286 

§ 1910.108 29 CFR Ch. XVII (7–1–13 Edition) 

this equipment in the coating area 

shall not exceed 150 °F. The high voltage circuits shall be so designed as to 

not produce a spark of sufficient intensity to ignite any powder-air mixtures 

nor result in appreciable shock hazard 

upon coming in contact with a grounded object under normal operating conditions. 

(ii) Transformers, powerpacks, control apparatus, and all other electrical 

portions of the equipment, with the exception of the charging electrodes and 

their connections to the power supply 

shall be located outside of the powder 

coating area or shall otherwise conform to the requirements of paragraph 

(l)(1) of this section. 

(iii) All electrically conductive objects within the charging influence of 

the electrodes shall be adequately 

grounded. The powder coating equipment shall carry a prominent, permanently installed warning regarding the 

necessity for grounding these objects. 

(iv) Objects being coated shall be 

maintained in contact with the conveyor or other support in order to insure proper grounding. Hangers shall 

be regularly cleaned to insure effective 

contact and areas of contact shall be 

sharp points or knife edges where possible. 

(v) The electrical equipment shall be 

so interlocked with the ventilation system that the equipment cannot be operated unless the ventilation fans are 

in operation. 

(m) Organic peroxides and dual component coatings—(1) Conformance. All 

spraying operations involving the use 

of organic peroxides and other dual 

component coatings shall be conducted 

in approved sprinklered spray booths 

meeting the requirements of this section. 

(2) Smoking. Smoking shall be prohibited and ‘‘No Smoking’’ signs shall be 

prominently displayed and only nonsparking tools shall be used in any area 

where organic peroxides are stored, 

mixed or applied. 

(n) Scope. This section applies to 

flammable and combustible finishing 

materials when applied as a spray by 

compressed air, ‘‘airless’’ or ‘‘hydraulic 

atomization,’’ steam, electrostatic 

methods, or by any other means in continuous or intermittent processes. The 

section also covers the application of 

combustible powders by powder spray 

guns, electrostatic powder spray guns, 

fluidized beds, or electrostatic fluidized 

beds. The section does not apply to 

outdoor spray application of buildings, 

tanks, or other similar structures, nor 

to small portable spraying apparatus 

not used repeatedly in the same location. 

[39 FR 23502, June 27, 1974, as amended at 45 

FR 60704, Sept. 12, 1980; 49 FR 5322, Feb. 10, 

1984; 53 FR 12121, Apr. 12, 1988; 61 FR 9237, 

Mar. 7, 1996; 72 FR 71069, Dec. 14, 2007; 77 FR 

17776, Mar. 26, 2012] 

§ 1910.108 [Reserved] 

§ 1910.109 Explosives and blasting 

agents. 

(a) Definitions applicable to this section—(1) Blasting agent. Blasting 

agent—any material or mixture, consisting of a fuel and oxidizer, intended 

for blasting, not otherwise classified as 

an explosive and in which none of the 

ingredients are classified as an explosive, provided that the finished product, as mixed and packaged for use or 

shipment, cannot be detonated by 

means of a No. 8 test blasting cap when 

unconfined. 

(2) Explosive-actuated power devices. 

Explosive-actuated power device—any 

tool or special mechanized device 

which is actuated by explosives, but 

not including propellant-actuated 

power devices. Examples of explosiveactuated power devices are jet tappers 

and jet perforators. 

(3) Explosive. Explosive—any chemical compound, mixture, or device, the 

primary or common purpose of which is 

to function by explosion, i.e., with substantially instantaneous release of gas 

and heat, unless such compound, mixture, or device is otherwise specifically 

classified by the U.S. Department of 

Transportation; see 49 CFR chapter I. 

The term ‘‘explosives’’ shall include all 

material which is classified as Class A, 

Class B, and Class C explosives by the 

U.S. Department of Transportation, 

and includes, but is not limited to dynamite, black powder, pellet powders, 

initiating explosives, blasting caps, 

electric blasting caps, safety fuse, fuse 

lighters, fuse igniters, squibs, cordeau 

287 

Occupational Safety and Health Admin., Labor § 1910.109 

detonant fuse, instantaneous fuse, igniter cord, igniters, small arms ammunition, small arms ammunition primers, smokeless propellant, cartridges 

for propellant-actuated power devices, 

and cartridges for industrial guns. 

Commercial explosives are those explosives which are intended to be used in 

commercial or industrial operations. 

NOTE 1: Classification of explosives is described by the U.S. Department of Transportation as follows (see 49 CFR chapter I): 

(i) Class A explosives. Possessing, detonating, or otherwise maximum hazard; such as dynamite, nitroglycerin, 

picric acid, lead azide, fulminate of 

mercury, black powder, blasting caps, 

and detonating primers. 

(ii) Class B explosives. Possessing 

flammable hazard, such as propellant 

explosives (including some smokeless 

propellants), photographic flash powders, and some special fireworks. 

(iii) Class C explosives. Includes certain types of manufactured articles 

which contain Class A or Class B explosives, or both, as components but in restricted quantities. 

(iv) Forbidden or not acceptable explosives. Explosives which are forbidden or 

not acceptable for transportation by 

common carriers by rail freight, rail 

express, highway, or water in accordance with the regulations of the U.S. 

Department of Transportation, 49 CFR 

chapter I. 

(4) Highway. Highway—any public 

street, public alley, or public road. 

(5) [Reserved] 

(6) Magazine. Magazine—any building 

or structure, other than an explosives 

manufacturing building, used for the 

storage of explosives. 

(7) Motor vehicle. Motor vehicle—any 

self-propelled vehicle, truck, tractor, 

semitrailer, or truck-full trailers used 

for the transportation of freight over 

public highways. 

(8) Propellant-actuated power devices. 

Propellant-actuated power devices— 

any tool or special mechanized device 

or gas generator system which is actuated by a smokeless propellant or 

which releases and directs work 

through a smokeless propellant charge. 

(9) [Reserved] 

(10) Pyrotechnics. Pyrotechnics—any 

combustible or explosive compositions 

or manufactured articles designed and 

prepared for the purpose of producing 

audible or visible effects which are 

commonly referred to as fireworks. 

(11) [Reserved] 

(12) Semiconductive hose. 

Semiconductive hose—a hose with an 

electrical resistance high enough to 

limit flow of stray electric currents to 

safe levels, yet not so high as to prevent drainage of static electric charges 

to ground; hose of not more than 2 

megohms resistance over its entire 

length and of not less than 5,000 ohms 

per foot meets the requirement. 

(13) Small arms ammunition. Small 

arms ammunition—any shotgun, rifle, 

pistol, or revolver cartridge, and cartridges for propellant-actuated power 

devices and industrial guns. Militarytype ammunition containing explosivebursting charges, incendiary, tracer, 

spotting, or pyrotechnic projectiles is 

excluded from this definition. 

(14) Small arms ammunition primers. 

Small arms ammunition primers— 

small percussion-sensitive explosive 

charges, encased in a cup, used to ignite propellant powder. 

(15) Smokeless propellants. Smokeless 

propellants—solid propellants, commonly called smokeless powders in the 

trade, used in small arms ammunition, 

cannon, rockets, propellant-actuated 

power devices, etc. 

(16) Special industrial explosives devices. Special industrial explosives devices—explosive-actuated power devices and propellant-actuated power 

devices. 

(17) Special industrial explosives materials. Special industrial explosives materials—shaped materials and sheet 

forms and various other extrusions, 

pellets, and packages of high explosives, which include dynamite, trinitrotoluene (TNT), pentaerythritol 

tetranitrate (PETN), hexahydro-1,3,5- 

trinitro-s-triazine (RDX), and other 

similar compounds used for high-energy-rate forming, expanding, and 

shaping in metal fabrication, and for 

dismemberment and quick reduction of 

scrap metal. 

(18) Water gels or slurry explosives. 

These comprise a wide variety of materials used for blasting. They all contain 

substantial proportions of water and 

high proportions of ammonium nitrate, 

some of which is in solution in the 

water. Two broad classes of water gels 

288 

§ 1910.109 29 CFR Ch. XVII (7–1–13 Edition) 

are (i) those which are sensitized by a 

material classed as an explosive, such 

as TNT or smokeless powder, (ii) those 

which contain no ingredient classified 

as an explosive; these are sensitized 

with metals such as aluminum or with 

other fuels. Water gels may be 

premixed at an explosives plant or 

mixed at the site immediately before 

delivery into the borehole. 

(19) DOT specifications. Regulations of 

the Department of Transportation published in 49 CFR chapter I. 

(b) Miscellaneous provisions—(1) General hazard. No person shall store, handle, or transport explosives or blasting 

agents when such storage, handling, 

and transportation of explosives or 

blasting agents constitutes an undue 

hazard to life. 

(2) [Reserved] 

(c) Storage of explosives—(1) General 

provisions. (i) All Class A, Class B, Class 

C explosives, and special industrial explosives, and any newly developed and 

unclassified explosives, shall be kept in 

magazines which meet the requirements of this paragraph. 

(ii) Blasting caps, electric blasting 

caps, detonating primers, and primed 

cartridges shall not be stored in the 

same magazine with other explosives. 

(iii) Ground around magazines shall 

slope away for drainage. The land surrounding magazines shall be kept clear 

of brush, dried grass, leaves, and other 

materials for a distance of at least 25 

feet. 

(iv) Magazines as required by this 

paragraph shall be of two classes; 

namely, Class I magazines, and Class II 

magazines. 

(v) Class I magazines shall be required where the quantity of explosives 

stored is more than 50 pounds. Class II 

magazines may be used where the 

quantity of explosives stored is 50 

pounds or less. 

(vi) Class I magazines shall be located away from other magazines in 

conformity with Table H–21. 

