When §3396 Triggers: 82°F and 87°F

The indoor standard has two temperature thresholds that drive different requirements.

• 82°F indoor temperature. This is the trigger for the core plan: water provision, cool-down area access, employee acclimatization procedures, training, and emergency response. If any indoor work area regularly reaches 82°F, you need a written plan that addresses that area.
• 87°F temperature or heat index. At 87°F, the full assessment and “heat control measures” apply. These are administrative or engineered controls to reduce the heat exposure: increased rest, rotation, work-rest schedules, fans, evaporative cooling, or other measures appropriate to the work. The same full requirements also apply at 82°F in two situations: where employees wear clothing that restricts heat removal, or where they work in a high radiant heat area.

The standard applies to all indoor work areas that reach 82°F while employees are present. There is a narrow exception for incidental exposure: employees exposed at or above 82°F and below 95°F for less than 15 minutes in any 60-minute period. That exception does not apply to vehicles without working air conditioning, or to shipping or intermodal containers during loading, unloading, or related work. This incidental-exposure exception is the most-missed detail when facilities scope their indoor plan. Applied correctly, it can reduce the number of monitored areas; applied wrong, it leaves out areas an inspector will say should have been covered.

Ready to build the plan? What a real §3395/§3396 heat illness plan template contains →

What §3396 Requires: A Quick Implementation Checklist

A working indoor heat illness program in California needs the following:

• A written plan specific to your facility, in English and in the language understood by the majority of workers
• Procedures for water: at least one quart per employee per hour, available throughout the shift; electrolyte or sports drinks may be offered as a supplement but do not replace the required potable water
• Cool-down area kept below 82°F, shielded from direct sunlight and high-radiant-heat sources, sized for the employees who might use it at one time, located close enough to be practical
• Temperature and heat index measurement procedures: which areas are monitored, by whom, how often, and how the data is recorded
• Heat control measures identified in advance for areas that reach 87°F (and for areas at 82°F where employees wear heat-restrictive clothing or work in high radiant heat), with the trigger and implementation tied to specific work areas
• Acclimatization procedures for new employees and for everyone during heat waves
• Emergency response procedures: how heat illness is recognized, who is contacted, how emergency medical services are summoned and directed to the affected employee
• Training for employees and supervisors before any exposed employee starts work
• Recordkeeping for training, temperature monitoring, and any heat-related incidents

Cal/OSHA evaluates both the content of the plan and how it is presented. A plan that lists thresholds without naming specific work areas, supervisors, or response procedures rarely holds up under inspection.

Where Warehouses and Manufacturers Typically Have Gaps

When we walk a Central Valley warehouse or an inland manufacturing facility for the first time, the temperature is rarely the issue. By two in the afternoon in August, many of these buildings are clearly over 82°F, and parts of them are over 87°F. The gaps are almost always in how the plan handles the work.

The most common issues we find:

• No temperature data. The facility knows it gets hot but has never measured. Cal/OSHA expects measured temperatures tied to specific areas, not impressions. We typically recommend a combination thermometer/hygrometer device in each monitored area, with historical data logging, so the facility can show actual readings over time.
• Cool-down area in the wrong place. A break room used as the cool-down area, but the break room is on the second floor with no air conditioning, or it is on the south side of the building with afternoon sun on a metal roof. The regulation requires the area to be below 82°F and shielded from radiant heat sources. Location matters.
• Heat control measures named but not triggered. The plan says “fans will be used at 87°F” but no one is measuring, no one knows who turns them on, and the fans are stored in a back room. Heat control measures have to be tied to a temperature trigger, a person responsible, and an actual implementation.
• One plan for a multi-zone facility. A 200,000-square-foot warehouse with a chilled section, a dry storage section facing south, and a packing operation with sealing equipment is not one heat environment. The areas heat up differently and may need different control measures. The plan has to reflect that.
• Indoor plan missing from a pre-2024 IIPP. Any IIPP written before July 2024 was almost certainly built around the outdoor standard, §3395. The indoor requirements are not in it. This is the single most common gap we find. For how the plan attaches to your overall safety program, see your IIPP’s heat illness appendix.

Heat Control Measures at 87°F: What Counts

The rule does not prescribe specific equipment. It requires the employer to identify and implement administrative or engineering controls that reduce exposure. (The same control obligation is triggered at 82°F where employees wear heat-restrictive clothing or work in a high-radiant-heat area.) In a warehouse or manufacturing context, that typically looks like one or more of:

• Industrial fans positioned for direct airflow on workers
• Evaporative coolers in fixed work areas
• Increased rest cycles in cool-down areas
• Rotation of employees through hotter and cooler work areas
• Shifted schedules so the hottest work happens earlier in the day
• Engineering changes: insulating roll-up doors, adding white roofing, isolating process heat sources, adding spot cooling at workstations

Whatever you pick has to actually be used when temperatures cross 87°F, and that requires a supervisor who is measuring and who has the authority to implement the measure. A binder that lists controls without an assigned person does not hold up.

Training Before Exposure Starts

§3396 requires training before an employee starts work with potential exposure. The training covers heat illness risk factors, the importance of water and acclimatization, the signs and symptoms of heat illness, how to report symptoms, how to respond, and how to contact emergency services. Supervisors need additional training on recognizing symptoms and on implementing the heat control measures.

For California facilities with bilingual workforces, training has to be delivered in the language the majority of workers understand. We deliver indoor heat illness training in English and Spanish.

Where the Indoor Plan Lives

The indoor heat illness plan can be a standalone document or an appendix to the IIPP. Cal/OSHA permits either. What matters is that the plan is written, specific to the facility, and accessible. The plan does not get “filed” with Cal/OSHA. It lives on site and gets produced when an inspector asks for it.

If you already have an IIPP and are adding indoor heat illness for the first time, this is also the moment to review the rest of the IIPP. Most pre-2024 IIPPs have the outdoor heat illness elements at best and no indoor heat illness procedures at all.