Detonating cord handling requirements

Under 1926.908(a), you must select a detonating cord that matches the bore hole conditions, stemming, and the explosives you are using.

• Consider the diameter and depth of the bore hole, the type and tightness of stemming, and the sensitivity and velocity of the explosive charge.
• Use a cord with a core load and construction recommended for the explosives and bore-hole environment.

See the OSHA requirement in 1926.908(a) for the selection obligation.

Under 1926.908(b), detonating cord must be handled and used with the same respect and care given to other explosives.

• Treat cord as an explosive item: store, transport, and handle it per established explosive safety practices.
• Keep cord away from heat, impact, friction, and sources of ignition; follow your employer's explosives safety rules and manufacturer's instructions.

See the OSHA requirement in 1926.908(b).

Under 1926.908(c), you must cut the line of detonating cord that extends out of a bore hole from the supply spool before you finish loading the remainder of the bore hole or place additional charges.

• Cutting the line frees the loaded section from the supply spool so additional handling won't tug or stress the cord in the loaded hole.
• Use tools and methods that avoid damaging the cord when cutting.

See the OSHA requirement in 1926.908(c).

Under 1926.908(d), detonating cord must be handled and used with care, and if you damage a cord you should not use the damaged section; replace it with undamaged cord.

• Remove and replace any cord that is nicked, crushed, abraded, or severed.
• Do not attempt to splice or repair a damaged explosive core unless using approved methods by the manufacturer or an accepted industry practice.

See the OSHA requirement in 1926.908(d).

Under 1926.908(e), knot-type or other cord-to-cord connections are allowed only when the detonating cord's explosive core is dry, and all connections must be competent and positive.

• Only make knot-type connections with dry-cored cord because moisture can prevent reliable transfer of detonation.
• Prefer approved connectors or recommended methods when available, and ensure every connection is tight and secure.

See the OSHA requirement in 1926.908(e).

Under 1926.908(e), a "competent and positive" detonating cord connection means the joint must reliably transmit detonation and be made using approved or recommended methods.

• Use manufacturer-recommended connectors, secure mechanical splices, or properly tied knots (only with dry core).
• Avoid loose, poorly aligned, or improvised joints that might fail to transfer detonation.

See the OSHA requirement in 1926.908(e).

Under 1926.908(f), all detonating cord trunklines and branchlines must be routed free of loops, sharp kinks, or angles that would direct the cord back toward the oncoming line of detonation.

• Lay cord straight and without tight bends; avoid configurations that could reflect or redirect a detonation into oncoming cord.
• Secure cord to prevent movement into hazardous angles during loading or prior to firing.

See the OSHA requirement in 1926.908(f).

Under 1926.908(g), you must inspect all detonating cord connections before firing to ensure they are secure, properly made, and undamaged.

• Check that connectors or knots are tight and correctly oriented, the explosive core is intact and dry where required, and the cord shows no nicks, abrasions, or cuts.
• Verify that trunklines and branchlines are free of loops, kinks, and unsafe angles and that caps/connectors are attached per instruction.

See the OSHA requirement in 1926.908(g).

Under 1926.908(h), the use of millisecond-delay connectors or short-interval-delay electric blasting caps with detonating cord must strictly conform to the manufacturer's recommendations.

• Follow the manufacturer's installation, handling, and sequencing instructions exactly for safety and reliable performance.
• Do not improvise or alter connector/cap use beyond what the manufacturer specifies.

See the OSHA requirement in 1926.908(h).

Under 1926.908(i), when connecting a blasting cap or electric blasting cap to detonating cord, attach the cap securely along the side or end of the cord with the cap end containing the explosive charge pointed in the direction you want the detonation to proceed.

• Tape or otherwise fasten the cap so it cannot move or pull away; confirm the orientation so the explosive faces toward the intended detonation path.
• For electric caps, ensure any leads are routed and protected per manufacturer's instructions to avoid accidental damage or shorting.

See the OSHA requirement in 1926.908(i).

Under 1926.908(j), detonators for firing the trunkline must not be brought into the loading area or attached to the detonating cord until everything else is ready for the blast.

