California Code, Labor Code - LAB § 6710

(a) At every place of employment where explosives are used in the course of employment, there shall be a person licensed pursuant to the provisions of Chapter 3 (commencing with Section 7990) of Part 9 of Division 5, to supervise and visually direct the blasting operation.

(b) For the purposes of this section, “explosives” shall include, but not be limited to, class A and B explosives, blasting caps, detonating cord, and charges or projectiles used in the control of avalanches. For the purposes of this section, “explosives” shall not include small arms ammunition or class C explosives such as explosive powerpacks in the form of explosive cartridges or explosive-charged construction devices, explosive rivets, bolts, and charges for driving pins and studs, and cartridges for explosive-actuated power devices.

(c) This section shall not apply to persons, firms, or corporations licensed pursuant to Part 2 (commencing with Section 12500) of Division 11 of the Health and Safety Code.