OSHA Heat Rule and Construction: What Contractors Should Be Preparing For

Key takeaways:

• There's still no federal heat standard. OSHA's 2024 proposal is being reworked, and in mid-September its standards director said a supplemental proposal, with another public comment period, may come in the coming months. The regulatory agenda targets December 2026.
• Enforcement isn't waiting. OSHA's revised heat emphasis program took effect April 10, 2026 and runs for five years, with random heat inspections in high-risk industries, construction included, on days the National Weather Service issues a heat advisory or warning.
• Inspectors evaluate the heat program and whether workers and supervisors understand it. With contractors managing an average of 43 active jobsites in hot weather, according to AGC's 2026 Heat Safety Survey, the real work is proving the program ran on every site, every hot day.

What should construction contractors prepare for? Two things at once: a federal heat standard that isn't final and is about to change, and an enforcement program that's already running. OSHA proposed its Heat Injury and Illness Prevention standard in August 2024, held public hearings in the summer of 2025, and now expects to issue a revised proposal before finalizing anything.

Meanwhile, its revised heat emphasis program sends inspectors to construction sites on heat advisory days with a simple request: show us your heat program. For a contractor with one site, that's a binder. For a contractor running dozens of projects with changing crews and subcontractors, it's a records problem. This guide covers where the rule stands, what the proposal would require, what inspectors look for now, and what to document so the answer holds up on every site.

Where the OSHA Heat Rule Stands

OSHA published its proposed rule, Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings, in the Federal Register on August 30, 2024. It would apply to employers in general industry, construction, maritime, and agriculture wherever OSHA has jurisdiction. Public hearings ran from June 16 to July 2, 2025.

In mid-September, at the National Safety Council's Safety Congress, Andrew Levinson, director of OSHA's Directorate of Standards and Guidance, said the agency may publish a supplemental notice of proposed rulemaking in the coming months because it has "different thoughts" on parts of the 2024 proposal. The comments and evidence from the original rulemaking stay in the record, and the supplemental proposal will open another public comment period. The federal regulatory agenda targets December 2026 for the supplemental proposal and fall 2027 for a final rule. Agenda dates are targets, and they often slip.

AGC supports protecting workers from heat but has pushed OSHA for a flexible, performance-based rule in place of one framework applied across every industry. Until a standard is final, OSHA enforces heat hazards under the OSH Act's General Duty Clause.

What the 2024 Proposal Would Require

The supplemental proposal is where OSHA's changes will show up, so treat the 2024 text as the direction of travel, not the final numbers. As proposed, it would require:

• A written heat injury and illness prevention plan, with at least one designated heat safety coordinator.
• At an initial heat trigger of an 80°F heat index, or the equivalent wet bulb globe temperature: drinking water, shaded or air-conditioned break areas, rest breaks as needed, an acclimatization plan for new and returning workers, and regular two-way communication with workers.
• At a high heat trigger of a 90°F heat index: paid rest breaks of at least 15 minutes every two hours, with meal breaks allowed to count, a system for observing workers for signs of heat illness, such as a buddy system, contact at least every two hours with anyone working alone, and hazard alerts covering water, rest breaks, emergency response, and where the break areas are.
• Training for workers and supervisors, and procedures for responding to heat illness and heat emergencies.

One detail in the proposal matters more to construction than to most industries: time spent removing PPE or traveling to and from the break area doesn't count toward the rest break.

Enforcement Is Already Here: The 2026 Heat NEP

OSHA's original heat National Emphasis Program expired on April 8, 2026. Two days later, OSHA issued a revised version, and it's in effect for five years. What it does:

• Directs inspection priorities to 55 high-risk industries, using OSHA and Bureau of Labor Statistics data from 2022 to 2025. Construction industries are on the target list.
• Sends inspectors on random heat-focused inspections in those industries on days the National Weather Service issues a heat advisory or warning.
• Expands any inspection where there's evidence of heat hazards on a heat priority day, a day with a heat index of 80°F or higher.
• Drops the 2022 version's numerical inspection goal, which had asked OSHA's regional offices to double their heat enforcement activity.
• Introduces two reorganized appendices, one for evaluating an employer's heat program and one for citation guidance.

The evaluation appendix is the part to read closely. According to AGC's summary, a heat program can be written or oral, employees and supervisors have to be able to show they understand it, and a designated heat safety representative should be implementing and managing it. An oral program that nobody on site can explain is hard to defend in an inspection.

Stefano Braganti, SafetyClerk's co-founder, says the company has been told heat is a big focus for OSHA. "On the proactive inspections, they do a lot of those," he says.

What the States Are Doing

Seven states have their own occupational heat standards: California, Colorado, Maryland, Minnesota, Nevada, Oregon, and Washington. Scope and triggers vary, and several start protections at 80°F.

New Mexico is in formal rulemaking on its own heat rule, and in April 2026 Virginia enacted legislation directing its Safety and Health Codes Board to develop heat illness regulations.

Florida and Texas went the other way. Florida's HB 433, in effect since July 1, 2024, bars cities and counties from requiring private employers to provide heat protections beyond what state or federal law requires, and Texas passed a similar preemption law in 2023. Florida is a federal OSHA state, so for a Florida contractor, federal OSHA's General Duty Clause and heat NEP are the heat rules that apply.

Why Construction Is Different

On September 10, AGC released a new heat resource built on its 2026 Heat Safety Survey, and two of its numbers show how construction differs from the industries OSHA used to build its assumptions. Contractors managed an average of 43 active jobsites during hot weather, five times what OSHA assumed for employers in other industries. And a minimum 15-minute break can equal about 45 minutes of impacted work time on a jobsite, once you count climbing down from scaffolding, taking off PPE, walking to a cooling area, putting the PPE back on, and getting back to the work.

