What does California require for outdoor crews in the heat?

Heat illness is regulated by specific numbers rather than by a general duty to be careful, which is unusual and helpful: an employer can tell whether they comply without interpreting anything.

Water must be fresh, pure, suitably cool and free, in a quantity sufficient to provide one quart per employee per hour for the entire shift — and it must be located as close as practicable to where employees are working.

Shade must be present when the temperature exceeds 80°F, sufficient to accommodate the number of employees on rest or recovery, and employees must be allowed and encouraged to take a preventative cool-down rest when they feel the need. That rest is not less than five minutes, and an employee may not be ordered back to work until symptoms have abated. At 95°F and above, high-heat procedures apply, adding observation, communication and pre-shift meeting requirements; agricultural employees at that temperature get a mandatory ten-minute cool-down every two hours.

The plan itself is a document, not an intention. It must be established, implemented and maintained in writing, in English and in the language understood by the majority of the employees, and be available at the worksite. Cal/OSHA also adopted an indoor heat standard, so an employer whose crews move between a yard and a warehouse should not assume the outdoor rule is the only one that applies.