California’s Division of Occupational Safety and Health has released a discussion draft proposing major amendments to its heat illness prevention standards under Assembly Bill 2243.
The proposed changes would affect both outdoor workplaces under Title 8, Section 3395 and indoor workplaces under Section 3396, significantly expanding employer obligations across the state.
The most significant proposed change is the elimination of the industry-specific exemption for high-heat procedures, which currently limits certain obligations to a narrow set of sectors.
Under existing rules, only employers in agriculture, construction, landscaping, oil and gas extraction, and certain transportation and delivery operations must comply with high-heat requirements when temperatures reach 95 degrees Fahrenheit.
The proposed rule would extend those high-heat procedure requirements to every outdoor employer in California, regardless of the industry in which they operate.
The draft also reworks the acclimatization framework, expanding the close-observation requirement beyond newly assigned workers to include employees returning after an absence of more than 14 days.
Employers would be required to choose between two compliance approaches during that 14-day observation period, giving businesses some flexibility in how they meet the new standards.
The first option involves daily pre-shift meetings covering acclimatization procedures, hydration, and emergency protocols, while the second follows a graduated exposure schedule limiting new employees to 20% heat exposure on day one, rising to 80% by day four.
Law enforcement, firefighting, and emergency response personnel would be required to use the graduated exposure approach when new or returning employees participate in high-intensity training.
An exception exists where employers can demonstrate that the employee already worked under similar heat conditions during the prior 14 days, providing a practical carve-out for experienced staff.
The draft also adds rhabdomyolysis to the list of medical conditions classified as heat illness, with signs or symptoms including muscle cramps, pain, abnormally dark urine, muscle weakness, exercise intolerance, and death.
Cal/OSHA notes that rhabdomyolysis “can be asymptomatic,” making it a particularly difficult condition for employers and workers to identify without proper awareness and training.
Employers in industries not currently subject to high-heat procedures have the most to gain from reviewing the draft closely and understanding what new compliance steps may be required.
Stakeholders wishing to submit comments on the proposed rules have until 21 September 2026 to do so via the California Department of Industrial Relations website.
Legal experts advising employers suggest that now is a practical moment to review existing heat injury and illness prevention plans and procedures, well ahead of any formal adoption.