Blasting and explosives safety

A qualified and trained person who meets employer and regulatory requirements must serve as the blaster.

• The blaster must be trained in the safe use of explosives, firing systems, and emergency procedures, and must follow employer policies and applicable rules found in 1926 Subpart U.
• Employers should document training and qualifications and ensure the blaster understands site-specific hazards, handling, storage, and misfire procedures. See 1926 Subpart U for blasting safety requirements.

All personnel must be cleared from the blast area, a warning given, and a blast plan implemented before firing.

• Establish and enforce a safe evacuation zone and confirm all workers and the public are clear.
• Use an approved warning signal and ensure communication with the firing crew.
• Verify firing circuits and grounding are correct and that all safety checks are complete in accordance with 1926 Subpart U.

A misfire must be treated as live and handled only after waiting the required safe period and following written procedures.

• Keep personnel out of the blast area and post guards until the situation is resolved.
• Follow the employer’s written misfire procedures, which should include waiting times, inspection from a safe location, and safe removal or reinitiation actions.
• Refer to the general blasting safety requirements in 1926 Subpart U for handling misfires.

Explosives must be stored in approved magazines located at safe distances from work, buildings, and public areas and secured against unauthorized access.

• Use magazines designed and constructed for explosive storage and lock them when not in use.
• Follow separation distances and site layout requirements to reduce ignition and casualty risk.
• See the storage and magazine safety requirements described in 1926 Subpart U for details.

Transport of explosives must use approved vehicles or containers, be supervised, and prevent unauthorized access or rough handling.

• Vehicles should be marked, dedicated, or equipped to carry explosives safely and drivers must be trained.
• Avoid transporting explosives near sources of ignition and keep them separate from passengers and incompatible materials.
• Follow transport safety practices consistent with 1926 Subpart U.

Employers must provide adequate training so workers understand hazards, safe handling, storage, firing, and emergency procedures related to explosives.

• Training should be documented and refreshed as needed, and include site-specific procedures, PPE use, and misfire response.
• Ensure trainees demonstrate competency before being assigned blasting duties. See 1926 Subpart U for training-related obligations.

The blasting area must be secured with barricades, warning signs, or guards to prevent unauthorized access until it is safe to re-enter.

• Use physical barriers, posted signs, and assigned personnel to keep the public and nonessential workers out of hazard zones.
• Maintain control of the area from preblast setup until all charges are cleared and declared safe as required by 1926 Subpart U.

Blast crews must wear appropriate PPE such as eye protection, hearing protection, head protection, and other gear based on site hazards.

• PPE selection should match the specific hazards of handling explosives, drilling, and firing operations.
• Employers must provide and enforce PPE use consistent with the hazards outlined in 1926 Subpart U and related PPE standards.

Electric blasting caps may be used but must be handled and wired according to safety procedures to avoid accidental initiation.

• Use insulated firing lines, maintain distance from power sources, and avoid stray currents; follow grounding and circuit control procedures.
• Ensure only qualified personnel connect and test firing circuits as required by 1926 Subpart U.

Firing circuits must be designed, tested, and monitored to prevent accidental initiation from stray currents and electromagnetic interference.

• Use proper insulation, grounding, and circuit testing before connecting to caps; isolate or deactivate nearby power sources during blasting.
• Follow procedures for circuit control, testing, and protection described in 1926 Subpart U.

Blasting near power lines requires coordination to prevent contact or induction hazards and may require de-energizing or insulating lines.

• Coordinate with utility owners to de-energize, relocate, or shield lines when blasting could create hazards.
• Implement additional clearance distances and protective measures consistent with the safety framework in 1926 Subpart U.

Treat any unexploded explosive as live, secure the area, and have only qualified blasters follow established procedures to remove or render it safe.

• Evacuate and control the area until a qualified person assesses and takes corrective action.
• Document the incident and follow reporting and recordkeeping requirements in 1926 Subpart U.

Safe distances and buffer zones must be established based on the type and quantity of explosive, surrounding structures, and potential fragmentation, using accepted blast safety formulas and site assessments.

• Determine evacuation radii and protective measures by evaluating charge weight, ground material, and nearby people or property.
• Employers should document calculations and controls following the hazard mitigation expectations in 1926 Subpart U.

