29 CFR 1926.909 Firing the blast

§ 1926.909

29 CFR Ch. XVII (7–1–04 Edition)

area nor attached to the detonating
cord until everything else is in readiness for the blast.
§ 1926.909 Firing the blast.
(a) A code of blasting signals equivalent to Table U–1, shall be posted on
one or more conspicuous places at the
operation, and all employees shall be
required to familiarize themselves with
the code and conform to it. Danger
signs shall be placed at suitable locations.
(b) Before a blast is fired, a loud
warning signal shall be given by the
blaster in charge, who has made certain that all surplus explosives are in a
safe place and all employees, vehicles,
and equipment are at a safe distance,
or under sufficient cover.
(c) Flagmen shall be safely stationed
on highways which pass through the
danger zone so as to stop traffic during
blasting operations.
(d) It shall be the duty of the blaster
to fix the time of blasting.
(e) Before firing an underground
blast, warning shall be given, and all
possible entries into the blasting area,
and any entrances to any working
place where a drift, raise, or other
opening is about to hole through, shall
be carefully guarded. The blaster shall
make sure that all employees are out
of the blast area before firing a blast.
TABLE U–1
WARNING SIGNAL—A 1-minute series of long
blasts 5 minutes prior to blast signal.
BLAST SIGNAL—A series of short blasts 1
minute prior to the shot.
ALL CLEAR SIGNAL—A prolonged blast following the inspection of blast area.

§ 1926.910 Inspection after blasting.
(a) Immediately after the blast has
been fired, the firing line shall be disconnected from the blasting machine,
or where power switches are used, they
shall be locked open or in the off position.
(b) Sufficient time shall be allowed,
not less than 15 minutes in tunnels, for
the smoke and fumes to leave the
blasted area before returning to the
shot. An inspection of the area and the
surrounding rubble shall be made by
the blaster to determine if all charges
have been exploded before employees
are allowed to return to the operation,

and in tunnels, after the muck pile has
been wetted down.
§ 1926.911 Misfires.
(a) If a misfire is found, the blaster
shall provide proper safeguards for excluding all employees from the danger
zone.
(b) No other work shall be done except that necessary to remove the hazard of the misfire and only those employees necessary to do the work shall
remain in the danger zone.
(c) No attempt shall be made to extract explosives from any charged or
misfired hole; a new primer shall be
put in and the hole reblasted. If refiring of the misfired hole presents a
hazard, the explosives may be removed
by washing out with water or, where
the misfire is under water, blown out
with air.
(d) If there are any misfires while
using cap and fuse, all employees shall
remain away from the charge for at
least 1 hour. Misfires shall be handled
under the direction of the person in
charge of the blasting. All wires shall
be carefully traced and a search made
for unexploded charges.
(e) No drilling, digging, or picking
shall be permitted until all missed
holes have been detonated or the authorized representative has approved
that work can proceed.
§ 1926.912 Underwater blasting.
(a) A blaster shall conduct all blasting operations, and no shot shall be
fired without his approval.
(b) Loading tubes and casings of dissimilar metals shall not be used because of possible electric transient currents from galvanic action of the metals and water.
(c) Only water-resistant blasting caps
and detonating cords shall be used for
all marine blasting. Loading shall be
done through a nonsparking metal
loading tube when tube is necessary.
(d) No blast shall be fired while any
vessel under way is closer than 1,500
feet to the blasting area. Those on
board vessels or craft moored or anchored within 1,500 feet shall be notified before a blast is fired.
(e) No blast shall be fired while any
swimming or diving operations are in
progress in the vicinity of the blasting

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