September in California can be one of the hottest times of the year (September Heat Alert).  Workplace protective measures against high temperature protections are a priority.

Heat illnesses range from mild to deadly. The two most serious are: heat exhaustion (including dizziness, headache, sweaty skin, fast heartbeat, nausea, vomiting and cramping); and heat stroke (including red, hot dry skin, high body temperature, muscle twitching, confusion, fainting, convulsions and unconsciousness).

Employers with outdoor workers must have an effective written heat illness prevention plan, following Cal/OSHA’s six protective measures:

• Observe - Closely observe all employees during a heat wave, especially those newly assigned to a high heat area, and provide lighter work, frequent breaks or shorter hours to help acclimate;
• Train - Train all employees and supervisors on heat illness prevention;
• Water - Provide at least one quart per hour of free, cool, fresh, pure drinking water to each worker;
• Shade - Provide proper shade when temperatures exceed 80 degrees and encourage workers to cool off at any time upon request.

Employers must also heed preventative measures for indoor workspaces. Heat Ahead Employee High Temperature Protections Are a Priority (May 14, 2026)

Certain industries have additional high-heat requirements, including agriculture, construction, landscaping, oil and gas extraction, and transportation of agricultural products, construction materials or other heavy materials.

Cal/OSHA’s Consultation Services Branch has a help line at 800-963-9424 for workplace health and safety questions.

Take-Aways:

Employers must take heat illness prevention obligations seriously, ensuring they provide such protections to all working in high heat conditions, outdoors and indoors.

For further information, please contact Tim Bowles, Cindy Bamforth or Helena Kobrin.

See also:

• Heat Ahead: Employee High Temperature Protections are a Priority (May 14, 2026)
• It's Hot Again: Ramp Up Heat Illness Prevention Measures (July 3, 2025)
• In the Hot Seat: Employer Pays Big for Ignoring Extreme Conditions (January 10, 2025)

Tim Bowles
September 11, 2026