Seyfarth Synopsis: On May 7, 2025, Cal/OSHA released a draft proposal to revise the outdoor and indoor heat illness prevention regulations (8 CCR Sections 3395 and 3396), aiming to implement requirements from AB 2243, signed by Governor Newsom at the conclusion of the 2021-22 legislative session. These proposed changes alter how employers must respond to heat hazards, and introduce new requirements for acclimatization, training, and plan distribution. Public comments are due by July 7, 2025.
Background
Signed into law in 2022, Assembly Bill 2243 directed Cal/OSHA to strengthen protections for outdoor workers exposed to heat and wildfire smoke. AB 2243 originally proposed an "ultrahigh heat" standard but was ultimately revised to focus on two main objectives for outdoor heat:
- Requiring Cal/OSHA to consider updates related to acclimatization and the distribution of Heat Illness Prevention Plans (HIPPs).
- Updating wildfire smoke protections for farmworkers, particularly the AQI threshold for mandatory respiratory protection. Cal/OSHA has yet to propose draft changes addressing this.
The proposed rulemaking released on May 7, 2025, reflects Cal/OSHA's efforts to fulfill—and exceed—the bill's first mandate: updating heat illness prevention standards. Notably, the proposed rulemaking includes changes to both outdoorandindoor requirements (T8 CCR §§ 3395 & 3396, respectively), even though AB 2234 only directed Cal/OSHA to update the outdoor requirements found in §3395.
Key Proposed Changes
Distribution of the HIPP – indoor and outdoor
Employers would be required to distribute their HIPP upon hire, during heat illness prevention training, and at least once a year to every covered employee. However, the draft language limits required distribution to no more than twice annually per employee.
Acclimatization – outdoor
Current regulations require close observation of employees newly assigned to a "high heat area." The proposed rule updates that language to specify "high heat area" to mean any area where the temperature equals or exceeds 95°F, aligning it with the existing "high heat" threshold in subsection (e).
The proposal also introduces new acclimatization requirements for employees assigned to areas with temperatures of 80°F or higher. Employers would be required to either:
- Implement high-heat procedures found in §3395(e) for five days, or
- Adopt a phased acclimatization schedule for new employees,
modeled after
Fed-OSHA's proposed heat rule:
- Day 1: 20% exposure
- Day 2: 40%
- Day 3: 60%
- Day 4: 80%
- Day 5: 100%
- For current employees returning after a break of more than 14
days, acclimatization would be limited to:
- Day 1: 50%
- Day 2: 60%
- Day 3: 80%
This phased requirement would not apply if the employer can demonstrate that the employee had consistently worked under similar heat conditions within the past 14 days.
Acclimatization – indoor
For indoor environments, employers would have two options for new or returning employees in a work area where: (A) the temperature or heat index, whichever is greater, equals or exceeds 87 degrees Fahrenheit, (B) the temperature equals or exceeds 82 degrees Fahrenheit for employees who wear clothing that restricts heat removal, or (C) the temperature equals or exceeds 82 degrees Fahrenheit:
- Apply the "assessment and control measures" section of the indoor heat standard found in §3396(e)(2) (excluding engineering controls found in §3396(e)(2)(A)) for five days, or
- Follow the same phased acclimatization schedules described above.
The same exception applies indoors as outdoors: employers can opt out of acclimatization if the employee consistently worked under comparable heat conditions during the prior 14 days.
What's Next?
Comments on the draft proposal are due by July 7, 2025, and can be submitted to:
- eberg@dir.ca.gov
- jlandaverde@dir.ca.gov
An advisory committee meeting will be scheduled by Cal/OSHA at a later date. AB 2243 requires the Cal/OSHA standards board to "consider" adopting revised rules by December 31, 2025, but does not contain a deadline for the Board to adopt the rules.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
