California Code, Health and Safety Code - HSC § 25913

(a)(1) The Division of Occupational Safety and Health of the Department of Industrial Relations shall enforce this chapter with respect to the safety of employees as provided in Part 1 (commencing with Section 6300) of Division 5 of the Labor Code.

(2) However, the Division of Occupational Safety and Health shall be responsible for the enforcement of subdivision (b) of Section 25910 only with respect to the manufacture of the substances described there, only when workers are handling such substances, and only if the division or any employee or agent of the division becomes aware of such manufacture. Furthermore, in such cases, the division shall enforce subdivision (b) of Section 25910 by issuing an order prohibiting use or entry, pursuant to the procedure described in Sections 6325 to 6327, inclusive, of the Labor Code, regardless of whether there exists employee exposure, a dangerous condition, improper guarding, dangerous placement, or an imminent hazard, and at any hearing concerning the validity of such an order, no proof need be tendered by the division concerning employee exposure, dangerous condition, improper guarding, dangerous placement, or imminent hazard.