As temperatures rise across California, employers should revisit their obligations under Cal/OSHA’s heat illness prevention standards. California continues to regulate both outdoor and indoor heat exposure, and those requirements remain important in 2026. By contrast, federal OSHA still has not issued a final nationwide heat-specific standard. OSHA’s proposed rule, Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings, was published in August 2024, and the agency’s public hearing process concluded in 2025, but the rule has not yet been finalized.
For California employers, the outdoor heat illness prevention standard applies to all outdoor places of employment. Among other things, employers must provide fresh drinking water, access to shade, cool-down rest opportunities, training, emergency response procedures, and acclimatization procedures. California’s outdoor rule also requires high-heat procedures in certain industries, and additional precautions apply when temperatures reach 95°F or higher.
California employers also need to remember that the state’s indoor heat standard, which took effect on July 23, 2024, remains in force in 2026. The indoor rule generally applies to workplaces where the temperature reaches 82°F, requiring employers to provide water, cool-down areas, training, emergency response procedures, and acclimatization measures. Additional monitoring and control measures are required when the temperature or heat index reaches 87°F, or at 82°F in certain circumstances, such as where employees wear heat-retaining clothing or work in high radiant heat areas.
Covered employers must have written Indoor/Outdoor Heat Illness Prevention Plans and ensure the Plans are implemented and followed. Employers with both indoor and outdoor operations should evaluate each work area separately. In practice, that means reviewing whether current written procedures, supervisor training, employee training, water access, cool-down areas, temperature-monitoring practices, and emergency response protocols satisfy the requirements of both Section 3395 and Section 3396. Cal/OSHA also continues to emphasize heat illness prevention through guidance and outreach in 2026, underscoring that this remains an active compliance issue for California employers.
California employers cannot wait for a federal rule before acting. Even though federal OSHA has not yet adopted its own final heat injury regulation, California employers already must comply with the state’s established indoor and outdoor heat illness prevention standards.