TABLE H–21—AMERICAN TABLE OF DISTANCES

FOR STORAGE OF EXPLOSIVES 1 5

[As revised and approved by the Institute of Makers of 

Explosives, June 5, 1964] 

Explosives Distances in feet 

when storage is 

barricaded: Separation of magazines 

Pounds over Pounds not over 

2 5 6 

5 10 8 

10 20 10 

20 30 11 

30 40 12 

40 50 14 

50 75 15 

75 100 16 

100 125 18 

125 150 19 

150 200 21 

200 250 23 

250 300 24 

300 400 27 

400 500 29 

500 600 31 

600 700 32 

700 800 33 

800 900 35 

900 1,000 36 

1,000 1,200 39 

1,200 1,400 41 

1,400 1,600 43 

1,600 1,800 44 

1,800 2,000 45 

2,000 2,500 49 

2,500 3,000 52 

3,000 4,000 58 

4,000 5,000 61 

5,000 6,000 65 

6,000 7,000 68 

7,000 8,000 72 

8,000 9,000 75 

9,000 10,000 78 

10,000 12,000 82 

12,000 14,000 87 

14,000 16,000 90 

16,000 18,000 94 

18,000 20,000 98 

20,000 25,000 105 

25,000 30,000 112 

30,000 35,000 119 

35,000 40,000 124 

40,000 45,000 129 

45,000 50,000 135 

50,000 55,000 140 

55,000 60,000 145 

60,000 65,000 150 

65,000 70,000 155 

70,000 75,000 160 

75,000 80,000 165 

80,000 85,000 170 

85,000 90,000 175 

90,000 95,000 180 

95,000 100,000 185 

100,000 110,000 195 

110,000 120,000 205 

120,000 130,000 215 

130,000 140,000 225 

140,000 150,000 235 

150,000 160,000 245 

160,000 170,000 255 

170,000 180,000 265 

180,000 190,000 275 

190,000 200,000 285 

289 

Occupational Safety and Health Admin., Labor § 1910.109 

TABLE H–21—AMERICAN TABLE OF DISTANCES

FOR STORAGE OF EXPLOSIVES 1 5—Continued 

[As revised and approved by the Institute of Makers of 

Explosives, June 5, 1964] 

Explosives Distances in feet 

when storage is 

barricaded: Separation of magazines 

Pounds over Pounds not over 

200,000 210,000 295 

210,000 230,000 315 

230,000 250,000 335 

250,000 275,000 360 

275,000 300,000 385 

1 ‘‘Natural barricade’’ means natural features of the ground, 

such as hills, or timber of sufficient density that the surrounding exposures which require protection cannot be seen 

from the magazine when the trees are bare of leaves. 2 ‘‘Artificial barricade’’ means an artificial mound or revetted wall of earth of a minimum thickness of three feet. 3 ‘‘Barricaded’’ means that a building containing explosives 

is effectually screened from a magazine, building, railway, or 

highway, either by a natural barricade, or by an artificial barricade of such height that a straight line from the top of any 

sidewall of the building containing explosives to the eave line 

of any magazine, or building, or to a point 12 feet above the 

center of a railway or highway, will pass through such intervening natural or artificial barricade. 4When two or more storage magazines are located on the 

same property, each magazine must comply with the minimum distances specified from inhabited buildings, railways, 

and highways, and in addition, they should be separated from 

each other by not less than the distances shown for ‘‘Separation of Magazines,’’ except that the quantity of explosives contained in cap magazines shall govern in regard to the spacing 

of said cap magazines from magazines containing other explosives. If any two or more magazines are separated from 

each other by less than the specified ‘‘Separation of Magazines’’ distances, then such two or more magazines, as a 

group, must be considered as one magazine, and the total 

quantity of explosives stored in such group must be treated as 

if stored in a single magazine located on the site of any magazine of the group, and must comply with the minimum of distances specified from other magazines, inhabited buildings, 

railways, and highways. 5This table applies only to the permanent storage of commercial explosives. It is not applicable to transportation of explosives, or any handling or temporary storage necessary or 

incident thereto. It is not intended to apply to bombs, projectiles, or other heavily encased explosives. 

(vii) Except as provided in subdivision (viii) of this subparagraph, class II 

magazines shall be located in conformity with Table H–21, but may be 

permitted in warehouses and in wholesale and retail establishments when located on a floor which has an entrance 

at outside grade level and the magazine 

is located not more than 10 feet from 

such an entrance. Two class II magazines may be located in the same building when one is used only for blasting 

caps in quantities not in excess of 5,000 

caps and a distance of 10 feet is maintained between magazines. 

(viii) When used for temporary storage at a site for blasting operations, 

class II magazines shall be located 

away from other magazines. A distance 

of at least one hundred and fifty (150) 

feet shall be maintained between class 

II magazines and the work in progress 

when the quantity of explosives kept 

therein is in excess of 25 pounds, and at 

least 50 feet when the quantity of explosives is 25 pounds, or less. 

(ix) This paragraph (c) does not apply 

to: 

(a) Stocks of small arms ammunition, propellant-actuated power cartridges, small arms ammunition primers in quantities of less than 750,000, or 

of smokeless propellants in quantities 

less than 750 pounds; 

(b) Explosive-actuated power devices 

when in quantities less than 50 pounds 

net weight of explosives; 

(c) Fuse lighters and fuse igniters; 

(d) Safety fuses other than cordeau 

detonant fuses. 

(2) Construction of magazines—general. 

(i) Magazines shall be constructed in 

conformity with the provisions of this 

paragraph. 

(ii) Magazines for the storage of explosives, other than black powder, 

Class B and Class C explosives shall be 

bullet resistant, weather resistant, fire 

resistant, and ventilated sufficiently to 

protect the explosive in the specific locality. Magazines used only for storage 

of black powder, Class B and Class C 

explosives shall be weather resistant, 

fire-resistant, and have ventilation. 

Magazines for storage of blasting and 

electric blasting caps shall be weather 

resistant, fire-resistant, and ventilated. 

(iii) Property upon which Class I 

magazines are located and property 

where Class II magazines are located 

outside of buildings shall be posted 

with signs reading ‘‘Explosives—Keep 

Off.’’ 

(iv) Magazines requiring heat shall be 

heated by either hot-water radiant 

heating with the magazine building; or 

air directed into the magazine building 

over either hot water or low pressure 

steam (15 p.s.i.g.) coils located outside 

the magazine building. 

(v) The magazine heating systems 

shall meet the following requirements: 

(a) The radiant heating coils within 

the building shall be installed in such a 

manner that the explosives or explosives containers cannot contact the 

290 

§ 1910.109 29 CFR Ch. XVII (7–1–13 Edition) 

coils and air is free to circulate between the coils and the explosives or 

explosives containers. 

(b) The heating ducts shall be installed in such a manner that the hotair discharge from the duct is not directed against the explosives or explosives containers. 

(c) The heating device used in connection with a magazine shall have 

controls which prevent the ambient 

building temperature from exceeding 

130 °F. 

(d) The electric fan or pump used in 

the heating system for a magazine 

shall be mounted outside and separate 

from the wall of the magazine and shall 

be grounded. 

(e) The electric fan motor and the 

controls for electrical heating devices 

used in heating water or steam shall 

have overloads and disconnects, which 

comply with subpart S of this part. All 

electrical switch gear shall be located 

a minimum distance of 25 feet from the 

magazine. 

(f) The heating source for water or 

steam shall be separated from the magazine by a distance of not less than 25 

feet when electrical and 50 feet when 

fuel fired. The area between the heating unit and the magazine shall be 

cleared of all combustible materials. 

(g) The storage of explosives and explosives containers in the magazine 

shall allow uniform air circulation so 

product temperature uniformity can be 

maintained. 

(vi) When lights are necessary inside 

the magazine, electric safety flashlight, or electric safety lanterns shall 

be used. 

(3) Construction of Class I magazines. 

(i) Class I magazines shall be of masonry construction or of wood or of 

metal construction, or a combination 

of these types. Thickness of masonry 

units shall not be less than 8 inches. 

Hollow masonry units used in construction required to be bullet resistant shall have all hollow spaces filled 

with weak cement or well-tamped sand. 

Wood constructed walls, required to be 

bullet resistant, shall have at least a 6- 

inch space between interior and exterior sheathing and the space between 

sheathing shall be filled with welltamped sand. Metal wall construction, 

when required to be bullet resistant, 

shall be lined with brick at least 4 

inches in thickness or shall have at 

least a 6-inch sandfill between interior 

and exterior walls. 

(ii) Floors and roofs of masonry magazines may be of wood construction. 

Wood floors shall be tongue and 

grooved lumber having a nominal 

thickness of 1 inch. 

(iii) Roofs required to be bullet resistant shall be protected by a sand 

tray located at the line of eaves and 

covering the entire area except that 

necessary for ventilation. Sand in the 

sand tray shall be maintained at a 

depth of not less than 4 inches. 

(iv) All wood at the exterior of magazines, including eaves, shall be protected by being covered with black or 

galvanized steel or aluminum metal of 

thickness of not less than No. 26 gage. 

All nails exposed to the interior of 

magazines shall be well countersunk. 

(v) Foundations for magazines shall 

be of substantial construction and arranged to provide good cross ventilation. 

(vi) Magazines shall be ventilated 

sufficiently to prevent dampness and 

heating of stored explosives. Ventilating openings shall be screened to 

prevent the entrance of sparks. 

(vii) Openings to magazines shall be 

restricted to that necessary for the 

placement and removal of stocks of explosives. Doors for openings in magazines for Class A explosives shall be 

bullet resistant. Doors for magazines 

not required to be bullet resistant shall 

be designed to prevent unauthorized 

entrance to the magazine. 

(viii) [Reserved] 

(ix) Provisions shall be made to prevent the piling of stocks of explosives 

directly against masonry walls, bricklined or sand-filled metal walls and single-thickness metal walls; such protection, however, shall not interfere with 

proper ventilation at the interior of 

side and end walls. 

(4) Construction of Class II magazines. 

(i) Class II magazines shall be of wood 

or metal construction, or a combination thereof. 

(ii) Wood magazines of this class 

shall have sides, bottom, and cover 

constructed of 2-inch hardwood boards 

well braced at corners and protected by 

being entirely covered with sheet 

291 

Occupational Safety and Health Admin., Labor § 1910.109 

metal of not less than No. 20 gage. All 

nails exposed to the interior of the 

magazine shall be well countersunk. 

