State compliance guide, last updated August 2026
Short answer: Cal/OSHA enforces both outdoor (Title 8 §3395) and indoor (Title 8 §3396) heat illness standards. Outdoor protections start at 80°F, indoor at 82°F, with additional 95°F high-heat rules for agriculture, construction, landscaping, oil & gas, and certain transportation.
Direct answer
California does not set a maximum workplace temperature. There is no legal number above which an indoor workplace has to shut down. What section 3396 sets instead are trigger points: once the indoor temperature reaches them, specific controls become mandatory.
| Indoor temperature | What section 3396 requires |
|---|---|
| 82°F | Cool-down area, drinking water, acclimatization, training, emergency response, and a written Indoor Heat Illness Prevention Plan |
| 87°F | All of the above, plus engineering and administrative controls to bring the temperature down, plus measurement and record-keeping |
| 82°F | The 87°F control duties drop to 82°F where clothing restricts heat removal, or in a high radiant heat area (globe temperature at least 5°F above air temperature) |
Section 3396 took effect 23 July 2024 and covers most indoor workplaces in California. Personal cooling is a permitted control under the standard's hierarchy, not a substitute for it. Detail on each requirement is in section 3396 in detail below.
At a glance
Outdoor trigger (§3395)
Outdoor workplaces require water, shade access, training, and an effective heat illness prevention plan.
Indoor trigger (§3396)
Indoor workplaces require water, cool-down areas, training, and a written Indoor Heat Illness Prevention Plan (IHIPP).
High-heat outdoor
Agriculture, construction, landscaping, oil & gas, and transportation face additional observation, break, and communication requirements.
Willful violation ceiling
Cal/OSHA penalties for willful heat-related violations can reach the upper-six-figure range per violation, adjusted periodically.
Sources: California Code of Regulations, Title 8 Section 3395 and Cal/OSHA Heat Illness Prevention.
What the rule actually requires
California runs two rules at once, outdoor and indoor, with different triggers. Work down the tiers that apply to your site.
The indoor rule
| Tier | When it applies | What is required |
|---|---|---|
| 82°F | Indoor temperature reaches or exceeds 82°F while employees are present. | Access to cool drinking water. Cool-down areas maintained below 82°F. Acclimatization procedures for new and returning workers. Training for employees and supervisors. Emergency response procedures. A written Indoor Heat Illness Prevention Plan. |
| 87°F | Temperature or heat index reaches 87°F while employees are present. Also applies at 82°F where employees wear clothing that restricts heat removal, or work in a high radiant heat area. | Everything above, plus assessment and control of the hazard using engineering controls first, then administrative controls, then personal heat-protective equipment. Plus measurement and recordkeeping of temperature and heat index. |
That clothing clause does a lot of work. You are in the 87°F tier from 82°F onward if your people are:
In an unventilated California facility, that is most of the working year.
Written plan
The Indoor Heat Illness Prevention Plan must be in writing, available in English and in the language understood by the majority of employees, and accessible at the worksite. It is the first document an inspector asks for, and a plan nobody on the floor can describe is worse than no plan at all, because it establishes that the hazard was recognized.
Who falls outside it. Section 3396 does not reach everything indoors:
If your exposure genuinely is incidental, write down why. "We assumed it did not apply" is not an assessment.
Where both standards could apply, for example a loading dock that is partly enclosed, the practical approach is to comply with whichever is stricter for that area rather than trying to argue the boundary. For the federal picture and how the enforcement climate is shifting, see the OSHA heat standard and the updated Heat National Emphasis Program. For setting work and rest cycles against measured conditions, the heat index break chart has the risk bands and the escalation rules.
Where cooling vests fit
Cal/OSHA puts engineering and administrative controls first (shade, water, cool-down, work-rest, acclimatization). Cooling vests are supplemental PPE that support a compliant plan, not a substitute for the required infrastructure. The right vest extends safe productive time at and above the 80°F / 82°F triggers.
FAQ
Summer 2026, 500-unit first batch