• Keep detonators separate and secure until final preparations are complete to minimize the chance of accidental initiation.
• Only after all loading, stemming, connections, and safety checks are finished should detonators be brought in and attached immediately before firing.

See the OSHA requirement in 1926.908(j).

Under 1926.908(d) and (b), practical steps to avoid damaging detonating cord include handling it gently, using appropriate cutting tools, and keeping it away from sharp edges, heavy machinery, and sources of heat.

• Unspool cord slowly and support it to avoid kinks or abrasion.
• Use sheathing or protective tubing where the cord passes over rough surfaces.
• Train workers to recognize damaged cord and to remove/replace any compromised sections immediately.

See the OSHA requirements in 1926.908(d) and 1926.908(b).

Under 1926.908(f), trunklines must be free of loops or kinks that could direct the cord back toward the oncoming detonation to prevent unintended re-entrant detonation paths or sympathetic initiation of adjacent charges.

• Loops or return angles can cause the detonation wave to travel in undesired directions, increasing the risk of premature or uncontrolled initiation.
• Laying cord straight and securing it reduces risk and ensures predictable propagation.

See the OSHA requirement in 1926.908(f).

Under 1926.908(e) and 1926.908(g), inspect that the explosive core is dry, the knot is tight and properly dressed, the cord jackets are not cut or crushed at the knot, and the connection aligns with intended detonation direction.

• Verify dryness of the core (moisture can prevent detonation transfer).
• Check for movement, looseness, or exposed core material that could indicate an unreliable joint.

See the OSHA requirements in 1926.908(e) and 1926.908(g).

Under 1926.908(i), the end of the blasting cap that contains the explosive charge must be pointed in the direction in which the detonation is to proceed.

• Secure the cap along the side or end of the cord so the explosive end faces toward the next segment or charge you intend to initiate.
• Proper orientation helps ensure predictable and reliable detonation propagation.

See the OSHA requirement in 1926.908(i).

Under 1926.908(h), you must follow the manufacturer's recommendations for millisecond-delay connectors or short-interval-delay electric blasting caps even if they differ from your usual practice.

• Stop and reconcile any differences: use the manufacturer's specified methods for installation and sequencing to remain compliant and safe.
• If the instructions are unclear, contact the manufacturer for clarification before proceeding.

See the OSHA requirement in 1926.908(h).

Under 1926.908(b)–(j), workers should be trained to handle detonating cord with the same respect as other explosives, including selection, cutting procedures, avoiding damage, proper connection methods, inspection before firing, correct cap attachment, and the rule about not bringing detonators into the loading area until ready.

• Train on safe unspooling, cutting from the supply spool per 1926.908(c), preventing damage 1926.908(d), and secure connections 1926.908(e).
• Ensure workers know to inspect all connections before firing (1926.908(g)) and to comply with manufacturer's directions for delay devices (1926.908(h)).

Under 1926.908(e), the standard requires connections be "competent and positive" and made by approved or recommended methods, which allows alternatives to knot-type connections if they are manufacturer's or industry-approved.

• Use manufacturer-recommended mechanical connectors or approved detonating-cord connectors when available, as these often provide more reliable performance than knots.
• Any chosen method must securely transmit detonation and meet the approved/recommended guidance.

See the OSHA requirement in 1926.908(e).

Under 1926.908(j) and related provisions, reduce accidental initiation risk by keeping detonators out of the loading area until everything else is ready, handling cord carefully to avoid damage, inspecting all connections before firing, and following manufacturer's instructions for delay devices.

• Keep detonators stowed separately and secure until final hookup (1926.908(j)).
• Avoid rough handling, sharp bends, or pinched sections of cord (1926.908(d) and (f)).
• Inspect every connection and cap orientation before firing (1926.908(g) and (i)).

Under 1926.908(e), you must not make knot-type cord-to-cord connections if the explosive core is wet; dry or replace the cord before making knot connections or use approved connectors that accommodate damp conditions.

• If moisture is present, replace with dry cord or consult the manufacturer for acceptable connection methods; do not rely on knots in wet cores.
• Inspect for moisture during pre-fire checks and act accordingly.

See the OSHA requirement in 1926.908(e).