30 CFR § 56.6310
Misfire waiting period
July 29, 2020
When a misfire is suspected, persons shall not enter the blast area—
(a) For 30 minutes if safety fuse and blasting caps are used;
(b) For 15 minutes if any other type detonators are used; or
(c) For 30 minutes if electronic detonators are used, or for the manufacturer-recommended time, whichever is longer.
[61 FR 36795, July 12, 1996, as amended at 85 FR 2027, Jan. 14, 2020]