The employer and blasting supervisor must notify affected workers, nearby occupants, and local authorities as needed to ensure public safety before blasting.

• Notifications should include timing, expected effects (noise, vibration), and any necessary access restrictions.
• Coordinate with local emergency responders and follow site-specific communication practices consistent with 1926 Subpart U.

Keep records of training, blaster qualifications, blast plans, magazine inventories, misfires, and incident reports to demonstrate compliance and support investigations.

• Document dates, personnel, amounts of explosives, weather conditions, and any unusual events.
• Maintain these records according to the employer’s program and the safety requirements described in 1926 Subpart U.

Blasting mats or covers should be used when there is a risk of flying debris or fragmentation that could injure people or damage property.

• Use mats, wire mesh, or other restraints where rock throw or flyrock is likely; ensure proper placement and securement by trained personnel.
• Follow protective measures for preventing flyrock and related hazards as expected by 1926 Subpart U.

Magazines must be regularly inspected for structural integrity, moisture, security, and absence of unauthorized items, and maintenance must be documented.

• Repair or remove damaged magazines and ensure proper ventilation and dryness to prevent deterioration of explosives.
• Inspections and maintenance should follow employer procedures consistent with the magazine safety guidance in 1926 Subpart U.

Explosives must be guarded, stored, and handled to prevent access by unauthorized persons and kept away from heat, sparks, open flames, and electrical equipment.

• Use locked magazines, restricted access zones, and clear signage; assign watch personnel when necessary.
• Ensure these control measures are in place as part of the safety program described in 1926 Subpart U.

Have a written emergency plan that provides for immediate first aid, rapid notification of emergency services, site control, and preservation of evidence for investigation.

• Ensure trained personnel and first aid supplies are available, and that evacuation routes are established.
• Emergency planning and response requirements should align with the employer’s blasting safety program found in 1926 Subpart U.

Keep detonators and explosives separate until the last possible moment, avoid rough handling, and ensure only trained personnel perform priming under strict controls.

• Use non-sparking tools, maintain safe distances, and follow written procedures for sequence and timing to reduce the risk of accidental initiation.
• These handling and priming precautions should be implemented consistent with the safety practices in 1926 Subpart U.

Night blasting is allowed if adequate lighting, communication, and control measures are in place to ensure visibility and safety.

• Provide sufficient illumination for work areas, secure perimeters, and ensure all personnel can see hazards and warning signals.
• Follow lighting, notification, and safety procedures appropriate to blasting operations as described in 1926 Subpart U.

Control vibration by limiting charge size, optimizing blast design, and using stemming, mats, or delay sequences to reduce peak particle velocity and structural risk.

• Preblast surveys, monitoring during blasting, and postblast inspections help assess and mitigate damage.
• Implement blast design and monitoring strategies consistent with protective expectations in 1926 Subpart U.

Contractors must coordinate schedules, control zones, and communications so that all trades know blasting times, evacuation procedures, and safe re-entry conditions.

• Conduct preblast briefings, issue written plans, and assign a single blasting supervisor to manage interfaces with other crews.
• Coordination practices should reflect the site safety program requirements in 1926 Subpart U.

Prevent accidental ignition by using non-sparking tools, controlling friction and impact risks, grounding equipment, and minimizing electrostatic buildup.

• Use conductive clothing or grounding straps where static discharge is a hazard and store explosives away from sources of mechanical impact.
• These preventive measures should be part of the handling and storage procedures required under 1926 Subpart U.

Disposal of surplus or damaged explosives must be done by qualified personnel according to approved procedures, which may include returning to manufacturer, authorized destruction, or controlled detonation.

• Never bury, burn, or otherwise dispose of explosives casually; document disposal actions and coordinate with authorities as required.
• Follow disposal and handling controls that are part of the safety program in 1926 Subpart U.

A blast plan should identify the blaster in charge, charge sizes and placement, evacuation zones, warning procedures, magazine locations, misfire plans, and emergency contacts.

• Include maps, timing sequences, environmental controls, and monitoring procedures for vibration and flyrock.
• Keep the blast plan available and enforce it as part of the operational requirements under 1926 Subpart U.