4.1 Purpose. To establish Service policy concerning the safe and effective use of explosives.

4.2 Scope. This chapter covers the use of all explosives by Service personnel including cooperators, volunteers, and contractor personnel performing official work for the Service or on Service property.

4.3 Policy. The use of explosives is restricted to the operations for which there is no suitable alternative means for performance of the activity. In such cases, two-part explosives are the preferred type of explosive for blasting. When feasible, specific instructions for use of particular types of explosives will be added to this chapter in the form of an exhibit.

4.4 Authority.

A. The Occupational Safety and Health Act (P.L. 91-596-29)

B. Construction Safety Standards (29 CFR 1926)

C. General Industry Standards (29 CFR 1910.109)

D. Transportation Safety Act of 1974(49 U.S.C. 1801)
 
4.5 Responsibilities. These responsibilities supplement those found in 240 FW 1.

A. Contracting Officers shall ensure that any contracts for explosives operations contain the appropriate safety clauses.

B. Supervisors have the responsibility to:

(1) Ensure that provisions of this chapter are complied with.

(2) Ensure that the blaster is qualified by reason of training and experience to perform the particular blasting operation.

(3) To the degree possible, ensure that the blaster is not under the influence of alcohol or drugs which would interfere with the safe performance of the blasting operation.

(4) Ensure that a job hazard analysis (240 FW 2) is developed for all blasting operations.

C. Blasters are to operate in full accord with the provisions of this chapter. See also Appendix 1. The blaster is specifically responsible for the following:

(1) Complying with State and local laws and regulations which pertain to explosives.

(2) Using every reasonable precaution to ensure the safety of employees and the public.

4.6 Definitions.

A. Blast Area. The area in which explosives loading and blasting operations are being conducted.

B. Blasters. Persons qualified and authorized to use explosives for blasting purposes.

C. Blasting Agent. A material designed for blasting which has been tested in accordance with the tests contained in the Transportation Safety Act and found to be so insensitive that there is very little probability of accidental initiation to explosion or of transition from deflagration to detonation.

D. Blasting Cap. A metallic tube closed at one end, containing a charge of one or more detonating compounds, and designed for and capable of detonation from the sparks or flame from a safety fuse inserted and crimped into the open end.

E. Detonator. Any device containing a detonating charge that is used for initiating detonation in an explosive. The term includes, but is not limited to, electric blasting caps, blasting caps for use with safety fuses, and nonelectric blasting caps.

F. Detonating Cord. A flexible cord containing a center core of high explosive and used to detonate other cap sensitive explosives with which it is in contact.

G. Detonation. An explosive reaction.

H. Deflagration. An extremely rapid burning with intense heat or flame.

I. Electric Blasting Cap. Designed for and capable of detonation by means of an electric current.

J. Electric Blasting Circuitry.

(1) Bus Wire. An expendable wire connected to the leg wires of electric blasting caps.

(2) Connecting Wire. An insulated expendable wire used between electric blasting caps and the leading wire or between the bus wire and the leading wire.

(3) Leading Wire. An insulated wire connecting the electric power source and the electric blasting cap circuit.

K. Explosives. Any chemical compound mixture or device, the primary or common purpose of which is to function by explosion, including all material classified by the Department of Transportation as Class A, B, or C explosives.

(1) Class A. High explosives possessing a detonating capability such as dynamite, nitroglycerin, picric acid, lead azide, fulminate of mercury, black powder, blasting caps, and primers also known as boosters.

(2) Class B. Low explosives possessing a flammable capability such as propellant explosives, including some smokeless propellants.

(3) Class C. Certain types of manufactured articles which contain Class A or B explosives, or both, but in restricted quantities, such as fireworks.

L. High Explosives. An explosive material which can be caused to detonate by means of a blasting cap when unconfined. (For example, dynamite.)

M. Igloo. A reinforced concrete, arch type earth covered magazine.

N. Leg Wires. The two single wires or one duplex wire extending out from an electric blasting cap.

O. Low Explosives. Explosive material which can be caused to deflagrate when confined. (For example, black powder, safety fuses, igniters, or igniter cord.)

P. Magazine. Any building or structure, other than an explosive manufacturing building, used for the storage of explosives.