All metal magazines of this class shall 

have sides, bottom, and cover constructed of sheet metal, and shall be 

lined with three-eighths-inch plywood 

or equivalent. Edges of metal covers 

shall overlap sides at least 1 inch. 

(iii) Covers for both wood- and metalconstructed magazines of this class 

shall be provided with substantial 

strap hinges and shall be provided with 

substantial means for locking. 

(iv) Magazines of this class shall be 

painted red and shall bear lettering in 

white, on all sides and top, at least 3 

inches high, ‘‘Explosives—Keep Fire 

Away.’’ Class II magazines when located in warehouses, and in wholesale 

and retail establishments shall be provided with substantial wheels or casters to facilitate easy removal in the 

case of fire. Where necessary due to climatic conditions, Class II magazines 

shall be ventilated. 

(5) Storage within magazines. (i) Packages of explosives shall be laid flat 

with top side up. Black powder when 

stored in magazines with other explosives shall be stored separately. Black 

powder stored in kegs shall be stored 

on ends, bungs down, or on side, seams 

down. Corresponding grades and brands 

shall be stored together in such a manner that brands and grade marks show. 

All stocks shall be stored so as to be 

easily counted and checked. Packages 

of explosives shall be piled in a stable 

manner. When any kind of explosive is 

removed from a magazine for use, the 

oldest explosive of that particular kind 

shall always be taken first. 

(ii) Packages of explosives shall not 

be unpacked or repacked in a magazine 

nor within 50 feet of a magazine or in 

close proximity to other explosives. 

Tools used for opening packages of explosives shall be constructed of nonsparking materials, except that metal 

slitters may be used for opening fiberboard boxes. A wood wedge and a fiber, 

rubber, or wood mallet shall be used for 

opening or closing wood packages of 

explosives. Opened packages of explosives shall be securely closed before 

being returned to a magazine. 

(iii) Magazines shall not be used for 

the storage of any metal tools nor any 

commodity except explosives, but this 

restriction shall not apply to the storage of blasting agents and blasting supplies. 

(iv) Magazine floors shall be regularly swept, kept clean, dry, free of 

grit, paper, empty used packages, and 

rubbish. Brooms and other cleaning 

utensils shall not have any spark-producing metal parts. Sweepings from 

floors of magazines shall be properly 

disposed of. Magazine floors stained 

with nitroglycerin shall be cleaned according to instructions by the manufacturer. 

(v) When any explosive has deteriorated to an extent that it is in an unstable or dangerous condition, or if nitroglycerin leaks from any explosives, 

then the person in possession of such 

explosive shall immediately proceed to 

destroy such explosive in accordance 

with the instructions of the manufacturer. Only experienced persons shall 

be allowed to do the work of destroying 

explosives. 

(vi) When magazines need inside repairs, all explosives shall be removed 

therefrom and the floors cleaned. In 

making outside repairs, if there is a 

possibility of causing sparks or fire the 

explosives shall be removed from the 

magazine. Explosives removed from a 

magazine under repair shall either be 

placed in another magazine or placed a 

safe distance from the magazine where 

they shall be properly guarded and protected until repairs have been completed, when they shall be returned to 

the magazine. 

(vii) Smoking, matches, open flames, 

spark-producing devices, and firearms 

(except firearms carried by guards) 

shall not be permitted inside of or 

within 50 feet of magazines. The land 

surrounding a magazine shall be kept 

clear of all combustible materials for a 

distance of at least 25 feet. Combustible materials shall not be stored 

within 50 feet of magazines. 

(viii) Magazines shall be in the 

charge of a competent person at all 

times and who shall be held responsible 

for the enforcement of all safety precautions. 

292 

§ 1910.109 29 CFR Ch. XVII (7–1–13 Edition) 

(ix) Explosives recovered from blasting misfires shall be placed in a separate magazine until competent personnel has determined from the manufacturer the method of disposal. Caps 

recovered from blasting misfires shall 

not be reused. Such explosives and caps 

shall then be disposed of in the manner 

recommended by the manufacturer. 

(d) Transportation of explosives—(1) 

General provisions. (i) No employee 

shall be allowed to smoke, carry 

matches or any other flame-producing 

device, or carry any firearms or loaded 

cartridges while in or near a motor vehicle transporting explosives; or drive, 

load, or unload such vehicle in a careless or reckless manner. 

(ii) [Reserved] 

(iii) Explosives shall not be transferred from one vehicle to another 

within the confines of any jurisdiction 

(city, county, State, or other area) 

without informing the fire and police 

departments thereof. In the event of 

breakdown or collision the local fire 

and police departments shall be 

promptly notified to help safeguard 

such emergencies. Explosives shall be 

transferred from the disabled vehicle 

to another only, when proper and 

qualified supervision is provided. 

(iv) Blasting caps or electric blasting 

caps shall not be transported over the 

highways on the same vehicles with 

other explosives, unless packaged, segregated, and transported in accordance 

with the Department of Transportation’s Hazardous Materials Regulations (49 CFR parts 177–180). 

(2) Transportation vehicles. (i) Vehicles 

used for transporting explosives shall 

be strong enough to carry the load 

without difficulty and be in good mechanical condition. If vehicles do not 

have a closed body, the body shall be 

covered with a flameproof and moistureproof tarpaulin or other effective 

protection against moisture and 

sparks. All vehicles used for the transportation of explosives shall have tight 

floors and any exposed spark-producing 

metal on the inside of the body shall be 

covered with wood or other nonsparking materials to prevent contact 

with packages of explosives. Packages 

of explosives shall not be loaded above 

the sides of an open-body vehicle. 

(ii) Every vehicle used for transporting explosives and oxidizing materials listed in paragraph (d)(2)(ii)(a) of 

this section shall be marked as follows: 

(a) Exterior markings or placards required on applicable vehicles shall be 

as follows for the various classes of 

commodities: 

Commodity Type of marking or 

placard 

Explosives, Class A, any quantity 

or a combination of Class A 

and Class B explosives.

Explosives A (Red letters 

on white background). 

Explosives, Class B, and quantity Explosives B (Red letters 

on white background). 

Oxidizing material (blasting 

agents, ammonium nitrate, 

etc.), 1,000 pounds or more 

gross weight.

Oxidizers (Yellow letters 

on black background). 

(b) [Reserved] 

(c) Such markings or placards shall 

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 or other dangerous articles of such type and in such 

quantity as specified in paragraph 

(d)(1)(ii)(a) of this subdivision. The 

front marking or placard may be displayed on the front of either the truck, 

truck body, truck tractor or the trailer. 

(d) Any motor vehicle, trailer, or 

other cargo-carrying body containing 

more than one kind of explosive as well 

as an oxidizing material requiring a 

placard under the provisions of paragraph (d)(2)(ii)(a), the aggregate gross 

weight of which totals 1,000 pounds or 

more, shall be marked or placarded 

‘‘Dangerous’’ as well as ‘‘Explosive A’’ 

or ‘‘Explosive B’’ as appropriate. If explosives Class A and explosives Class B 

are loaded on the same vehicle, the 

‘‘Explosives B’’ marking need not be 

displayed. 

(e) In any combination of two or 

more vehicles containing explosives or 

other dangerous articles each vehicle 

shall be marked or placarded as to its 

contents and in accordance with paragraphs (d)(2)(ii) (a) and (c) of this subdivision. 

(iii) Each motor vehicle used for 

transporting explosives shall be 

equipped with a minimum of two extinguishers, each having a rating of at 

least 10–BC. 

293 

Occupational Safety and Health Admin., Labor § 1910.109 

(a) Only extinguishers listed or approved by a nationally recognized testing laboratory shall be deemed suitable 

for use on explosives-carrying vehicles. 

Refer to §1910.155(c)(3)(iv)(A) for definition of listed, and §1910.7 for nationally 

recognized testing laboratory. 

(b) Extinguishers shall be filled and 

ready for immediate use and located 

near the driver’s seat. Extinguishers 

shall be examined periodically by a 

competent person. 

(iv) A motor vehicle used for transporting explosives shall be given the 

following inspection to determine that 

it is in proper condition for safe transportation of explosives: 

(a) Fire extinguishers shall be filled 

and in working order. 

(b) All electrical wiring shall be completely protected and securely fastened 

to prevent short-circuiting. 

(c) Chassis, motor, pan, and underside 

of body shall be reasonably clean and 

free of excess oil and grease. 

(d) Fuel tank and feedline shall be secure and have no leaks. 

(e) Brakes, lights, horn, windshield 

wipers, and steering apparatus shall 

function properly. 

(f) Tires shall be checked for proper 

inflation and defects. 

(g) The vehicle shall be in proper condition in every other respect and acceptable for handling explosives. 

(3) Operation of transportation vehicles. 

(i) Vehicles transporting explosives 

shall only be driven by and be in the 

charge of a driver who is familiar with 

the traffic regulations, State laws, and 

the provisions of this section. 

(ii) Except under emergency conditions, no vehicle transporting explosives shall be parked before reaching 

its destination, even though attended, 

on any public street adjacent to or in 

proximity to any place where people 

work. 

(iii) Every motor vehicle transporting any quantity of Class A or 

Class B explosives shall, at all times, 

be attended by a driver or other attendant of the motor carrier. This attendant shall have been made aware of 

the class of the explosive material in 

the vehicle and of its inherent dangers, 

and shall have been instructed in the 

measures and procedures to be followed 

in order to protect the public from 

those dangers. He shall have been made 

familiar with the vehicle he is assigned, and shall be trained, supplied 

with the necessary means, and authorized to move the vehicle when required. 

(a) For the purpose of this subdivision, a motor vehicle shall be deemed 

‘‘attended’’ only when the driver or 

other attendant is physically on or in 

the vehicle, or has the vehicle within 

his field of vision and can reach it 

quickly and without any kind of interference ‘‘attended’’ also means that the 

driver or attendant is awake, alert, and 

not engaged in other duties or activities which may divert his attention 

from the vehicle, except for necessary 

communication with public officers, or 

representatives of the carrier shipper, 

or consignee, or except for necessary 

absence from the vehicle to obtain food 

or to provide for his physical comfort. 

