride, potassium sulphate, phosphate rock, sulphate of potash-magnesia, superphosphates, diatomaceous earth, dolomite, gypsum, kaolin, limestone, farm equipment or machinery with empty fuel tanks, spare parts, hardware, baling twine, or securely packaged herbicides, pesticides and fungicides;

    • (b) urea, urea compounds or bagged grain or grain products if they are separated from bagged ammonium nitrate or ammonium nitrate mixed fertilizer by a wall with a fire resistance of at least one hour or by a distance of not less than 30 feet or by any other method acceptable to the Commission that will prevent mixing of the segregated materials under fire conditions, and the separating wall shall extend above the highest adjacent pile or to the top plate of the outside wall, whichever is the higher.

  • (3) Notwithstanding subsection (1), equipment or vehicles powered by internal combustion engines employing a flammable fuel may be used in a storage facility if their exhausts are equipped with spark arrestor devices, but they shall not be fuelled, repaired or maintained in the storage facility, and except as provided in subsection (4), they shall not be parked in a storage facility overnight or during other periods when the storage facility is unattended for more than four hours.

  • (4) Notwithstanding subsection (3), vehicles and portable equipment powered by engines using a flammable fuel, and used inside the storage facility, may be parked in that facility if

    • (a) the parking area is reserved exclusively for parking of the aforesaid equipment or vehicle;

    • (b) the parking area is separated on all sides from the rest of the storage facility by an enclosure, and this enclosure is of non-combustible construction, and has a fire separation of not less than two hours; masonry walls constructed from hollow core concrete blocks not less than eight inches thick are considered to satisfy this requirement; the door shall be tightly closed during the parking period;

    • (c) no wall of the parking enclosure is less than 30 inches from the nearest pile or bin of ammonium nitrate or ammonium nitrate mixed fertilizer; and

    • (d) the floor of the parking enclosure is of solid concrete not less than six inches thick.

  •  (1) Except as provided in subsection (2), at least one 20-pound or two 10-pound ABC dry chemical fire extinguishers or the equivalent first aid fire protection shall be readily available on the storage premises for fighting small fires involving combustible materials or electrical equipment, but only water shall be used for extinguishing ammonium nitrate fires.

  • (2) Notwithstanding subsection (1), only one 10-pound ABC dry chemical fire extinguisher or its equivalent is required for a storage facility with a floor area not exceeding 1,500 square feet.

  • (3) Except as provided in subsection (4), a storage facility with a floor area exceeding 1,500 square feet shall be protected by at least one standard fire hydrant which should be located not more than 500 feet from the storage facility and should be capable of providing not less than 500 gallons of water per minute at 45 psi.

  • (4) The Commission may waive the requirements of subsection (3) if a supply of water is not available and if in its discretion the storage facility is sufficiently isolated or there are other factors which compensate for the absence of fire hydrant protection.

  •  (1) Except as provided  in subsection (2), bagged ammonium nitrate or ammonium nitrate mixed fertilizers shall be piled at least 12 inches and preferably not less than 30 inches from any wall or partition of the storage facility, and the top of the pile shall be at least three feet below the roof and supporting roof members.

  • (2) Notwithstanding subsection (1), bagged ammonium nitrate or ammonium nitrate mixed fertilizer may be piled less than 12 inches from a wall or partition if the total approved capacity of the storage facility does not exceed 200 tons and none of the bags is in contact with the wall or partition.

  • (3) The width of a pile of bagged ammonium nitrate or ammonium nitrate mixed fertilizer in a storage facility of a total floor area exceeding 1,500 square feet shall not exceed 20 feet and, unless the storage facility is of non-combustible construction or is protected by an automatic sprinkler system, the length of a pile shall not exceed 50 feet.

  • (4) Piles as prescribed in subsection (3) shall be separated by aisles at least three feet wide, and at least one main or service aisle not less than four feet wide should be provided.

  • (5) Piles or bins should be sized and arranged so that the materials which have been in storage for the longest period are used first.

  • (6) Ammonium nitrate or ammonium nitrate mixed fertilizers in bags or bulk shall not be stored in contact with hot pipes, conduits, ducts, light bulbs or any other object with a surface temperature exceeding 100°F and should be stored at least 30 inches from such objects.

 Ammonium nitrate or ammonium nitrate mixed fertilizers containing residual process heat and having a temperature exceeding 130°F shall not be accepted for storage in a storage facility subject to these Regulations.

 The storage facility should be protected against lightning in accordance with the recommendations contained in the Canadian Standards Association Code B-72 or the applicable provincial code.

 The storage facility and the area surrounding it shall be maintained in a clean and tidy condition at all times; grass and weed growth within 25 feet of the storage facility shall not be permitted to exceed six inches in height and it is recommended that the area within six feet of the storage facility be bare ground or pavement; spilled material from punctured or torn bags or from other sources shall be cleaned up promptly.

 All storage facilities subject to the requirements of these Regulations may be inspected at any time by any authorized officer of the Commission.