Q. Misfire. An explosive charge which fails to detonate.

R. Primer. A cartridge or container of explosives into which a detonator or detonating cord is inserted or attached.

S. Safety Fuse. A flexible cord containing an internal burning medium by which fire is conveyed at a continuous and uniform rate for the purpose of firing blasting caps.

T. Shelf Life. The length of time of storage during which an explosive material retains adequate performance characteristics.

U. Shunt. A short-circuiting device provided on the free ends of the leg wires of electrical blasting caps to protect them from accidental initiation by extraneous electricity.

V. Trunkline. The line of detonating cord that is used to connect and initiate other lines of detonating cord.

W. Two-part Explosive. A product consisting of two components which when mixed together form an explosive. The components can be a powder and liquid or a liquid and a solid.

4.7 Use of Explosives.

A. Blasting Operations

(1) Blasting operations are conducted only during daylight hours.

(2) Personnel are prohibited from carrying detonators or primers of any kind on their person.

(3) Flagmen are safely stationed on all roads which pass through the danger zone so as to stop traffic during blasting operations.

(4) A loud signal must be given before a charge is fired and ensuring that all surplus explosives are in a safe place and all people, vehicles, and equipment are at a safe distance from charge or under sufficient cover. (The requirement to give a loud signal before a charge is fired is abrogated during use of rocket net charges.) (See 241 FW 5).

(5) All persons are safely kept away from the charge for at least one hour if a misfire occurs.

(6) Personnel handling explosives must wear cotton clothing to reduce the build-up of static electricity and subsequent sparking.

B. Electric Blasting.

(1) The blasters must conduct a thorough survey to determine if sources of dangerous extraneous electricity are present in an electric blasting area. Dangerous currents must be eliminated or sufficiently minimized before any charges are set.

(2) The blaster is required to give consideration to the following electrical hazards: radar, radio transmitter, lightning, adjacent powerlines, dust storms, or other suspected sources.

(3) The blaster must use equipment or devices especially designed to light safety fuses while engaged in blasting operations.

(4) Electric blasting cap leg wires are kept short-circuited (shunted) until they are connected into the circuit.

(5) In any single blast, all blasting caps will be the same style or function and made by the same manufacturer.

(6) Connecting wires and lead wires will be insulated single solid wires and of sufficient current carrying capacity.

(7) The connections will be made from the charge to the blasting machine and the leading wires will remain shunted until the charge is fired. Only the blasters will make the leading wire connection.

(8) When testing circuits to charges, use only galvanometers equipped with a silver chloride cell especially designed for this purpose.

C. Safety Fuse Blasting.

(1) Safety fuse blasting is only used where sources of extraneous electricity make use of the electric blasting method dangerous.

(2) A test burn, not less than 0.91 meters (3 feet), will be made prior to any blasting operation.

(3) The use of sharply bent fuses will be prohibited.

(4) Required minimum fuse length is 76.2 centimeters (30 inches).

(5) Only a freshly cut fuse-end in the blasting cap and a cap crimper of approved design will be used.

D. Detonating Cord.

(1) When connecting a blasting cap to the detonating cord, the cap is taped securely along the side or the end of the cord with the end of the cap containing the explosive charge pointed in the direction in which the detonation is to proceed.

(2) Trunk line detonators will not be brought to the loading area nor attached to the detonating cord until everything else is in readiness for the blast.

E. Underwater Blasting.

(1) To avoid possible galvanic action, loading tubes and casings of dissimilar metals will not be used.

(2) Only water resistant blasting caps and detonating cord will be used for underwater blasting.

(3) No charge will be detonated while any watercraft underway is closer than 457.2 meters (1500 feet) to the blast area. Notification of a blast to persons aboard a moored or anchored craft within 457.2 meters (1500 feet) will be carried out before a charge is fired.

(4) No charge will be fired while any swimming or diving operations are in progress in the vicinity and persons are exposed to injury from the blast.

(5) To identify underwater misfires when more than one charge is placed, a float device will be attached to an element of each charge in such a manner that it is released by the firing.

4.8 Transportation of Explosives. In the transporting of explosives, vehicle operators will ensure that:

A. All Federal and State laws and regulations concerning transportation of explosives will be observed.

B. Vehicles will not be loaded beyond the rated hauling capacity of the vehicle. Explosives will be secured to prevent shifting of the load or dislodgment from the vehicle. Loads will not extend beyond the walls of the truck bed.