(b) However, an explosive-laden vehicle may be left unattended if parked 

within a securely fenced or walled area 

with all gates or entrances locked 

where parking of such vehicle is otherwise permissible, or at a magazine site 

established solely for the purpose of 

storing explosives. 

(iv) No spark-producing metal, sparkproducing metal tools, oils, matches, 

firearms, electric storage batteries, 

flammable substances, acids, oxidizing 

materials, or corrosive compounds 

shall be carried in the body of any 

motor truck and/or vehicle transporting explosives, unless the loading 

of such dangerous articles and the explosives comply with U.S. Department 

of Transportation regulations. 

(v) Vehicles transporting explosives 

shall avoid congested areas and heavy 

traffic. Where routes through congested areas have been designated by 

local authorities such routes shall be 

followed. 

(vi) Delivery shall only be made to 

authorized persons and into authorized 

magazines or authorized temporary 

storage or handling areas. 

(e) Use of explosives and blasting 

agents—(1) General provisions. (i) While 

explosives are being handled or used, 

smoking shall not be permitted and no 

one near the explosives shall possess 

matches, open light or other fire or 

flame. No person shall be allowed to 

294 

§ 1910.109 29 CFR Ch. XVII (7–1–13 Edition) 

handle explosives while under the influence of intoxicating liquors, narcotics, or other dangerous drugs. 

(ii) Original containers or Class II 

magazines shall be used for taking detonators and other explosives from storage magazines to the blasting area. 

(iii) When blasting is done in congested areas or in close proximity to a 

structure, or any other installation 

that may be damaged, the blast shall 

be covered before firing with a mat 

constructed so that it is capable of preventing fragments from being thrown. 

(iv) Persons authorized to prepare explosive charges or conduct blasting operations shall use every reasonable precaution, including but not limited to 

warning signals, flags, barricades, or 

woven wire mats to insure the safety of 

the general public and workmen. 

(v) Blasting operations shall be conducted during daylight hours. 

(vi) Whenever blasting is being conducted in the vicinity of gas, electric, 

water, fire alarm, telephone, telegraph, 

and steam utilities, the blaster shall 

notify the appropriate representatives 

of such utilities at least 24 hours in advance of blasting, specifying the location and intended time of such blasting. Verbal notice shall be confirmed 

with written notice. 

(vii) Due precautions shall be taken 

to prevent accidental discharge of electric blasting caps from current induced 

by radar, radio transmitters, lightning, 

adjacent powerlines, dust storms, or 

other sources of extraneous electricity. 

These precautions shall include: 

(a) The suspension of all blasting operations and removal of persons from 

the blasting area during the approach 

and progress of an electric storm. 

(b) The posting of signs warning 

against the use of mobile radio transmitters on all roads within 350 feet of 

the blasting operations. 

(2) Storage at use sites. (i) Empty containers and paper and fiber packing 

materials which have previously contained explosive materials shall be disposed of in a safe manner, or reused in 

accordance with the Department of 

Transportation’s Hazardous Materials 

Regulations (49 CFR parts 177–180). 

(ii) Containers of explosives shall not 

be opened in any magazine or within 50 

feet of any magazine. In opening kegs 

or wooden cases, no sparking metal 

tools shall be used; wooden wedges and 

either wood, fiber or rubber mallets 

shall be used. Nonsparking metallic 

slitters may be used for opening fiberboard cases. 

(iii) Explosives or blasting equipment 

that are obviously deteriorated or damaged shall not be used. 

(iv) No explosives shall be abandoned. 

(3) Loading of explosives in blast holes. 

(i) All drill holes shall be sufficiently 

large to admit freely the insertion of 

the cartridges of explosives. 

(ii) Tamping shall be done only with 

wood rods without exposed metal parts, 

but nonsparking metal connectors may 

be used for jointed poles. Violent tamping shall be avoided. Primed cartridges 

shall not be tamped. 

(iii) When loading blasting agents 

pneumatically over electric blasting 

caps, semiconductive delivery hose 

shall be used and the equipment shall 

be bonded and grounded. 

(iv) No holes shall be loaded except 

those to be fired in the next round of 

blasting. After loading, all remaining 

explosives shall be immediately returned to an authorized magazine. 

(v) Drilling shall not be started until 

all remaining butts of old holes are examined with a wooden stick for 

unexploded charges, and if any are 

found, they shall be refired before work 

proceeds. 

(vi) No person shall be allowed to 

deepen drill holes which have contained explosives. 

(vii) After loading for a blast is completed, all excess blasting caps or electric blasting caps and other explosives 

shall immediately be returned to their 

separate storage magazines. 

(4) Initiation of explosive charges. 

(i) [Reserved] 

(ii) When fuse is used, the blasting 

cap shall be securely attached to the 

safety fuse with a standard-ring type 

cap crimper. All primers shall be assembled at least 50 feet from any magazine. 

(iii) Primers shall be made up only as 

required for each round of blasting. 

(iv) No blasting cap shall be inserted 

in the explosives without first making 

a hole in the cartridge for the cap with 

a wooden punch of proper size or standard cap crimper. 

295 

Occupational Safety and Health Admin., Labor § 1910.109 

(v) Explosives shall not be extracted 

from a hole that has once been charged 

or has misfired unless it is impossible 

to detonate the unexploded charge by 

insertion of a fresh additional primer. 

(vi) If there are any misfires while 

using cap and fuse, all persons shall be 

required to remain away from the 

charge for at least 1 hour. If electric 

blasting caps are used and a misfire occurs, this waiting period may be reduced to 30 minutes. Misfires shall be 

handled under the direction of the person in charge of the blasting and all 

wires shall be carefully traced and 

search made for unexploded charges. 

(vii) Blasters, when testing circuits 

to charged holes, shall use only blasting galvanometers designed for this 

purpose. 

(viii) Only the employee making 

leading wire connections in electrical 

firing shall be allowed to fire the shot. 

Leading wires shall remain shorted and 

not be connected to the blasting machine or other source of current until 

the charge is to be fired. 

(5) Warning required. Before a blast is 

fired, the employer shall require that a 

loud warning signal be given by the 

person in charge, who has made certain 

that all surplus explosives are in a safe 

place, all persons and vehicles are at a 

safe distance or under sufficient cover, 

and that an adequate warning has been 

given. 

(f) Explosives at piers, railway stations, 

and cars or vessels not otherwise specified 

in this standard—(1) Railway cars. Except in an emergency and with permission of the local authority, no person 

shall have or keep explosives in a railway car unless said car and contents 

and methods of loading are in accordance with the U.S. Department of 

Transportation Regulations for the 

Transportation of Explosives, 49 CFR 

chapter I. 

(2) Packing and marking. No person 

shall deliver any explosive to any carrier unless such explosive conforms in 

all respects, including marking and 

packing, to the U.S. Department of 

Transportation Regulations for the 

Transportation of Explosives. 

(3) Marking cars. Every railway car 

containing explosives which has 

reached its designation, or is stopped 

in transit so as no longer to be in interstate commerce, shall have attached to 

both sides and ends of the car, cards 

with the words ‘‘Explosives—Handle 

Carefully—Keep Fire Away’’ in red letters at least 11⁄2 inches high on a white 

background. 

(4) Storage. Any explosives at a railway facility, truck terminal, pier, 

wharf harbor facility, or airport terminal whether for delivery to a consignee, or forwarded to some other destination shall be kept in a safe place, 

isolated as far as practicable and in 

such manner that they can be easily 

and quickly removed. 

(5) Hours of transfer. Explosives shall 

not be delivered to or received from 

any railway station, truck terminal, 

pier, wharf, harbor facility, or airport 

terminal between the hours of sunset 

and sunrise. 

(g) Blasting agents—(1) General. Unless 

otherwise set forth in this paragraph, 

blasting agents, excluding water gels, 

shall be transported, stored, and used 

in the same manner as explosives. 

Water gels are covered in paragraph (h) 

of this section. 

(2) Fixed location mixing. (i) [Reserved] 

(ii) Buildings used for the mixing of 

blasting agents shall conform to the requirements of this section. 

(a) Buildings shall be of noncombustible construction or sheet metal on 

wood studs. 

(b) Floors in a mixing plant shall be 

of concrete or of other nonabsorbent 

materials. 

(c) All fuel oil storage facilities shall 

be separated from the mixing plant and 

located in such a manner that in case 

of tank rupture, the oil will drain away 

from the mixing plant building. 

(d) The building shall be well ventilated. 

(e) Heating units which do not depend 

on combustion processes, when properly designed and located, may be used 

in the building. All direct sources of 

heat shall be provided exclusively from 

units located outside the mixing building. 

(f) All internal-combustion engines 

used for electric power generation shall 

be located outside the mixing plant 

building, or shall be properly ventilated and isolated by a firewall. The exhaust systems on all such engines shall 

296 

§ 1910.109 29 CFR Ch. XVII (7–1–13 Edition) 

be located so any spark emission cannot be a hazard to any materials in or 

adjacent to the plant. 

(iii) Equipment used for mixing 

blasting agents shall conform to the requirements of this subdivision. 

(a) The design of the mixer shall minimize the possibility of frictional heating, compaction, and especially confinement. All bearings and drive assemblies shall be mounted outside the 

mixer and protected against the accumulation of dust. All surfaces shall be 

accessible for cleaning. 

(b) Mixing and packaging equipment 

shall be constructed of materials compatible with the fuel-ammonium nitrate composition. 

(c) Suitable means shall be provided 

to prevent the flow of fuel oil to the 

mixer in case of fire. In gravity flow 

systems an automatic spring-loaded 

shutoff valve with fusible link shall be 

installed. 

(iv) The provisions of this subdivision 

shall be considered when determining 

blasting agent compositions. 

(a) The sensitivity of the blasting 

agent shall be determined by means of 

a No. 8 test blasting cap at regular intervals and after every change in formulation. 

(b) Oxidizers of small particle size, 

such as crushed ammonium nitrate 

prills or fines, may be more sensitive 

than coarser products and shall, therefore, be handled with greater care. 

