General explosives provisions

Only authorized and qualified persons may handle and use explosives on a construction site. See the requirement in 1926.900(a).

• "Authorized and qualified" means the employer must limit handling to people who have the training, experience, and permission to work with explosives.
• Keep records of who is authorized and provide site-specific training and supervision.

Smoking, firearms, matches, open-flame lamps, and any fires, flame- or heat-producing devices or sparks must be prohibited in or near magazines and whenever explosives are being handled, transported, or used. See 1926.900(b).

• Post reminders and train workers about the ban.
• Enforce a no-smoking policy and control ignition sources during handling and transport.

No; no person may handle or use explosives while under the influence of intoxicating liquors, narcotics, or other dangerous drugs. See 1926.900(c).

• Employers should establish and enforce policies to prevent impaired persons from handling explosives, including training and supervision.

Explosives must be accounted for at all times; when not in use they must be kept in a locked magazine and unavailable to unauthorized persons, and the employer must maintain an inventory and use record and notify authorities of any loss, theft, or unauthorized entry. See 1926.900(d).

• Maintain a current inventory log showing receipts, issues, and remaining quantities.
• Use locked magazines and control keys/access.
• Immediately notify appropriate authorities of loss/theft/unauthorized entry.

No; explosives and blasting agents may not be abandoned. See 1926.900(e).

• Plan for removal or secure storage at the end of each shift or project phase to avoid abandonment.

No; if a fire is in imminent danger of contacting explosives, it must not be fought—employees should be removed to a safe area and the fire area guarded against intruders. See 1926.900(f).

• Evacuate and secure the area; notify emergency responders and authorities trained to handle fires involving explosives.

Detonators and other explosives must be transported from storage to the blasting area in original containers or Class II magazines. See 1926.900(g).

• Use proper containers to protect from shock, friction, and static; never carry loose detonators in pockets.

When blasting near structures, railways, highways, or other installations that may be damaged, the blaster must take special precautions in loading, delaying, initiation, and confinement (for example using mats) to control fragments and prevent bodily injury. See 1926.900(h).

• Conduct a pre-blast hazard assessment, use mats or confinement methods, and plan delays/charges to minimize flyrock and vibration.

Employees authorized to prepare charges or conduct blasting operations must use every reasonable precaution, including visual and audible warning signals, flags, or barricades, to ensure employee safety. See 1926.900(i).

• Use clear warning signals, maintain lookout personnel, and establish exclusion zones with barricades and signage before firing.

As far as possible, above-ground blasting operations should be conducted between sunup and sundown. See 1926.900(j).

• Daylight operations improve visibility for safety and the effectiveness of warning signals and lookouts.

Due precautions must be taken to prevent accidental discharge of electric blasting caps from currents induced by radar, radio transmitters, lightning, adjacent powerlines, dust storms, or other extraneous electricity. See 1926.900(k).

Key precautions include:

• Short-circuiting and shunting primed holes until wired into the blasting circuit (1926.900(k)(1)).
• Suspending blasting and clearing the area during electric storms (1926.900(k)(2)).
• Posting signs warning against mobile radio transmitters within 1,000 feet and, if 1,000 feet is impractical, documenting competent-person alternatives in writing (1926.900(k)(3)(i)).
• Deenergizing and locking mobile radio transmitters within 100 feet of caps when not in original containers (1926.900(k)(4)).

Detonators in primed holes must be short-circuited and shunted until they are wired into the blasting circuit. See 1926.900(k)(1).

• Use approved shorting devices and follow manufacturer instructions to prevent unintended initiation from stray currents.

All blasting operations must be suspended and all persons removed from the blasting area during the approach and progress of an electric storm. See 1926.900(k)(2).

• Monitor weather and clear the area early—do not wait until lightning is visible or imminent.

Prominent signs warning against the use of mobile radio transmitters must be displayed on all roads within 1,000 feet of blasting operations; if the 1,000-foot distance causes operational hardship, a competent person may design alternatives, and the written description of those alternatives must be kept at the site and be available for OSHA inspection. See 1926.900(k)(3)(i).

• Keep the competent person’s written evaluation on site for inspection.
• Use the specimen signs shown in 1926.900(k)(3)(ii) as guidance.

Mobile radio transmitters that are less than 100 feet away from electric blasting caps (when the caps are not in original containers) must be deenergized and effectively locked. See 1926.900(k)(4).

• Implement lockout procedures and ensure radios cannot be turned on accidentally during blasting operations.

Employers must comply with the recommendations of The Institute of the Makers of Explosives in IME Publication No. 20 regarding radio frequency hazards and electric blasting caps. See 1926.900(k)(5).

• Consult IME Publication No. 20 for technical guidance on safe distances and mitigation when blasting near radio transmitters.

No; empty boxes and paper and fiber packing that previously contained high explosives must not be reused and must be destroyed by burning at an approved location. See 1926.900(l).

• Destroy packing safely and document the disposal method to prevent accidental re-use.

No; explosives, blasting agents, and blasting supplies that are obviously deteriorated or damaged must not be used. See 1926.900(m).

• Inspect all materials before use and remove damaged items for safe disposal.

Delivery and issue of explosives must be made only by and to authorized persons and only into authorized magazines or approved temporary storage/handling areas. See 1926.900(n).

• Verify identity of recipients and document each transfer; keep deliveries to authorized storage areas.

Before blasting near overhead power lines, communication lines, utilities, or other services and structures, the operators and/or owners must be notified and measures for safe control must be taken. See 1926.900(o).

• Coordinate with utility owners to de-energize, shield, or otherwise protect lines; document the agreed control measures.

No; the use of black powder is prohibited. See 1926.900(p).

• Use approved modern explosives and adhere to manufacturer and regulatory guidance.

All loading and firing must be directed and supervised by competent persons who are thoroughly experienced in blasting. See 1926.900(q).

• Maintain documentation of the competent person’s qualifications and ensure they are present for critical operations.

Blasts must be fired electrically with an electric blasting machine or a properly designed electric power source, except as provided in 1926.906. See 1926.900(r).

• Review 1926.906 for authorized non-electric firing methods and any specified conditions or exceptions.

Buildings used for mixing blasting agents and water gels must be noncombustible or sheet metal on wood studs, have nonabsorbent (e.g., concrete) floors, be well ventilated, separate fuel-oil storage so spills drain away, and use noncombustion heating units or ensure direct heat sources are located outside the building; internal-combustion engines for power must be outside or isolated by a firewall with exhausts placed to avoid sparks. See 1926.900(s) and 1926.900(t).

• Ensure mixing plants meet the listed separation, ventilation, flooring, and heating/engine-location requirements.

Internal-combustion engines used for electric power in mixing plants must be located outside the building or be properly ventilated and isolated by a firewall, with exhaust systems positioned to prevent spark hazards to materials in or adjacent to the plant. See 1926.900(s)(6) and 1926.900(t)(6).

• Position exhausts to prevent sparks from reaching flammable or explosive materials and inspect engines regularly.

Yes; 1926.900(k)(3)(ii) includes specimen signs (for example, "Blasting Zone 1000 ft" and "Turn Off 2 Way Radio") that would meet the paragraph (k)(3) requirements and employers may use these designs as guidance. See 1926.900(k)(3)(ii).

• Use clear, prominent signage on access roads within required distances and ensure signs remain visible throughout blasting operations.