Cal. Lab. Code § 6720
By January 1, 2019, the division shall propose to the standards board for the board's review and adoption a standard that minimizes heat-related illness and injury among workers working in indoor places of employment. The standard shall be based on environmental temperatures, work activity levels, and other factors. In developing the standard, the division shall take into consideration heat stress and heat strain guidelines in the 2016 Threshold Limit Values and Biological Exposure Indices developed by the American Conference of Governmental Industrial Hygienists. This section does not prohibit the division from proposing, or the standards board from adopting, a standard that limits the application of high heat provisions to certain industry sectors.
Ca. Lab. Code § 6720