30 CFR § 57.6500
Damaged initiating material.
NONELECTRIC BLASTING--SURFACE AND UNDERGROUND
A visual check of the completed circuit shall be made to ensure that the
components are properly aligned and connected. Safety fuse, igniter cord,
detonating cord, shock or gas tubing, and similar material which is kinked,
bent sharply, or damaged shall not be used.
[58 FR 69596, Dec. 30, 1993]