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How to write a heat acclimatization plan for new and returning workers

Checked against Arizona’s published heat guidance on Oct 29, 2026 · By Anchor Point Apps · Not legal advice

Acclimatization is the part of a heat plan that most employers skip, and the one the guidance spells out most specifically.

What the guidance says

Employers should “develop and implement an acclimatization plan and procedures in writing,” choosing between:

1. Option A, the NIOSH plan. If you don’t write your own, follow the acclimatization schedule from the CDC and NIOSH. The Arizona Farm Bureau describes it as a 7-to-14-day schedule with gradually increasing exposure; check the current NIOSH document for specifics.
2. Option B, your own plan. It must account for: acclimatized vs. unacclimatized workers; the heat burden of clothing and PPE; risk factors that put workers at higher risk; and re-acclimatizing workers as necessary.

The ADOSH SEP puts it the same way: train new or returning workers on heat hazards, gradually increase workloads, ensure more frequent breaks while they acclimatize, and monitor for signs of heat illness.

What to put on paper (our suggestions)

• Who counts as “new or returning.” New hires, anyone back from extended leave or injury, and workers moving from indoor to outdoor assignments (the Arizona Farm Bureau includes this last group).
• A simple intake question, like “Where have you worked in the last two weeks?”, to decide who needs a ramp-up.
• The schedule each person is put on (for example, shorter exposure or morning shifts first), with start date and sign-off by the supervisor.
• Extra breaks and monitoring during the ramp-up, and who is watching.
• Records. One log per worker or per crew. Inspectors may ask for acclimatization records.

Our rule of thumb: pick the NIOSH option if you want the most defensible choice with the least invention, and your own plan if your work pattern really can’t follow it. Either way, the plan needs to exist in writing and be followed.

Worth knowing: ADOSH publishes a free, customizable example Heat Illness Prevention Plan and offers free, non-enforcement consultations (the Arizona Farm Bureau lists the consultation line as (602) 542-1769; confirm on the ADOSH heat page). If you’re comfortable editing a generic template, start there. A paid builder only makes sense if you’d rather answer a short set of questions and get a plan, training sign-in sheet and logs tailored to your trade and crew, in English and Spanish.

Quick answers

Not legal advice. Not a government site. Heatplan AZ is an independent project of Anchor Point Apps LLC. It is not affiliated with, endorsed by, or sponsored by the Industrial Commission of Arizona, ADOSH, OSHA, or any other government agency. Nothing here is legal or safety-engineering advice, and using a plan, checklist or guide doesn’t guarantee compliance, a clean inspection, or any outcome. Talk to a qualified safety professional or attorney about your operation.