(c) No hydrocarbon liquid fuel with 

flashpoint lower than that of No. 2 diesel fuel oil 125 °F. minimum shall be 

used. 

(d) Crude oil and crankcase oil shall 

not be used. 

(e) Metal powders such as aluminum 

shall be kept dry and shall be stored in 

containers or bins which are moistureresistant or weathertight. Solid fuels 

shall be used in such manner as to minimize dust explosion hazards. 

(f) Peroxides and chlorates shall not 

be used. 

(v) All electrical switches, controls, 

motors, and lights located in the mixing room shall conform to the requirements in subpart S of this part for 

Class II, Division 2 locations; otherwise 

they shall be located outside the mixing room. The frame of the mixer and 

all other equipment that may be used 

shall be electrically bonded and be provided with a continuous path to the 

ground. 

(vi) Safety precautions at mixing 

plants shall include the requirements 

of this subdivision. 

(a) Floors shall be constructed so as 

to eliminate floor drains and piping 

into which molten materials could flow 

and be confined in case of fire. 

(b) The floors and equipment of the 

mixing and packaging room shall be 

cleaned regularly and thoroughly to 

prevent accumulation of oxidizers or 

fuels and other sensitizers. 

(c) The entire mixing and packaging 

plant shall be cleaned regularly and 

thoroughly to prevent excessive accumulation of dust. 

(d) Smoking, matches, open flames, 

spark-producing devices, and firearms 

(except firearms carried by guards) 

shall not be permitted inside of or 

within 50 feet of any building or facility used for the mixing of blasting 

agents. 

(e) The land surrounding the mixing 

plant shall be kept clear of brush, dried 

grass, leaves, and other materials for a 

distance of at least 25 feet. 

(f) Empty ammonium nitrate bags 

shall be disposed of daily in a safe manner. 

(g) No welding shall be permitted or 

open flames used in or around the mixing or storage area of the plant unless 

the equipment or area has been completely washed down and all oxidizer 

material removed. 

(h) Before welding or repairs to hollow shafts, all oxidizer material shall 

be removed from the outside and inside 

of the shaft and the shaft vented with 

a minimum one-half inch diameter 

opening. 

(i) Explosives shall not be permitted 

inside of or within 50 feet of any building or facility used for the mixing of 

blasting agents. 

(3) Bulk delivery and mixing vehicles. 

(i) The provisions of this paragraph 

shall apply to off-highway private operations as well as to all public highway 

movements. 

(ii) A bulk vehicle body for delivering 

and mixing blasting agents shall conform with the requirements of this 

paragraph (ii). 

297 

Occupational Safety and Health Admin., Labor § 1910.109 

(a) The body shall be constructed of 

noncombustible materials. 

(b) Vehicles used to transport bulk 

premixed blasting agents on public 

highways shall have closed bodies. 

(c) All moving parts of the mixing 

system shall be designed as to prevent 

a heat buildup. Shafts or axles which 

contact the product shall have outboard bearings with 1-inch minimum 

clearance between the bearings and the 

outside of the product container. Particular attention shall be given to the 

clearances on all moving parts. 

(d) A bulk delivery vehicle shall be 

strong enough to carry the load without difficulty and be in good mechanical condition. 

(iii) Operation of bulk delivery vehicles shall conform to the requirements 

of this subdivision. These include the 

placarding requirements as specified by 

Department of Transportation. 

(a) The operator shall be trained in 

the safe operation of the vehicle together with its mixing, conveying, and 

related equipment. The employer shall 

assure that the operator is familiar 

with the commodities being delivered 

and the general procedure for handling 

emergency situations. 

(b) The hauling of either blasting 

caps or other explosives but not both, 

shall be permitted on bulk trucks provided that a special wood or nonferrous-lined container is installed for 

the explosives. Such blasting caps or 

other explosives shall be in DOT-specified shipping containers: see 49 CFR 

chapter I. 

(c) No person shall smoke, carry 

matches or any flame-producing device, or carry any firearms while in or 

about bulk vehicles effecting the mixing transfer or down-the-hole loading 

of blasting agents at or near the blasting site. 

(d) Caution shall be exercised in the 

movement of the vehicle in the blasting area to avoid driving the vehicle 

over or dragging hoses over firing lines, 

cap wires, or explosive materials. The 

employer shall assure that the driver, 

in moving the vehicle, has assistance of 

a second person to guide his movements. 

(e) No intransit mixing of materials 

shall be performed. 

(iv) Pneumatic loading from bulk delivery vehicles into blastholes primed 

with electric blasting caps or other 

static-sensitive systems shall conform 

to the requirements of this subdivision. 

(a) A positive grounding device shall 

be used to prevent the accumulation of 

static electricity. 

(b) A discharge hose shall be used 

that has a resistance range that will 

prevent conducting stray currents, but 

that is conductive enough to bleed off 

static buildup. 

(c) A qualified person shall evaluate 

all systems to determine if they will 

adequately dissipate static under potential field conditions. 

(v) Repairs to bulk delivery vehicles 

shall conform to the requirements of 

this section. 

(a) No welding or open flames shall 

be used on or around any part of the 

delivery equipment unless it has been 

completely washed down and all oxidizer material removed. 

(b) Before welding or making repairs 

to hollow shafts, the shaft shall be 

thoroughly cleaned inside and out and 

vented with a minimum one-half-inch 

diameter opening. 

(4) Bulk storage bins. (i) The bin, including supports, shall be constructed 

of compatible materials, waterproof, 

and adequately supported and braced 

to withstand the combination of all 

loads including impact forces arising 

from product movement within the bin 

and accidental vehicle contact with the 

support legs. 

(ii) The bin discharge gate shall be 

designed to provide a closure tight 

enough to prevent leakage of the 

stored product. Provision shall also be 

made so that the gate can be locked. 

(iii) Bin loading manways or access 

hatches shall be hinged or otherwise 

attached to the bin and be designed to 

permit locking. 

(iv) Any electrically driven conveyors for loading or unloading bins 

shall conform to the requirements of 

subpart S of this part. They shall be 

designed to minimize damage from corrosion. 

(v) Bins containing blasting agent 

shall be located, with respect to inhabited buildings, passenger railroads, and 

public highways, in accordance with 

Table-21 and separation from other 

298 

§ 1910.109 29 CFR Ch. XVII (7–1–13 Edition) 

blasting agent storage and explosives 

storage shall be in conformity with 

Table H–22. 

(vi) Bins containing ammonium nitrate shall be separated from blasting 

agent storage and explosives storage in 

conformity with Table H–22. 

TABLE H–22—TABLE OF RECOMMENDED SEPARATION DISTANCES OF AMMONIUM NITRATE

AND BLASTING AGENTS FROM EXPLOSIVES OR

BLASTING AGENTS 1 6

Donor weight Minimum separation 

distance of receptor 

when barricaded 2 (ft.) 

Minimum 

thickness 

of artificial 

barricades 5

(in.) 

Pounds 

over 

Pounds 

not over Ammonium nitrate 3Blasting 

agent 4

100 3 11 12 

100 300 4 14 12 

300 600 5 18 12 

600 1,000 6 22 12 

1,000 1,600 7 25 12 

1,600 2,000 8 29 12 

2,000 3,000 9 32 15 

3,000 4,000 10 36 15 

4,000 6,000 11 40 15 

6,000 8,000 12 43 20 

8,000 10,000 13 47 20 

10,000 12,000 14 50 20 

12,000 16,000 15 54 25 

16,000 20,000 16 58 25 

20,000 25,000 18 65 25 

25,000 30,000 19 68 30 

30,000 35,000 20 72 30 

35,000 40,000 21 76 30 

40,000 45,000 22 79 35 

45,000 50,000 23 83 35 

50,000 55,000 24 86 35 

55,000 60,000 25 90 35 

60,000 70,000 26 94 40 

70,000 80,000 28 101 40 

80,000 90,000 30 108 40 

90,000 100,000 32 115 40 

100,000 120,000 34 122 50 

120,000 140,000 37 133 50 

140,000 160,000 40 144 50 

160,000 180,000 44 158 50 

180,000 200,000 48 173 50 

200,000 220,000 52 187 60 

220,000 250,000 56 202 60 

250,000 275,000 60 216 60 

275,000 300,000 64 230 60 

1These distances apply to the separation of stores only. 

Table H–21 shall be used in determining separation distances 

from inhabited buildings, passenger railways, and public highways. 2When the ammonium nitrate and/or blasting agent is not 

barricaded, the distances shown in the table shall be multiplied by six. These distances allow for the possibility of high 

velocity metal fragments from mixers, hoppers, truck bodies, 

sheet metal structures, metal container, and the like which 

may enclose the ‘‘donor’’. Where storage is in bullet-resistant 

magazines recommended for explosives or where the storage 

is protected by a bullet-resistant wall, distances, and barricade 

thicknesses in excess of those prescribed in Table H–21 are 

not required. 

3The distances in the table apply to ammonium nitrate that 

passes the insensitivity test prescribed in the definition of ammonium nitrate fertilizer promulgated by the National Plant 

Food Institute*; and ammonium nitrate failing to pass said test 

shall be stored at separation distances determined by competent persons. (*Definition and Test Procedures for Ammonium Nitrate Fertilizer, National Plant Food Institute, November 1964.) 4These distances apply to nitro-carbo-nitrates and blasting 

agents which pass the insensitivity test prescribed in the U.S. 

Department of Transportation (DOT) regulations. 5Earth, or sand dikes, or enclosures filled with the prescribed minimum thickness of earth or sand are acceptable 

artificial barricades. Natural barricades, such as hills or timber 

of sufficient density that the surrounding exposures which require protection cannot be seen from the ‘‘donor’’ when the 

trees are bare of leaves, are also acceptable. 6When the ammonium nitrate must be counted in determining the distances to be maintained from inhabited buildings, passenger railways and public highways, it may be 

counted at one-half its actual weight because its blast effect is 

lower. 

NOTE 7: Guide to use of table of recommended separation 

distances of ammonium nitrate and blasting agents from explosives or blasting agents. 

