California’s Division of Occupational Safety and Health (Cal/OSHA) has released a revised discussion draft proposing changes to its outdoor and indoor heat illness prevention standards. The revisions are intended to implement Assembly Bill 2243 and remain open for stakeholder comment through September 21, 2026. The proposal is not yet a final or enforceable regulation. 

Among the most significant proposed changes are expanded acclimatization requirements. Newly assigned employees and employees returning after an absence of more than 14 days would be subject to enhanced monitoring when working in specified heat conditions. For outdoor work, the requirements would apply when the predicted high temperature is at least 80 degrees Fahrenheit. Employers would be required to either conduct daily pre-shift meetings addressing acclimatization, hydration, cool-down rests, and emergency response procedures or implement a graduated exposure schedule that limits an employee’s heat exposure during the employee’s initial days of work. An exception would apply if the employer can demonstrate that the employee consistently worked under similar conditions during the preceding 14 days. 

The proposal would also revise employer obligations concerning heat illness prevention plans. Employers would be required to distribute the written plan to new employees upon hire, during heat illness prevention training, and annually thereafter. As an alternative to distributing physical copies, an employer could post the plan online in English if it is presented in a format that can be easily translated into other languages. Training would continue to be required in a language and at a literacy level employees understand, with an opportunity for questions and answers. 

The outdoor standard would retain the requirement that agricultural employees take a minimum 10-minute net preventative cool-down rest period every two hours when temperatures reach 95 degrees Fahrenheit or higher. The draft would also remove the existing industry-specific limitation on high-heat procedures, extending those requirements to outdoor employers across industries. In addition, Cal/OSHA could require an employer to use wearable technology to monitor physiological responses to heat stress through an Order to Take Special Action. An employer subject to such an order would be responsible for securing the resulting health data and ensuring that it is not used to discriminate against employees. 

Although the proposed revisions remain under consideration, employers should consider taking the following steps: 

• Review current heat illness prevention plans, acclimatization procedures, training materials, and return-to-work practices. 

• Evaluate procedures for identifying and monitoring employees returning from extended absences. 

• Determine whether existing practices could support either of the proposed acclimatization options. 

Comments on the discussion draft must be submitted to Cal/OSHA at [email protected] by September 21, 2026.