Heat & Cold Stress JSA

Temperature is the hazard crews most often write off as "conditions". It kills anyway — and it kills new workers disproportionately, because acclimatization takes days a first-week labourer has not had. Heat illness also progresses: the person who stops sweating and gets confused is already past the point where water and shade are enough.

There is no federal OSHA standard for heat or cold, and this page does not pretend otherwise. OSHA enforces these hazards under the General Duty Clause — Section 5(a)(1) of the OSH Act — using NIOSH criteria and the heat index as reference points. That puts more weight on the JSA, not less: with no standard to copy, your own analysis is the document that shows the hazard was recognized and controlled.

Two things are worth knowing about where the rules stand as of October 2026. OSHA's national emphasis program on heat was renewed on 10 April 2026 as CPL 03-00-024, so heat-exposed workplaces are actively targeted for inspection even without a standard. And the heat injury rule proposed in August 2024 is still not final — the Department of Labor plans a supplemental proposal in December 2026 with a target of a final rule in October 2027 — so the thresholds discussed in that proposal are not requirements today. Several states have gone ahead on their own: California, Colorado, Maryland, Oregon and Washington are among those with their own heat rules, and where one of those applies it sets real obligations that this page does not replace.

What the work involves

• Outdoor or enclosed work in high heat and humidity
• Work in cold, wind chill, rain or on snow and ice
• Heavy exertion or PPE that limits the body's cooling
• Acclimatizing new and returning workers
• Recognizing and responding to heat and cold illness

Hazards and controls

Controls are listed in hierarchy order — the further down the list a control sits, the less it should be carrying on its own.

1. Heat exhaustion progressing to heat stroke

• Eliminate/substitute: reschedule heavy work to the cooler hours; mechanize the heaviest tasks.
• Engineering: shade or air-conditioned rest areas at the work face; cool drinking water within easy reach, not a walk away; cooling vests or misting where practical.
• Administrative: work/rest cycles that shorten as the heat index rises; acclimatization over the first week for new and returning workers; buddy checks for symptoms; a response plan that includes cooling first and calling 911 for any confusion or collapse.
• PPE: light, breathable clothing — and recognition that required PPE itself adds heat load.

OSH Act Section 5(a)(1) the General Duty Clause, is how OSHA enforces heat illness hazards, because no federal heat standard exists — the duty is to keep the workplace free of a recognized hazard. OSHA CPL 03-00-024 the national emphasis program on outdoor and indoor heat hazards, renewed 10 April 2026, directs inspection activity at heat-exposed workplaces; it is an enforcement program, not a standard, and creates no new duty of its own. State heat standards California, Colorado, Maryland, Oregon and Washington are among the states that have adopted their own heat rules, which do set specific obligations wherever they apply. 29 CFR 1926.51(a) requires an adequate supply of potable drinking water to be provided in all places of employment.

2. New or returning workers unacclimatized

• Administrative: a graded acclimatization schedule — shorter exposure building up over the first week — for anyone new, returning from leave, or after a cool spell.
• Administrative: pair new workers with experienced ones who watch for symptoms, and say explicitly that stopping is allowed.
• Administrative: extra monitoring during the first heat wave of the season, which catches whole crews.

OSH Act Section 5(a)(1) is the duty under which OSHA has cited employers for failing to acclimatize new workers to heat — acclimatization is a recognized control, not a regulatory threshold.

3. Hypothermia, frostbite and cold-impaired dexterity

• Eliminate/substitute: move the work indoors or into a heated enclosure; reschedule out of the worst of it.
• Engineering: windbreaks and heated shelters; heated cabs; insulated tool handles so bare hands are not needed.
• Administrative: warm-up breaks scheduled by wind chill, not by feel; dry spare clothing available, since wet clothing is what turns cold into hypothermia; buddy system for recognizing slurred speech and clumsiness.
• PPE: layered clothing, insulated gloves and boots rated for the conditions.

OSH Act Section 5(a)(1) is how OSHA addresses cold stress, which also has no dedicated standard and no proposed rule.

4. Secondary hazards created by the weather itself

• Engineering: grit, clear or close icy walkways and scaffolds; cover and heat-trace what must stay workable.
• Administrative: stop criteria for ice on steel, scaffolds and ladders; re-inspect fall protection anchorages and ground conditions after freeze-thaw or heavy rain.
• Administrative: recognize that heat fatigue causes the errors — a tired crew on a hot roof is a fall risk, which is why this page links to the height pages.

29 CFR 1926.25(a) requires work areas and passageways to be kept clear of debris and scrap, which is the housekeeping duty that extends to keeping walkways usable.

5. Illness not recognized, or help called too late

• Administrative: train the crew and supervisors on the symptoms of both heat and cold illness, and on the fact that the sufferer is often the last to notice.
• Administrative: a written emergency response plan — who cools or warms the person, who calls, how the ambulance reaches the work face.
• Engineering: first aid provision and a trained first aider where no infirmary or clinic is near the site.

29 CFR 1926.50(c) requires a person trained in first aid to be available at the work site where no infirmary, clinic, hospital or physician is reasonably accessible.

A worked example row

This is how one line of the finished JSA reads, with the risk bands scored on the same 4-band matrix the generator prints:

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