Heat illness on the job: a practical plan for attics and rooftops before the federal rule lands

OSHA's federal heat illness rule still isn't final. As of OSHA's 2026 regulatory agenda, it sits at the proposed-rule stage, with a supplemental proposal planned for December 2026 and final action listed for October 2027, dates that tend to slip¹. That doesn't mean there's nothing to do. OSHA already enforces heat hazards under the general duty clause and a heat emphasis program that names HVAC, plumbing, electrical and roofing contractors among its targets², and five states have their own rules in force.

The practical answer for a service contractor is a heat plan built on two triggers, 80°F and 90°F heat index, written so it works under the 2024 federal proposal, the state rules and the reality of attic work. This post lays out where the rules stand, what they agree on, and a plan you can run from dispatch.

Where the federal heat rule stands

The rule has been moving for five years. Here's the timeline from OSHA's own records¹³:

1. Oct 27, 2021

   Advance notice

   OSHA asks for input on a heat standard for indoor and outdoor work.

2. Aug 30, 2024

   Proposed rule published

   Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings, 89 FR 70698, proposed as 29 CFR 1910.148.

3. Jan 14, 2025

   Comment period closes

   After an extension from December 2024.

4. Jun 16 to Jul 2, 2025

   Informal public hearing

   Testimony from employers, workers and safety groups.

5. Oct 30, 2025

   Post-hearing comments close

   OSHA's rulemaking page lists no later step.

6. Dec 2026 (target)

   Supplemental proposal

   Listed in OSHA's 2026 regulatory agenda. Expected to revise the 2024 draft.

7. Oct 2027 (target)

   Final action

   The agenda's target date. Agenda dates are plans, not commitments.

A supplemental proposal means another draft and another comment period before anything becomes final. Building your plan on the exact numbers in the 2024 draft is risky. Building it on the structure that the draft, the state rules and NIOSH's guidance all share is not.

What the 2024 proposal would require

The proposed rule would cover most employers, indoor and outdoor, with two triggers⁴:

Short exposures of 15 minutes or less in any 60-minute period would be exempt. The supplemental proposal may move any of these numbers, so treat this as the direction of travel, not the final text.

What OSHA enforces today

Without a heat standard, OSHA uses the general duty clause, which requires employers to provide a workplace free from recognized hazards likely to cause death or serious harm⁵. In April 2026 OSHA reissued its National Emphasis Program on heat for up to five years². Three details matter for trade contractors:

• You're on the list. The program's construction targets include building equipment contractors (the industry group for HVAC, plumbing and electrical contractors) and foundation, structure and building exterior contractors, which includes roofing.
• Heat priority days start at 80°F. The program defines a heat priority day as one when the heat index is expected to reach 80°F or more, with more inspection activity on those days.
• Advisories trigger site visits. On days the National Weather Service issues a heat warning or advisory, OSHA offices can add construction sites to their inspection lists.

What the state rules already require

If you work in one of these states, a heat rule already applies to you. They differ in detail but share a shape^67891011:

Colorado's heat rule covers agriculture and Minnesota's covers indoor work¹². New Mexico has proposed a rule that hasn't been adopted yet¹³. Check your own state plan before each summer; this list is growing.

Notice the agreement: an 80°F trigger for water, shade and acclimatization, and a 90°F step for scheduled rest and closer watching. A plan built on those two numbers will be close to compliant almost anywhere and easy to adjust when the federal rule settles.

Why service work is different: attics, roofs and lone techs

Heat rules are written around a heat index from the weather forecast. Service techs don't work in the forecast.

Direct sun adds heat the forecast doesn't show. The National Weather Service notes that exposure to direct sunlight can increase the heat index by up to 15°F¹⁴. A 90°F forecast heat index on a rooftop is effectively a high-heat day.

Roofs and attics are much hotter than the air. EPA reports that conventional dark roofs can reach summer peak surface temperatures of 150°F to 185°F¹⁵. The Florida Solar Energy Center notes that attic temperatures can rise far above 100°F during much of the year in the Sunbelt¹⁶. A tech changing a blower motor in an attic at 2 p.m. is working in conditions no outdoor forecast captures. In California, an attic is likely an indoor work area under the indoor rule; check with Cal/OSHA for your situation.

Techs often work alone. Crews can use a buddy system. A service tech in an attic on a solo call has nobody watching for confusion or stumbling, which are the signs that heat exhaustion is becoming heat stroke. The 2024 federal proposal would require contact with lone workers at least every two hours on high-heat days⁴; we'd make it more often in an attic.