C. Vehicles used for the transportation of personnel and explosives are in good repair and mechanically sound.

D. Two fire extinguishers having a rating of 10-BC will be placed at strategic points in the vehicle accessible to the operator.

E. Vehicles containing explosives will not, under any circumstances, be taken into garages or repair shops, parked in congested areas, or stored overnight in public garages or similar buildings.

F. Extreme care will be exhibited during operations. Full stops will be made at approaches to all railroad crossings and main highways. When the way is clear, the vehicle will proceed with caution.

G. Prior to transporting explosives, all transport vehicles will be inspected to ensure that all electrical wiring is securely fastened to prevent short circuits.

H. When a motor vehicle containing hazardous materials is fueled, compliance with the following will be met:

(1) The engine will not be operating.

(2) One person will be in control of the fueling process at the point where the tank is filled.

I. No spark producing tools, oils, matches, firearms, electric storage batteries, flammable substances, acids, oxidizing, or corrosive compounds will be carried next to the explosives. No person will carry a flame or spark producing device on or within 7.62 meters (25 feet) of a motor vehicle which contains explosives.

J. In vehicles not having a closed body, the open bed will be covered by a flameproof and moistureproof cover to protect the explosives against sparks and moisture while transporting.

K. Vehicles used for the transportation of explosives will bear appropriate placards. The exterior markings or placards will be as follows:

(1) Class A or Class A and B. "Explosives A" will be in red letters on a white background.

(2) Class B. "Explosives B" will be in red letters on a white background.

(3) Oxidic Material (e.g., blasting agents). "Oxides" will be in yellow letters on a black background.

Such placards will be displayed at the front, rear, and on each side of the motor vehicle or trailer, or other cargo carrying body while it contains explosives. The front placard may be displayed on the front of either the truck, truck body, truck trailer, or the trailer. Any motor vehicle or other cargo-carrying body containing more than one kind of explosive as well as an oxidizing material, the aggregate gross weight of which totals 453.6 kilograms (1,000 lbs) or more, shall have a placard marked "Dangerous" in addition to a placard marked "Explosives A" or "Explosives B", as appropriate.

L. Blasting caps (including electric blasting caps) will not be transported in the vehicle or conveyance with other explosives unless the conditions of 49 CFR 177.835(g) can be met. The text of the exception and the references cited in the exception are included as Appendix 1 to this chapter.

M. Only original boxes or class II containers will be used when transporting detonators to the blasting area.

4.9 Storage of Explosives.

A. Magazines. There are five types of storage magazines based on the class of explosive material stored. A record of inventory must be maintained for each magazine. The inventory must remain current by the signing out of all explosives used and their immediate deletion from the record. The five types of magazines are listed below:

(1) Type 1. A permanent storage magazine for the storage of Class A, high explosive. Other classes may also be stored in the magazine. A Type 1 storage can be a permanent structure, a building, an igloo, a tunnel, or dugout. The storage magazine will be bullet resistant, fire resistant, weather resistant, theft resistant, and well ventilated.

(2) Type 2. A box, trailer, semitrailer, or other mobile facility.

(a) Type 2 outdoor magazines will be bullet resistant, fire-resistant, weather resistant, theft resistant, and ventilated. The magazine may be used to store high explosives as well as Class B and Class C explosives.

(b) Type 2 indoor magazines will be fire resistant and theft resistant. They need not be bullet resistant and weather resistant if the building in which they are stored provides protection from the weather and bullet penetration. No indoor magazines will be located in a residence or dwelling. The indoor storage of high explosives will not exceed a quantity of 22.6 kilograms (50 pounds). More than one indoor magazine may be located in the same building if the total quantity of explosive material will not exceed 22.6 kilograms (50 lbs). Indoor magazines can be constructed of wood and metal. Such magazines will be painted red and bear the lettering "Explosives - Keep Fire Away" on top, at least 76.2 millimeters (3 inches) high.

(3) Type 3. A portable outdoor magazine for the temporary storage of high explosives while attended. Other classes may be stored. The magazine may be less than 1 cubic yard in size, but must be bullet resistant, fire resistant, weather resistant, theft resistant, and well ventilated.