(a) Sketch location of all potential donor and acceptor materials together with the maximum mass of material to be allowed in that vicinity. (Potential donors are high explosives, 

blasting agents, and combination of masses of detonating materials. Potential acceptors are high explosives, blasting 

agents, and ammonium nitrate.) 

(b) Consider separately each donor mass in combination 

with each acceptor mass. If the masses are closer than table 

allowance (distances measured between nearest edges), the 

combination of masses becomes a new potential donor of 

weight equal to the total mass. When individual masses are 

considered as donors, distances to potential acceptors shall 

be measured between edges. When combined masses within 

propagating distance of each other are considered as a 

donor, the appropriate distance to the edge of potential acceptors shall be computed as a weighted distance from the 

combined masses. 

Calculation of weighted distance from combined masses: 

Let M2, M3 . . . Mn be donor masses to be combined. 

M1 is a potential acceptor mass. 

D12 is distance from M1 to M2 (edge to edge). 

D13 is distance from M1 to M3 (edge to edge), etc. 

To find weighted distance [D1(2,3 . . . n)] from combined 

masses to M1, add the products of the individual masses and 

distances and divide the total by the sum of the masses thus: 

D1(2, 3 . . . n)=M2×D12+M3×D12 . . . +Mn×D12M2+M3 . . . +Mn

Propagation is possible if either an individual donor mass is 

less than the tabulated distance from an acceptor or a combined mass is less than the weighted distance from an acceptor. 

(c) In determining the distances separating highways, railroads, and inhabited buildings from potential explosions (as 

prescribed in Table H–21), the sum of all masses which may 

propagate (i.e., lie at distances less than prescribed in the 

Table) from either individual or combined donor masses are 

included. However, when the ammonium nitrate must be included, only 50 percent of its weight shall be used because of 

its reduced blast effects. In applying Table H–21 to distances 

from highways, railroads, and inhabited buildings, distances 

are measured from the nearest edge of potentially explodable 

material as prescribed in Table H–21, Note 5. 

(d) When all or part of a potential acceptor comprises Explosives Class A as defined in DOT regulations, storage in 

bullet-resistant magazines is required. Safe distances to 

stores in bullet-resistant magazines may be obtained from the 

intermagazine distances prescribed in Table H–21. 

(e) Barricades must not have line-of-sight openings between potential donors and acceptors which permit blast or 

missiles to move directly between masses. 

(f) Good housekeeping practices shall be maintained 

around any bin containing ammonium nitrate or blasting 

agent. This includes keeping weeds and other combustible 

materials cleared within 25 feet of such bin. Accumulation of 

spilled product on the ground shall be prevented. 

(5) Storage of blasting agents and supplies. (i) Blasting agents and oxidizers 

used for mixing of blasting agents shall 

299 

Occupational Safety and Health Admin., Labor § 1910.109 

be stored in the manner set forth in 

this subdivision. 

(a) Blasting agents or ammonium nitrate, when stored in conjunction with 

explosives, shall be stored in the manner set forth in paragraph (c) of this 

section for explosives. The mass of 

blasting agents and one-half the mass 

of ammonium nitrate shall be included 

when computing the total quantity of 

explosives for determining distance requirements. 

(b) Blasting agents, when stored entirely separate from explosives, may be 

stored in the manner set forth in paragraph (c) of this section or in one-story 

warehouses (without basements) which 

shall be: 

(1) Noncombustible or fire resistive; 

(2) Constructed so as to eliminate 

open floor drains and piping into which 

molten materials could flow and be 

confined in case of fire; 

(3) Weather resistant; 

(4) Well ventilated; and 

(5) Equipped with a strong door kept 

securely locked except when open for 

business. 

(c) Semitrailer or full-trailer vans 

used for highway or onsite transportation of the blasting agents are satisfactory for temporarily storing these 

materials, provided they are located in 

accordance with Table H–22 with respect to one another. Trailers shall be 

provided with substantial means for 

locking, and the trailer doors shall be 

kept locked, except during the time of 

placement and removal of stocks of 

blasting agents. 

(ii) Warehouses used for the storage 

of blasting agents separate from explosives shall be located as set forth in 

this subdivision. 

(a) Warehouses used for the storage 

of blasting agents shall be located in 

Table H–22 with respect to one another. 

(b) If both blasting agents and ammonium nitrate are handled or stored 

within the distance limitations prescribed through paragraph (g)(2) of this 

section, one-half the mass of the ammonium nitrate shall be added to the 

mass of the blasting agent when computing the total quantity of explosives 

for determining the proper distance for 

compliance with Table H–21. 

(iii) Smoking, matches, open flames, 

spark producing devices, and firearms 

are prohibited inside of or within 50 

feet of any warehouse used for the storage of blasting agents. Combustible 

materials shall not be stored within 50 

feet of warehouses used for the storage 

of blasting agents. 

(iv) The interior of warehouses used 

for the storage of blasting agents shall 

be kept clean and free from debris and 

empty containers. Spilled materials 

shall be cleaned up promptly and safely 

removed. Combustible materials, flammable liquids, corrosive acids, chlorates, or nitrates shall not be stored in 

any warehouse used for blasting agents 

unless separated therefrom by a fire resistive separation of not less than 1 

hour resistance. The provisions of this 

subdivision shall not prohibit the storage of blasting agents together with 

nonexplosive blasting supplies. 

(v) Piles of ammonium nitrate and 

warehouses containing ammonium nitrate shall be adequately separated 

from readily combustible fuels. 

(vi) Caked oxidizers, either in bags or 

in bulk, shall not be loosened by blasting. 

(vii) Every warehouse used for the 

storage of blasting agents shall be 

under the supervision of a competent 

person. 

(6) Transportation of packaged blasting 

agents. (i) When blasting agents are 

transported in the same vehicle with 

explosives, all of the requirements of 

paragraph (d) of this section shall be 

complied with. 

(ii) Vehicles transporting blasting 

agents shall only be driven by and be in 

charge of a driver in possession of a 

valid motor vehicle operator’s license. 

Such a person shall also be familiar 

with the State’s vehicle and traffic 

laws. 

(iii) No matches, firearms, acids, or 

other corrosive liquids shall be carried 

in the bed or body of any vehicle containing blasting agents. 

(iv) No person shall be permitted to 

ride upon, drive, load, or unload a vehicle containing blasting agents while 

smoking or under the influence of intoxicants, narcotics, or other dangerous drugs. 

(v) [Reserved] 

(vi) Vehicles transporting blasting 

agents shall be in safe operating condition at all times. 

300 

§ 1910.109 29 CFR Ch. XVII (7–1–13 Edition) 

(7) Use of blasting agents. Persons 

using blasting agents shall comply 

with all of the applicable provisions of 

paragraph (e) of this section. 

(h) Water gel (Slurry) explosives and 

blasting agents—(1) General provisions. 

Unless otherwise set forth in this paragraph, water gels shall be transported, 

stored and used in the same manner as 

explosives or blasting agents in accordance with the classification of the 

product. 

(2) Types and classifications. (i) Water 

gels containing a substance in itself 

classified as an explosive shall be classified as an explosive and manufactured, transported, stored, and used as 

specified for ‘‘explosives’’ in this section, except as noted in subdivision (iv) 

of this subparagraph. 

(ii) Water gels containing no substance in itself classified as an explosive and which are cap-sensitive as defined in paragraph (a) of this section 

under Blasting Agent shall be classified 

as an explosive and manufactured, 

transported, stored and used as specified for ‘‘explosives’’ in this section. 

(iii) Water gels containing no substance in itself classified as an explosive and which are not cap-sensitive as 

defined in paragraph (a) of this section 

under Blasting Agent shall be classified 

as blasting agents and manufactured, 

transported, stored, and used as specified for ‘‘blasting agents’’ in this section. 

(iv) When tests on specific formulations of water gels result in Department of Transportation classification 

as a Class B explosive, bullet-resistant 

magazines are not required, see paragraph (c)(2)(ii) of this section. 

(3) Fixed location mixing. 

(i) [Reserved] 

(ii) Buildings used for the mixing of 

water gels shall conform to the requirements of this subdivision. 

(a) Buildings shall be of noncombustible construction or sheet metal on 

wood studs. 

(b) Floors in a mixing plant shall be 

of concrete or of other nonabsorbent 

materials. 

(c) Where fuel oil is used all fuel oil 

storage facilities shall be separated 

from the mixing plant and located in 

such a manner that in case of tank rupture, the oil will drain away from the 

mixing plant building. 

(d) The building shall be well ventilated. 

(e) Heating units that do not depend 

on combustion processes, when properly designed and located, may be used 

in the building. All direct sources of 

heat shall be provided exclusively from 

units located outside of the mixing 

building. 

(f) All internal-combustion engines 

used for electric power generation shall 

be located outside the mixing plant 

building, or shall be properly ventilated and isolated by a firewall. The exhaust systems on all such engines shall 

be located so any spark emission cannot be a hazard to any materials in or 

adjacent to the plant. 

(iii) Ingredients of water gels shall 

conform to the requirements of this 

subdivision. 

(a) Ingredients in themselves classified as Class A or Class B explosives 

shall be stored in conformity with 

paragraph (c) of this section. 

(b) Nitrate-water solutions may be 

stored in tank cars, tank trucks, or 

fixed tanks without quantity or distance limitations. Spills or leaks which 

may contaminate combustible materials shall be cleaned up immediately. 

(c) Metal powders such as aluminum 

shall be kept dry and shall be stored in 

containers or bins which are moistureresistant or weathertight. Solid fuels 

shall be used in such manner as to minimize dust explosion hazards. 

(d) Ingredients shall not be stored 

with incompatible materials. 

(e) Peroxides and chlorates shall not 

be used. 

(iv) Mixing equipment shall comply 

with the requirements of this subdivision. 

(a) The design of the processing 

equipment, including mixing and conveying equipment, shall be compatible 

with the relative sensitivity of the materials being handled. Equipment shall 

be designed to minimize the possibility 

of frictional heating, compaction, overloading, and confinement. 

