What Is 8 CCR §3396: Indoor Heat Illness Prevention?

This section applies to all indoor work areas where the temperature equals or exceeds 82 degrees Fahrenheit when employees are present.

What is 8 CCR §3396?

Section 3396 is Cal/OSHA’s indoor heat rule, starting with basic duties at 82 degrees and adding stronger controls once it is hotter or conditions are worse.

The rule reaches any indoor workplace, warehouses, kitchens, manufacturing floors, and similar spaces, where the temperature hits 82 degrees Fahrenheit while employees are there. A narrower set of duties, engineering and administrative controls and protective gear, applies once the actual temperature or the heat index reaches 87 degrees, or once it reaches 82 degrees for workers who wear heat-trapping clothing or work near a strong radiant heat source, such as an oven or a furnace. California lawmakers told Cal/OSHA to write an indoor heat standard back in 2016; Labor Code section 6720 set a goal of 2019, though the finished rule did not take effect until 2024.

What must your employer give you once it hits 82 degrees?

Cool water nearby and a cool-down space kept under 82 degrees, sized for everyone who needs a break.

Once an indoor work area reaches 82 degrees while you are there, your employer must give you free, cool water, about one quart per hour, and set up one or more cool-down areas you can reach quickly. Those spaces must fit everyone on a break without anyone having to touch another person, and their own temperature must stay under 82 degrees unless the employer shows that is not possible. You can step into the cool-down area any time you feel the need to, and your employer must let you stay there until your symptoms clear, plus at least five more minutes.

What extra controls apply once it is hotter, or the job traps heat?

Employers must try better airflow or cooling first, then schedule changes, and use protective gear only as a last resort.

The rule sets an order of controls, not a free choice. Engineering controls, such as fans, air conditioning, or shielding from a heat source, come first, aimed at keeping the area under 87 degrees, or under 82 degrees for workers in heat-trapping clothing or near strong radiant heat. If engineering controls cannot get there alone, the employer turns to administrative controls: rotating workers, moving tasks to cooler hours, shortening shifts, or adding rest breaks. Personal protective equipment, such as a cooling vest, is the last resort, used only once the other two steps still do not solve the problem.

What does "acclimatization" mean under this rule?

New workers need time for their bodies to adjust to heat, so a supervisor must watch them more closely at first.

If you are new to a hot indoor job, or coming back after time away from it, your body has not yet adjusted to the heat. The rule calls this acclimatization. For your first two weeks on a job covered by the stronger control measures, a supervisor or someone your employer picks must keep a closer eye on you, since new and returning workers face a higher risk of heat illness in that early stretch.

Does this rule ever not apply?

Yes. Short exposures, home-based telework, true emergencies, and certain detention facilities fall outside it.

The rule does not reach work done from a location you chose yourself, outside your employer’s control. It does not reach a brief trip into a hot area, under 15 minutes in any 60-minute stretch, as long as the area stays below 95 degrees. That exception does not cover a vehicle without working air conditioning, or loading or unloading a shipping container. It also does not reach emergency work to protect life or property, or certain state prisons, local jails, and juvenile facilities. Outside those narrow situations, the rule applies.

What should you do if your workplace ignores this rule, or you get sick anyway?

Report it to Cal/OSHA, write down what happened, and remember that workers’ comp pays for a heat illness either way.

If your workplace has no cool-down area, will not fix the heat, or punishes you for raising it, you can report it to Cal/OSHA by phone or by email, and you do not need to know the exact rule number before you call. Note the approximate temperature, what was missing, and the date; that record can help later. Firing or disciplining a worker for raising a heat complaint is against the law, and where conditions are truly unsafe, California law also lets you refuse work that would violate a safety standard like this one.

A heat illness claim itself does not turn on whether this rule was followed; California workers’ comp is no-fault either way. The medical care and wage rules are the same for every heat claim; this site’s heat illness claim guide walks through them in full. Warehouse and kitchen crews run into this rule often: a warehouse injury guide and a fast food injury guide both cover jobs where this indoor standard applies. A known, ignored violation can still matter for an added claim under the broader Cal/OSHA safety duty behind it.

What should you do after an indoor heat illness?

See a doctor right away. After that, write down the indoor temperature if you remember it, whether a cool-down spot was close by, and what your supervisor said when you raised it. If indoor heat has already made you or a family member sick, call (661) 273-1780 or use the contact form for a free review. Eman Yazdchi represents California workers hurt by indoor heat from a single Palmdale office, and reviews each matter individually.