(4) Type 4. A permanent, portable or mobile structure such as a building, igloo, box, semi-trailer or other mobile container. The magazine may be used to store high explosives as well as Class B and Class C explosives.

(a) Type 4 outdoor magazines will be fire resistant, weather resistant, and theft resistant.

(b) Type 4 indoor magazines will comply with the requirements for Type 2 indoor magazines.

(5) Type 5. A magazine for storage of blasting agents. The magazines may be a building, an igloo, a tunnel, a dugout, a bin, a box, a trailer or semi-trailer, or other mobile magazine and must be theft resistant.

B. Storage Within Magazines. Storage of explosives within magazines will be in accordance with the following requirements.

(1) Magazines containing explosive materials will be opened and inspected at regular intervals to determine whether there has been an unauthorized entry or attempted entry into the magazines and whether there has been unauthorized removal of the magazines or its contents.

(2) Magazine doors will be locked, except during the time of placement and removal of stocks of explosives and during inspections.

(3) A copy of these requirements covering the operation of magazines will be posted on the magazine door.

(4) When any explosive is removed from a magazine for use, the oldest stock will be removed first.

(5) Similar grades and brands of explosives will be stored together in such manner that brand and grade marks show. All stocks will be stored and organized so they may be easily counted and checked.

(6) Containers of explosive materials will be arranged in a stable manner.

(7) Containers of explosive materials will be laid flat with the top side up.

(8) Open containers of explosive materials will be securely closed before returning to a magazine. Only fiberboard containers will be opened in the magazine. No container without a closed lid will be stored in the magazine.

(9) Wooden packages of explosive materials will not be unpacked or repacked in a magazine, within 15.2 meters (50 feet) of a magazine, or in close proximity to other explosive materials.

(10) Magazines will be used exclusively for storage of explosive materials, blasting materials, and blasting accessories.

(11) Magazine floors will be kept clean, dry, and free of grit, paper, empty used packages, and rubbish. Brooms and other cleaning utensils will not have any spark producing metal parts. Sweepings from floors of magazines will be disposed of in accordance with the instructions of the manufacturer.

(12) When explosive material has deteriorated to the point of being unstable or dangerous (see definition of shelf-life), the manufacturer will be notified and arrangements will be made to have the explosives destroyed in accordance with the manufacturer's instructions.

(13) When magazines need interior repairs, all explosives will be removed and the floors cleaned.

(14) When magazines need exterior repairs and there is a possibility of causing sparks or fire, the explosives will be removed from the magazine.

(15) Smoking, matches, open flames, spark-producing devices, and firearms (except firearms carried by authorized guards) will not be permitted inside or within 15.2 meters (50 feet) of magazines.

(16) Explosive materials removed from a magazine under repair will be placed in another magazine or placed a safe distance from the magazine, where they will be properly guarded and protected until repairs have been completed. Upon completion of the repairs, the explosive material will be promptly returned to the magazine.

(17) The land surrounding the magazines will be kept clear of brush, dried grass, leaves, and similar combustibles for a distance of at least 7.62 meters (25 feet).

(18) Combustible materials will not be stored within 15.2 meters (50 feet) of magazines.

(19) Explosive materials recovered from blasting misfires will be placed in a separate magazine until competent personnel have determined from the manufacturer the method of disposal. Caps and electric blasting caps recovered from blasting misfires will not be reused. Such explosive materials will be disposed of in the manner recommended by the manufacturer.

(20) Property upon which Type 1 magazines are located and property upon which all outdoor magazines of Types 2, 4, and 5 are located will be posted with signs reading, "Explosives - Keep Off." Such signs will be located so that a bullet that is shot at the sign will not hit the magazine.

(21) Blasting caps, electric blasting caps, detonating primers, and primer cartridges will not be stored in the same magazine with other explosives.

C. Location. Storage magazines are to be located beyond minimum distances from inhabited buildings, passenger railways, public highways, and other storage magazines in which explosive materials are stored as specified in the American Table of Distances for Storage of Explosives (see Appendix 2).

4.10 Station Safety Plan. Whenever explosives are used or stored at a facility, the station safety plan will include specific instructions concerning the storage and use of such explosives and the safeguards to be taken in an emergency situation. With regard to any fire suppression activities, such activities will be halted and the facility evacuated whenever the existing fire threatens to come in contact with explosive materials.