The numbers on what happens when this goes wrong: BLS counted 48 worker deaths from exposure to environmental heat in 2024¹⁷, and in 2021 and 2022 combined, construction had 620 heat-related injury and illness cases serious enough to involve days away from work¹⁸.

Acclimatization: the step that saves the most lives

If you do one thing from this post, do this one. OSHA's guidance on new workers is blunt:

OSHA adds that over 70% of heat-related deaths happen in a worker's first week¹⁹. Bodies adapt to heat over several days. A new hire who started last Monday, or a tech back from two weeks off, hasn't adapted yet.

NIOSH's recommended schedule²⁰, which the 2024 proposal closely follows⁴, limits time in the heat for the first days:

For a service tech, "heat exposure" isn't the whole shift. It's time in attics, on roofs and in direct sun. Translate the table into dispatch rules:

1. 1

   Day 1 for a new hire

   No attic or rooftop work after 10 a.m. Indoor calls, crawlspaces in the morning, shop and truck setup. If the shift is 8 hours, no more than about 1.5 hours in the heat.

2. 2

   Days 2 and 3

   One morning attic or rooftop job, then indoor or shaded work. Pair them with a mentor; this fits naturally into the first rungs of a ride-along program.

3. 3

   Day 4

   Normal assignments in the morning; avoid the hottest afternoon jobs.

4. 4

   Day 5 onward

   Normal schedule, with the same high-heat rules as everyone else.

5. 5

   Returning techs

   Anyone back from a week or more off (vacation, illness, a cooler job site) gets the shorter returning schedule. Dispatch needs to know who that is.

The ride-along program is the natural place to build this in: a new tech's first week is already mostly watching and helping, which makes it easy to keep them out of the 3 p.m. attic.

A two-trigger heat plan for a service shop

Here's the plan, written around the two numbers the rules share. Adjust it to your state's rule where it's stricter.

Below 80°F heat index: normal operations, water on every truck, training done in spring.

At 80°F heat index (initial trigger):

• Cool water available for at least a quart per tech per hour. NIOSH recommends drinking about a cup every 15 to 20 minutes, which works out to the same amount²⁰.
• Shade or air-conditioned space available for breaks: the truck cab with the AC running counts if it's there when needed.
• Acclimatization schedule enforced for new and returning techs.
• Techs can take a cool-down break whenever they need one, without asking twice.

At 90°F heat index, or 80°F with direct sun on a roof or any attic work (high trigger):

• Paid rest break of at least 15 minutes every two hours in shade or AC.
• Check-in with every tech working alone at least every two hours, and before and after any attic job.
• Attic and rooftop work scheduled before noon where possible; afternoon attic jobs moved, split or staffed with two.
• A heat alert at the morning huddle: today's forecast, the trigger reached, the plan.

Every day in season:

• Know the signs: heavy sweating, cramps, dizziness, nausea, confusion. Confusion or collapse means call 911 and start cooling immediately.
• Name a heat safety coordinator, usually the service manager or lead dispatcher.

What the plan costs: a worked example

Owners worry that rest breaks will wreck summer capacity. Run the numbers. All inputs below are hypothetical.

Say a 10-tech shop has 30 days a year at or above the high heat trigger. Two 15-minute breaks in an 8-hour shift come to 30 minutes per tech per day (some plans add a third).

The $42.77 is a rough loaded cost for a median HVAC tech, built from BLS wages and employer cost data in our HVAC technician salary guide. At three breaks a day the figure is about $9,600. That's real money, and much of it comes back: a tech who takes a 15-minute break in the cab is less likely to make the mistakes and callbacks that come with working exhausted. And it's small next to the cost of losing a tech for the season, which we worked through in why technicians quit.

The cost that matters more is capacity on the hottest days, when no-cool calls are piling up. That's a staffing question: the heat wave staffing playbook covers on-call rotations and triage for the weeks when demand and heat peak together.

Putting it into your system

A heat plan fails when it lives in a binder. It works when it's part of how the day is dispatched and recorded. Two pieces of TradesWork help: forms and checklists can attach a short heat check to job types like attic or rooftop work, set to open on arrival, and timesheets include a built-in Rest break time code, so paid cool-down breaks are recorded rather than remembered. Neither one reads the weather for you; the trigger call is still made at the morning huddle.