AGC uses those numbers to argue for flexibility in the final rule. For a safety director, they also describe the documentation problem. A heat program has to run, and be provable, on all 43 sites, every hot day, for every crew, including subcontractors' crews. And the crews keep changing: in AGC's 2026 Workforce Survey, 83 percent of firms report turnover among new field employees in their first 90 days, which means acclimatization is a rolling job all season.

What to Document, Site by Site

Every item below answers a question an inspector, the 2024 proposal, or both will ask.

• The program itself. The heat plan, written or documented if oral, and the heat safety representative named for each site.
• Site conditions. The heat index for the day, whether the National Weather Service had an advisory or warning out, and when the program's hot-day steps started.
• The pre-shift. On hot days, heat belongs in the pre-shift: water, shade, where the break area is, and what to do if someone gets sick, with each worker's sign-off.
• Toolbox talks. Heat illness signs and response, delivered before the season and again when conditions change, with attendance.
• Acclimatization. Who is new or returning this week, and what their exposure and supervision looked like.
• Communication during the shift. Break reminders and hazard alerts, and proof they reached every worker.
• Observations and corrective actions. A missing water cooler, a break area with no shade, a worker showing symptoms, and what was done about it, with names and times.
• Subcontractors. The same records from every sub's crews, visible to the GC.

That list is a lot of paper for 43 sites. In SafetyClerk it's the daily routine: workers get the day's pre-shift briefing by text when they check in, and they review and sign it on their phones. Toolbox talks, orientations, and pre-shift logs are recorded for each worker, and incidents and near misses feed SafetyScore, so a safety director can see which sites and crews are keeping up on a hot week.

How One Florida Contractor Proves It

A SafetyClerk client in Florida has seen OSHA's heat inspections pick up over the past several months. The company told Stefano its team has always reminded workers about heat at the start of the shift. What changed is how the reminders happen and what's left behind afterward.

The client uses SafetyClerk's toolbox talks together with a group text that reaches every worker on site at once. When the temperature climbs past the company's threshold, every worker gets a message telling them to take a break and head back to the trailer, where there's water or Gatorade for everybody. Before, the only reminder came at the start of the shift. Now it comes when the heat does, and the system keeps a record.

"Now there's an audit log," Stefano says. "We alerted every worker, twice a day, and everybody read the message. I did my part."

That's the heat program running and being documented in the same step. It's also the kind of record the 2024 proposal points toward, since it calls for regular two-way communication with workers once the heat index reaches 80°F and hazard alerts at 90°F.

A Preparation Checklist for Contractors

1. Write down the heat program you already run, or document the oral one, and name a heat safety representative for every site.
2. Decide how you'll measure heat, from on-site readings or a reliable heat index source, and what changes at 80°F, at 90°F, and on National Weather Service advisory days.
3. Put heat into the pre-shift on hot days, and get every worker's sign-off.
4. Run heat illness toolbox talks before the season and when conditions change, and keep attendance.
5. Build acclimatization into onboarding for new and returning workers, and track who's in their first week.
6. Put shade and water close to the work. Less travel time shrinks AGC's 45-minute break problem.
7. Communicate during the shift, and keep proof each message reached every worker.
8. Log observations and corrective actions the same day, with names and times.
9. Hold subcontractors to the same program and the same records, and make them visible to the GC.
10. Check the states you work in, and watch New Mexico and Virginia.
11. Watch for OSHA's supplemental proposal and comment on it. AGC's Heat Safety Resource Center tracks the rulemaking.

Frequently Asked Questions

Is there an OSHA heat standard for construction in 2026?

No. OSHA proposed a heat standard in August 2024 and now plans a supplemental proposal with another comment period. Until a standard is final, OSHA enforces heat hazards under the General Duty Clause and through its heat National Emphasis Program, which covers construction.

What is the timeline for the OSHA heat rule?

The federal regulatory agenda targets a supplemental proposal in December 2026 and a final rule in fall 2027. Those dates are targets and can move.

What does OSHA look for during a heat inspection?

Under the 2026 heat NEP, inspectors evaluate the employer's heat program: whether one exists, written or oral, whether employees and supervisors can show they understand it, and whether a designated person manages it. Inspectors also look at the practical controls, such as water, rest, shade, training, acclimatization, and emergency response.

What is a heat priority day?

A day with a heat index of 80°F or higher. Under the NEP, inspectors expand any inspection that finds evidence of heat hazards on a heat priority day. On days the National Weather Service issues a heat advisory or warning, OSHA also conducts random heat inspections in high-risk industries.

What would OSHA's proposed heat rule require at 80°F and 90°F?

At an 80°F heat index, the 2024 proposal would require drinking water, shaded or cooled break areas, rest breaks as needed, acclimatization for new and returning workers, and regular two-way communication. At 90°F, it would add paid 15-minute rest breaks every two hours, an observation system such as a buddy system, check-ins every two hours with anyone working alone, and hazard alerts. The supplemental proposal may change these requirements.

Which states have their own heat standards?

California, Colorado, Maryland, Minnesota, Nevada, Oregon, and Washington. New Mexico is in rulemaking, and Virginia enacted a 2026 law directing its board to develop heat regulations. Florida and Texas bar local governments from adding heat requirements of their own.

How should a contractor document heat safety across many jobsites?

In one system that ties each record to a site, a worker, and a time: the heat program, the day's conditions, pre-shift sign-offs, toolbox talk attendance, acclimatization, shift communications, and observations and corrective actions, for subcontractors' crews as well as your own.

See your heat program running on every jobsite, with a record for every hot day. A demo takes 30 minutes.

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