 Every fire, explosion, or similar accident involving a storage facility shall be reported by telegram by the owner, operator or employee in charge of the storage facility, within 12 hours of such an accident, to the Director of Operation of the Canadian Transport Commission, Ottawa, and to the railway company concerned, and the telegraphic report shall be followed by a detailed report not later than 30 days after the accident.

 Violations of any of these Regulations are subject to such penalty as may be provided in the Railway Act.

 The principal hazards associated with the storage of ammonium nitrate are discussed in Schedule II.

SCHEDULE I(s. 12)

MINIMUM CLEARANCE DISTANCES MEASURED HORIZONTALLY BETWEEN THE TRACK SIDE OF A LOADING OR UNLOADING RACK OR TERMINAL AND THE GAUGE SIDE OF THE NEAREST RAIL OF ANY TRACK

Minimum Distance from gauge side of nearest rail
STRAIGHT TRACK
  • (a) That portion of a rack or structure more than 4 feet above the top of the rail

6 feet
  • (b) Except as provided in (c), that portion of a rack or structure 4 feet or less above the top of the rail

3 feet 7 3/4 inchesFootnote for

MINIMUM CLEARANCE DISTANCES MEASURED HORIZONTALLY BETWEEN THE TRACK SIDE OF A LOADING OR UNLOADING RACK OR TERMINAL AND THE GAUGE SIDE OF THE NEAREST RAIL OF ANY TRACK

*
  • (c) Loading, unloading racks or terminals of an overall height of 4 feet or less above the top of the rail

6 feet
CURVED TRACK
All distances prescribed for straight track shall be increased by 1 inch per degree of track curvature.
  • Note: 
    Less than standard clearances are known as restricted clearances. Restricted clearances shall be approved in accordance with the requirements of the Railway Clearance Regulations.

SCHEDULE II(s. 32)STORAGE HAZARDS OF AMMONIUM NITRATE

  • 1. It is believed that compliance with these Regulations will provide a high degree of safety in the storage of ammonium nitrate. Effective implementation of these requirements is most likely to be realized if the persons involved in the storage operations have a good knowledge and understanding of the properties and hazards of ammonium nitrate.

  • 2. The principal properties and hazards of ammonium nitrate are as follows:

    • (a) ammonium nitrate is an oxidizing material that, at elevated temperatures, will support the combustion of materials such as wood, paper, fuel oil and sulphur; but self-sustaining burning reactions are not usually obtained unless more than one per cent of combustible material is present;

    • (b) ammonium nitrate undergoes thermal decomposition when heated to temperatures above about 150°F and, under certain conditions, some of which are mentioned below, this decomposition may become dangerous; because ammonium nitrate is usually stored in very large quantities, it has the potential to escalate an ordinary fire into an event approaching disaster proportions and for this reason, even a very small probability of occurrence cannot be ignored;

    • (c) it is important that ammonium nitrate be adequately separated from combustible materials and that the risk of fire be kept at as low a level as practicable;

    • (d) mixed fertilizers containing not more than 60 per cent ammonium nitrate as the only oxidizing material, with the balance as inert material, are not usually considered to be either a fire or an explosion hazard in storage; but certain additives or diluents may render even mixed fertilizers as hazardous or more hazardous than pure ammonium nitrate; for this reason, the exemption of a mixed fertilizer from compliance with the requirements of the Commission will depend on the nature and quantities of the ingredients in the mixture;

    • (e) it has been demonstrated in laboratory experiments that when the decomposition gases are sufficiently confined, they will accelerate or otherwise promote the decomposition reaction; this confinement may be obtained by accident, such as by the collapse of a building;

    • (f) two of the decomposition gases, nitrous oxide and ammonia, when mixed with certain other gases such as carbon monoxide, are capable of exploding; such explosions may be of sufficient power to detonate the ammonium nitrate;

    • (g) provisions should be made in the design of storage buildings for adequate ventilation in the event of a fire;

    • (h) small quantities of iron oxide, chromic oxide and some of the inorganic salts of chromium, copper and manganese are known to enhance or activate the decomposition of ammonium nitrate; it has also been determined that some of the powdered metals such as zinc, magnesium, tin and copper will react with ammonium nitrate to form compounds which are sensitive to impact;

    • (i) fortunately, the precautions which must be taken to keep the storage hazards of fertilizer grade ammonium nitrate and ammonium nitrate mixed fertilizers within acceptable bounds are relatively simple; it is believed that compliance with the storage requirements of the Commission will sufficiently reduce the explosion hazard of ammonium nitrate so that this hazard need not be allowed for in the safety distance requirements;

    • (j) water is the only known satisfactory extinguishing agent for an ammonium nitrate fire and should be available near the storage facility in large quantities for immediate use;

    • (k) as an ammonium nitrate fire progresses, large quantities of very toxic gases are evolved which make it impossible for fire fighters to remain in the vicinity of the fire, unless they are equipped with self-contained breathing apparatus;

    • (l) all occupied buildings within the vicinity of an ammonium nitrate fire should be evacuated promptly; and

    • (m) for further information on this subject, the reader is referred to the National Fire Protection Association, 60 Batterymarch Street, Boston, Massachusetts, 02110, or to the nearest ammonium nitrate producer.