(b) Both equipment and handling procedures shall be designed to prevent 

the introduction of foreign objects or 

materials. 

301 

Occupational Safety and Health Admin., Labor § 1910.109 

(c) Mixers, pumps, valves, and related 

equipment shall be designed to permit 

regular and periodic flushing, cleaning, 

dismantling, and inspection. 

(d) All electrical equipment including 

wiring, switches, controls, motors, and 

lights, shall conform to the requirements of subpart S of this part. 

(e) All electric motors and generators 

shall be provided with suitable overload protection devices. Electrical generators, motors, proportioning devices, 

and all other electrical enclosures shall 

be electrically bonded. The grounding 

conductor to all such electrical equipment shall be effectively bonded to the 

service-entrance ground connection 

and to all equipment ground connections in a manner so as to provide a 

continuous path to ground. 

(v) Mixing facilities shall comply 

with the fire prevention requirements 

of this subdivision. 

(a) The mixing, loading, and ingredient transfer areas where residues or 

spilled materials may accumulate shall 

be cleaned periodically. A cleaning and 

collection system for dangerous residues shall be provided. , 

(b) A daily visual inspection shall be 

made of mixing, conveying, and electrical equipment to establish that such 

equipment is in good operating condition. A program of systematic maintenance shall be conducted on regular 

schedule. 

(c) Heaters which are not dependent 

on the combustion process within the 

heating unit may be used within the 

confines of processing buildings, or 

compartments, if provided with temperature and safety controls and located away from combustible materials 

and the finished product. 

(4) Bulk delivery and mixing vehicles. 

(i) The design of vehicles shall comply 

with the requirements of this subdivision. 

(a) Vehicles used over public highways for the bulk transportation of 

water gels or of ingredients classified 

as dangerous commodities, shall meet 

the requirements of the Department of 

Transportation and shall meet the requirements of paragraphs (d) and (g)(6) 

of this section. 

(b) When electric power is supplied by 

a self-contained motor generator located on the vehicle the generator 

shall be at a point separate from where 

the water gel is discharged. 

(c) The design of processing equipment and general requirements shall 

conform to subparagraphs (3) (iii) and 

(iv) of this paragraph. 

(d) A positive action parking brake, 

which will set the wheel brakes on at 

least one axle shall be provided on vehicles when equipped with air brakes 

and shall be used during bulk delivery 

operations. Wheel chocks shall supplement parking brakes whenever conditions may require. 

(ii) Operation of bulk delivery and 

mixing vehicles shall comply with the 

requirements of this subdivision. 

(a) The placarding requirements contained in DOT regulations apply to vehicles carrying water gel explosives or 

blasting agents. 

(b) The operator shall be trained in 

the safe operation of the vehicle together with its mixing, conveying, and 

related equipment. He shall be familiar 

with the commodities being delivered 

and the general procedure for handling 

emergency situations. 

(c) The hauling of either blasting 

caps or other explosives, but not both, 

shall be permitted on bulk trucks provided that a special wood or nonferrous-lined container is installed for 

the explosives. Such blasting caps or 

other explosives shall be in DOT-specified shipping containers; see 49 CFR 

chapter I. 

(d) No person shall be allowed to 

smoke, carry matches or any flameproducing device, or carry any firearms 

while in or about bulk vehicles effecting the mixing, transfer, or down-thehole loading of water gels at or near 

the blasting site. 

(e) Caution shall be exercised in the 

movement of the vehicle in the blasting area to avoid driving the vehicle 

over or dragging hoses over firing lines, 

cap wires, or explosive materials. The 

employer shall furnish the driver the 

assistance of a second person to guide 

the driver’s movements. 

(f) No intransit mixing of materials 

shall be performed. 

(g) The location chosen for water gel 

or ingredient transfer from a support 

vehicle into the borehole loading vehicle shall be away from the blasthole 

302 

§ 1910.109 29 CFR Ch. XVII (7–1–13 Edition) 

site when the boreholes are loaded or 

in the process of being loaded. 

(i) Storage of ammonium nitrate—(1) 

Scope and definitions. (i)(a) Except as 

provided in paragraph (i)(1)(i)(d) of this 

paragraph applies to the storage of ammonium nitrate in the form of crystals, 

flakes, grains, or prills including fertilizer grade, dynamite grade, nitrous 

oxide grade, technical grade, and other 

mixtures containing 60 percent or more 

ammonium nitrate by weight but does 

not apply to blasting agents. 

(b) This paragraph does not apply to 

the transportation of ammonium nitrate. 

(c) This paragraph does not apply to 

storage under the jurisdiction of and in 

compliance with the regulations of the 

U.S. Coast Guard (see 46 CFR parts 146– 

149). 

(d) The storage of ammonium nitrate 

and ammonium nitrate mixtures that 

are more sensitive than allowed by the 

‘‘Definition of Test Procedures for Ammonium Nitrate Fertilizer’’ is prohibited. 

(ii)(a) [Reserved] 

(b) The standards for ammonium nitrate (nitrous oxide grade) are those 

found in the ‘‘Specifications, Properties, and Recommendations for Packaging, Transportation, Storage, and 

Use of Ammonium Nitrate’’, available 

from the Compressed Gas Association, 

Inc., which is incorporated by reference 

as specified in §1910.6. 

(2) General provisions. (i) This paragraph applies to all persons storing, 

having, or keeping ammonium nitrate, 

and to the owner or lessee of any building, premises, or structure in which 

ammonium nitrate is stored in quantities of 1,000 pounds or more. 

(ii) Approval of large quantity storage shall be subject to due consideration of the fire and explosion hazards, 

including exposure to toxic vapors 

from burning or decomposing ammonium nitrate. 

(iii)(a) Storage buildings shall not 

have basements unless the basements 

are open on at least one side. Storage 

buildings shall not be over one story in 

height. 

(b) Storage buildings shall have adequate ventilation or be of a construction that will be self-ventilating in the 

event of fire. 

(c) The wall on the exposed side of a 

storage building within 50 feet of a 

combustible building, forest, piles of 

combustible materials and similar exposure hazards shall be of fire-resistive 

construction. In lieu of the fire-resistive wall, other suitable means of exposure protection such as a free standing 

wall may be used. The roof coverings 

shall be Class C or better, as defined in 

the Manual on Roof Coverings, NFPA 

203M–1970, which is incorporated by reference as specified in §1910.6. 

(d) All flooring in storage and handling areas, shall be of noncombustible 

material or protected against impregnation by ammonium nitrate and shall 

be without open drains, traps, tunnels, 

pits, or pockets into which any molten 

ammonium nitrate could flow and be 

confined in the event of fire. 

(e) The continued use of an existing 

storage building or structure not in 

strict conformity with this paragraph 

may be approved in cases where such 

continued use will not constitute a 

hazard to life. 

(f) Buildings and structures shall be 

dry and free from water seepage 

through the roof, walls, and floors. 

(3) Storage of ammonium nitrate in 

bags, drums, or other containers. (i)(a) 

Bags and containers used for ammonium nitrate must comply with specifications and standards required for use 

in interstate commerce (see 49 CFR 

chapter I). 

(b) Containers used on the premises 

in the actual manufacturing or processing need not comply with provisions 

of paragraph (i)(3)(i)(a) of this paragraph. 

(ii)(a) Containers of ammonium nitrate shall not be accepted for storage 

when the temperature of the ammonium nitrate exceeds 130 °F. 

(b) Bags of ammonium nitrate shall 

not be stored within 30 inches of the 

storage building walls and partitions. 

(c) The height of piles shall not exceed 20 feet. The width of piles shall 

not exceed 20 feet and the length 50 feet 

except that where the building is of 

noncombustible construction or is protected by automatic sprinklers the 

length of piles shall not be limited. In 

no case shall the ammonium nitrate be 

stacked closer than 36 inches below the 

303 

Occupational Safety and Health Admin., Labor § 1910.109 

roof or supporting and spreader beams 

overhead. 

(d) Aisles shall be provided to separate piles by a clear space of not less 

than 3 feet in width. At least one service or main aisle in the storage area 

shall be not less than 4 feet in width. 

(4) Storage of bulk ammonium nitrate. 

(i)(a) Warehouses shall have adequate 

ventilation or be capable of adequate 

ventilation in case of fire. 

(b) Unless constructed of noncombustible material or unless adequate facilities for fighting a roof fire are 

available, bulk storage structures shall 

not exceed a height of 40 feet. 

(ii)(a) Bins shall be clean and free of 

materials which may contaminate ammonium nitrate. 

(b) Due to the corrosive and reactive 

properties of ammonium nitrate, and 

to avoid contamination, galvanized 

iron, copper, lead, and zinc shall not be 

used in a bin construction unless suitably protected. Aluminum bins and 

wooden bins protected against impregnation by ammonium nitrate are permissible. The partitions dividing the 

ammonium nitrate storage from other 

products which would contaminate the 

ammonium nitrate shall be of tight 

construction. 

(c) The ammonium nitrate storage 

bins or piles shall be clearly identified 

by signs reading ‘‘Ammonium Nitrate’’ 

with letters at least 2 inches high. 

(iii)(a) Piles or bins shall be so sized 

and arranged that all material in the 

pile is moved out periodically in order 

to minimize possible caking of the 

stored ammonium nitrate. 

(b) Height or depth of piles shall be 

limited by the pressure-setting tendency of the product. However, in no 

case shall the ammonium nitrate be 

piled higher at any point than 36 inches 

below the roof or supporting and 

spreader beams overhead. 

(c) Ammonium nitrate shall not be 

accepted for storage when the temperature of the product exceeds 130 °F. 

(d) Dynamite, other explosives, and 

blasting agents shall not be used to 

break up or loosen caked ammonium 

nitrate. 

