Labor & Employment Law Daily Wrap Up, STATE REGULATIONS—CALIFORNIA—Regulators propose revisions to indoor and outdoor heat illness standards, (Aug 21, 2026)

By Patricia K. Ruiz, J.D.

The draft regulation would broaden high-heat requirements, expand medical definitions, and align provisions across workplace settings.

California workplace safety regulators have released a new discussion draft that would revise the state's indoor and outdoor heat illness prevention regulations. The proposal would expand the scope of outdoor high-heat procedures, add rhabdomyolysis to the definition of heat illness, and introduce a definition of personal risk factors for heat illness. The draft also includes multiple changes intended to align provisions in the indoor and outdoor standards while soliciting public comment through Sept. 21, 2026.

Expanded application of outdoor high-heat procedures. The draft would eliminate language in Section 3395 that currently limits mandatory high-heat procedures to specified industries. Existing text states that employers in industries not listed in Section 3395(a)(2) are not required to comply with the standard's high-heat procedures. The discussion draft removes both that exception and the accompanying list of industries subject to all provisions of the standard, including agriculture, construction, landscaping, oil and gas extraction, and certain transportation and delivery operations.

Section 3395 continues to state that the outdoor heat illness standard applies to all outdoor places of employment.

Heat illness definition revised. The proposal would amend the definition of "heat illness" in both the outdoor and indoor standards. Under the draft, heat illness would include heat cramps, heat exhaustion, rhabdomyolysis, heat syncope, and heat stroke.

The draft would add a definition of rhabdomyolysis and list associated signs and symptoms, including muscle cramps or pain, abnormally dark urine, muscle weakness, exercise intolerance, and death, while noting that the condition can be asymptomatic.

Personal risk factors added. The proposal would add a definition of "personal risk factors for heat illness" to both regulations. The proposed definition identifies factors such as an individual's age, degree of acclimatization, health, water consumption, alcohol consumption, caffeine consumption, and the use of medications, supplements, and recreational drugs that affect water retention or other physiological responses to heat.

Definitions and acclimatization provisions aligned. The proposal would establish a common definition of "closely observe" in both standards, describing effective monitoring of employees to detect early signs of heat illness and trigger a prompt response. The definition references frequent visual observation and two-way communication sufficient to identify behavioral signs such as fatigue, confusion, disorientation, irritability, and personality changes.

The draft would move the definition of "heat wave" into the definitions section of the outdoor standard. The proposed definition describes a heat wave as a day with a predicted high outdoor temperature of at least 80 degrees Fahrenheit and at least 10 degrees higher than the average high daily outdoor temperature during the preceding five days.

The proposal would revise acclimatization provisions applicable to newly assigned and returning employees under Section 3395(g). The draft would require acclimatization measures when a newly assigned employee, or an employee returning after an absence of more than 14 days, is assigned to a location where the predicted high temperature for the day will be at least 80 degrees Fahrenheit.

Cool-down and emergency-response provisions. The draft would add language to Section 3395 specifying that if an employee exhibits signs or reports symptoms of heat illness while taking a preventative cool-down rest, the employer must provide appropriate first aid or emergency response under the regulation's emergency procedures. The provision also states that a preventative cool-down rest period has the same meaning as a "recovery period" under Labor Code Section 226.7(a).

The indoor standard already contains comparable language, according to explanatory notes in the draft.

Training and prevention-plan changes. The proposal would revise training provisions in both standards to specify that effective training must be provided before employees begin work that can reasonably be anticipated to expose them to heat illness risks. The draft also states that training must be delivered in a language and at a literacy level employees understand and must include an opportunity for questions and answers.

The draft further would require employers to establish, implement, and maintain written heat illness prevention plans, distribute them to new hires and annually to employees, and make them available at worksites and to the Division upon request. The proposal includes parallel language in the indoor and outdoor standards governing plan distribution and availability.

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