(5) Contaminants. (i)(a) Ammonium 

nitrate shall be in a separate building 

or shall be separated by approved type 

firewalls of not less than 1 hour fire-resistance rating from storage of organic 

chemicals, acids, or other corrosive 

materials, materials that may require 

blasting during processing or handling, 

compressed flammable gases, flammable and combustible materials or 

other contaminating substances, including but not limited to animal fats, 

baled cotton, baled rags, baled scrap 

paper, bleaching powder, burlap or cotton bags, caustic soda, coal, coke, charcoal, cork, camphor, excelsior, fibers of 

any kind, fish oils, fish meal, foam rubber, hay, lubricating oil, linseed oil, or 

other oxidizable or drying oils, naphthalene, oakum, oiled clothing, oiled 

paper, oiled textiles, paint, straw, sawdust, wood shavings, or vegetable oils. 

Walls referred to in this subdivision 

need extend only to the underside of 

the roof. 

(b) In lieu of separation walls, ammonium nitrate may be separated from 

the materials referred to in paragraph 

(a) of this section by a space of at least 

30 feet. 

(c) Flammable liquids such as gasoline, kerosene, solvents, and light fuel 

oils shall not be stored on the premises 

except when such storage conforms to 

§1910.106, and when walls and sills or 

curbs are provided in accordance with 

paragraphs (i)(5)(i) (a) or (b) of this section. 

(d) LP-Gas shall not be stored on the 

premises except when such storage conforms to §1910.110. 

(ii)(a) Sulfur and finely divided metals shall not be stored in the same 

building with ammonium nitrate except when such storage conforms to 

paragraphs (a) through (h) of this section. 

(b) Explosives and blasting agents 

shall not be stored in the same building 

with ammonium nitrate except on the 

premises of makers, distributors, and 

user-compounders of explosives or 

blasting agents. 

(c) Where explosives or blasting 

agents are stored in separate buildings, 

other than on the premises of makers, 

distributors, and user-compounders of 

explosives or blasting agents, they 

shall be separated from the ammonium 

nitrate by the distances and/or barricades specified in Table H–22 of this 

subpart, but by not less than 50 feet. 

304 

§ 1910.109 29 CFR Ch. XVII (7–1–13 Edition) 

(d) Storage and/or operations on the 

premises of makers, distributors, and 

user-compounders of explosives or 

blasting agents shall be in conformity 

with paragraphs (a) through (h) of this 

section. 

(6) General precautions. (i) Electrical 

installations shall conform to the requirements of subpart S of this part, 

for ordinary locations. They shall be 

designed to minimize damage from corrosion. 

(ii) In areas where lightning storms 

are prevalent, lightning protection 

shall be provided. (See the Lightning 

Protection Code, NFPA 78–1968, which 

is incorporated by reference as specified in §1910.6.) 

(iii) Provisions shall be made to prevent unauthorized personnel from entering the ammonium nitrate storage 

area. 

(7) Fire protection. (i) Not more than 

2,500 tons (2270 tonnes) of bagged ammonium nitrate shall be stored in a 

building or structure not equipped with 

an automatic sprinkler system. Sprinkler systems shall be of the approved 

type and installed in accordance with 

§1910.159. 

(ii)(a) Suitable fire control devices 

such as small hose or portable fire extinguishers shall be provided throughout the warehouse and in the loading 

and unloading areas. Suitable fire control devices shall comply with the requirements of §§1910.157 and 1910.158. 

(b) Water supplies and fire hydrants 

shall be available in accordance with 

recognized good practices. 

(j) Small arms ammunition, small arms 

primers, and small arms propellants—(1) 

Scope. This paragraph does not apply to 

in-process storage and intraplant 

transportation during manufacture of 

small arms ammunition, small arms 

primers, and smokeless propellants. 

(2) Small arms ammunition. (i) No 

quantity limitations are imposed on 

the storage of small arms ammunition 

in warehouses, retail stores, and other 

general occupancy facilities, except 

those imposed by limitations of storage 

facilities. 

(ii) Small arms ammunition shall be 

separated from flammable liquids, 

flammable solids as classified in 49 

CFR part 172, and from oxidizing materials, by a fire-resistive wall of 1-hour 

rating or by a distance of 25 feet. 

(iii) Small arms ammunition shall 

not be stored together with Class A or 

Class B explosives unless the storage 

facility is adequate for this latter storage. 

(3) Smokeless propellants. (i) All 

smokeless propellants shall be stored 

in shipping containers specified in 49 

CFR 173.93 for smokeless propellants. 

(ii) [Reserved] 

(iii) Commercial stocks of smokeless 

propellants over 20 pounds and not 

more than 100 pounds shall be stored in 

portable wooden boxes having walls of 

at least 1 inch nominal thickness. 

(iv) Commercial stocks in quantities 

not to exceed 750 pounds shall be stored 

in nonportable storage cabinets having 

wooden walls of at least 1 inch nominal 

thickness. Not more than 400 pounds 

shall be permitted in any one cabinet. 

(v) Quantities in excess of 750 pounds 

shall be stored in magazines in accordance with paragraph (c) of this section. 

(4) Small arms ammunition primers. (i) 

Small arms ammunition primers shall 

not be stored except in the original 

shipping container in accordance with 

the requirements of 49 CFR 173.107 for 

small arms ammunition primers. 

(ii) [Reserved] 

(iii) Small arms ammunition primers 

shall be separated from flammable liquids, flammable solids as classified in 

49 CFR part 172, and oxidizing materials by a fire-resistive wall of 1-hour 

rating or by a distance of 25 feet. 

(iv) Not more than 750,000 small arms 

ammunition primers shall be stored in 

any one building, except as provided in 

paragraph (j)(4)(v) of this paragraph. 

Not more than 100,000 shall be stored in 

any one pile. Piles shall be at least 15 

feet apart. 

(v) Quantities of small arms ammunition primers in excess of 750,000 shall 

be stored in magazines in accordance 

with paragraph (c) of this section. 

(k) Scope. (1) This section applies to 

the manufacture, keeping, having, 

storage, sale, transportation, and use 

of explosives, blasting agents, and pyrotechnics. The section does not apply 

to the sale and use (public display) of 

pyrotechnics, commonly known as fireworks, nor the use of explosives in the 

305 

Occupational Safety and Health Admin., Labor § 1910.110 

form prescribed by the official U.S. 

Pharmacopeia. 

(2) The manufacture of explosives as 

defined in paragraph (a)(3) of this section shall also meet the requirements 

contained in §1910.119. 

(3) The manufacture of pyrotechnics 

as defined in paragraph (a)(10) of this 

section shall also meet the requirements contained in §1910.119. 

[39 FR 23502, June 27, 1974, as amended at 43 

FR 49747, Oct. 24, 1978; 45 FR 60704, Sept. 12, 

1980; 53 FR 12122, Apr. 12, 1988; 57 FR 6403, 

Feb. 24, 1992; 58 FR 35309, June 30, 1993; 61 FR 

9237, Mar. 7, 1996; 63 FR 33466, June 18, 1998] 

§ 1910.110 Storage and handling of liquefied petroleum gases. 

(a) Definitions applicable to this section. As used in this section: 

(1) API-ASME container—A container constructed in accordance with 

the requirements of paragraph 

(b)(3)(iii) of this section. 

(2) ASME container—A container 

constructed in accordance with the requirements of paragraph (b)(3)(i) of this 

section. 

(3) Container assembly—An assembly 

consisting essentially of the container 

and fittings for all container openings, 

including shutoff valves, excess flow 

valves, liquid-level gaging devices, 

safety relief devices, and protective 

housing. 

(4) Containers—All vessels, such as 

tanks, cylinders, or drums, used for 

transportation or storing liquefied petroleum gases. 

(5) DOT—Department of Transportation. 

(6) DOT container—A container constructed in accordance with the applicable requirements of 49 CFR chapter 1. 

(7) ‘‘Liquified petroleum gases’’— 

‘‘LPG’’ and ‘‘LP-Gas’’—Any material 

which is composed predominantly of 

any of the following hydrocarbons, or 

mixtures of them; propane, propylene, 

butanes (normal butane or iso-butane), 

and butylenes. 

(8) Movable fuel storage tenders or 

farm carts—Containers not in excess of 

1,200 gallons water capacity, equipped 

with wheels to be towed from one location of usage to another. They are basically nonhighway vehicles, but may occasionally be moved over public roads 

or highways. They are used as a fuel 

supply for farm tractors, construction 

machinery and similar equipment. 

(9) P.S.I.G.—pounds per square inch 

gauge. 

(10) P.S.I.A.—pounds per square inch 

absolute. 

(11) Systems—an assembly of equipment consisting essentially of the container or containers, major devices 

such as vaporizers, safety relief valves, 

excess flow valves, regulators, and piping connecting such parts. 

(12) Vaporizer-burner—an integral vaporizer-burner unit, dependent upon 

the heat generated by the burner as the 

source of heat to vaporize the liquid 

used for dehydrators or dryers. 

(13) Ventilation, adequate—when 

specified for the prevention of fire during normal operation, ventilation shall 

be considered adequate when the concentration of the gas in a gas-air mixture does not exceed 25 percent of the 

lower flammable limit. 

(14) Approved—unless otherwise indicated, listing or approval by a nationally recognized testing laboratory. 

Refer to §1910.7 for definition of nationally recognized testing laboratory. 

(15) Listed—see ‘‘approved’’ in 

§1910.110(14). 

(16) DOT Specifications—regulations 

of the Department of Transportation 

published in 49 CFR chapter I. 

(17)–(18) [Reserved] 

(19) DOT cylinders—cylinders meeting the requirements of 49 CFR chapter 

I. 

(b) Basic rules—(1) Odorizing gases. (i) 

All liquefied petroleum gases shall be 

effectively odorized by an approved 

agent of such character as to indicate 

positively, by distinct odor, the presence of gas down to concentration in 

air of not over one-fifth the lower limit 

of flammability. Odorization, however, 

is not required if harmful in the use of 

further processing of the liquefied petroleum gas, or if odorization will serve 

no useful purpose as a warning agent in 

such use or further processing. 

(ii) The odorization requirement of 

paragraph (b)(1)(i) of this section shall 

be considered to be met by the use of 

1.0 pounds of ethyl mercaptan, 1.0 

pounds of thiophane or 1.4 pounds of 

amyl mercaptan per 10,000 gallons of 

LP-Gas. However, this listing of