There is no specific temperature that is illegal to work in under federal law. No thermometer reading automatically shuts down a jobsite. Instead, federal workplace safety law treats extreme heat and cold as hazards the employer has to control, and a small group of states have set hard temperature triggers of their own, some as low as 80°F outdoors and 82°F indoors. Whether your working conditions are actually unlawful depends on where you work, what the job demands of your body, and whether your employer is doing what safety law requires.
What Federal Law Actually Says About Temperature
The Occupational Safety and Health Act requires every employer to keep the workplace “free from recognized hazards that are causing or are likely to cause death or serious physical harm.”1Occupational Safety and Health Administration. OSH Act of 1970 – Section 5 Duties That language, known as the General Duty Clause, is how OSHA reaches dangerous heat and cold without a numeric rule on the books. Both qualify as recognized hazards when conditions are severe enough to cause serious injury.
Proving a violation takes more than pointing at a thermostat. OSHA has to show the hazard was recognized, that it could cause death or serious injury, and that a feasible way to reduce or eliminate it existed. Enforcement usually turns on whether the employer ignored obvious warning signs, like a heat advisory or a worker already showing symptoms of heat illness.
OSHA does recommend that indoor workplaces stay between 68°F and 76°F for comfort, but that recommendation carries no legal weight on its own.2Occupational Safety and Health Administration. What Can I Do if My Indoor Workplace Is Too Hot or Cold A stuffy office is not an OSHA violation. The General Duty Clause reaches conditions that put workers at real risk of heat stroke, hypothermia, cardiac events, or similar serious harm, not everyday discomfort.
What Employers Have to Do in Extreme Heat
Even without a numeric rule, the baseline expectations for hot work are well established. Employers should provide cool drinking water that workers can actually get to, shaded or air-conditioned rest areas, and frequent breaks. New workers, and employees returning after time off, need to be acclimatized — eased into hot conditions over several shifts rather than dropped into a full day of exertion. Workers should be trained to recognize the signs of heat exhaustion and heat stroke, and someone on site should know what to do when those signs appear.
These are not optional courtesies. When heat illness is foreseeable and an employer skips them, that is the fact pattern OSHA cites under the General Duty Clause. Since 2022, the agency has run a National Emphasis Program that steps up inspections on days when the National Weather Service issues a heat warning or advisory, or when the heat index is expected to reach 80°F or higher.3Occupational Safety and Health Administration. Extension of National Emphasis Program – Outdoor and Indoor Heat-Related Hazards The program has been extended through April 2026.
What Employers Have to Do in Extreme Cold
OSHA has no specific cold standard either, but the General Duty Clause applies the same way.4Occupational Safety and Health Administration. Cold Stress Guide Employers should provide warm break areas, shield workstations from wind, and supply warm liquids. A buddy system, pairing workers so they can watch each other for hypothermia and frostbite, is standard practice in cold environments. As with heat, workers should be acclimatized gradually, and the most demanding tasks should be scheduled for the warmer parts of the day when possible.
One point worth flagging: hypothermia can develop at temperatures above 40°F if a worker is wet from rain or sweat. Cold stress is not just a below-freezing problem.
States That Set a Specific Temperature
A handful of states run their own OSHA-approved safety programs and have adopted heat rules with hard temperature triggers. In those states, workers do not have to prove a General Duty Clause case — the numbers themselves create enforceable obligations.
The typical pattern is an initial trigger around 80°F outdoors that requires water, shade, and cool-down breaks. A higher threshold, usually 90°F or 100°F, brings on stronger protections such as mandatory timed rest periods, buddy systems, and emergency response plans. A few states also have indoor heat rules, with requirements starting at 82°F and additional controls at 87°F.
Not every state measures the same way. Some use the heat index, which accounts for humidity. At least one uses the Wet Bulb Globe Temperature index, which factors in air temperature, humidity, wind, and radiant heat together, and scales the permissible exposure limit to how physically demanding the work is. Under that approach, exposure limits can be as low as 77°F for strenuous labor and 86°F for light desk work.
If you work in a state with its own occupational safety agency, check that agency’s website for the exact thresholds. State standards can be stricter than federal law, but never weaker.
A Federal Heat Rule Is Proposed but Not Final
In August 2024, OSHA published a proposed rule that would set the first specific federal heat standard for outdoor and indoor work.5Federal Register. Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings It would create an initial trigger at a heat index of 80°F, requiring drinking water, rest breaks, shade or a cool-down area, and a written prevention plan, plus a high heat trigger at 90°F adding mandatory rest schedules, warning-sign monitoring, and formal acclimatization for new or returning workers.
Public comments closed in January 2025, the informal hearing concluded in July 2025, and post-hearing comments ended in October 2025.6Occupational Safety and Health Administration. Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings Rulemaking A broad executive order issued in early 2025 froze new federal rulemaking, and the heat standard was among the most prominent OSHA rules affected. As of 2026, the rule is not final and the timeline is uncertain. Until it is adopted, the General Duty Clause remains the federal tool for heat cases.
When a Medical Condition Changes the Analysis
Some medical conditions make ordinary temperatures genuinely dangerous. Multiple sclerosis, lupus, Raynaud’s disease, and certain heart conditions all fall into this category. The Americans with Disabilities Act requires employers to provide reasonable accommodations to qualified employees with disabilities, unless doing so would cause undue hardship.7U.S. Equal Employment Opportunity Commission. Enforcement Guidance on Reasonable Accommodation and Undue Hardship Under the ADA
EEOC guidance addresses temperature directly. The agency’s own example: when an air-conditioning breakdown produces unusually warm temperatures that could seriously harm an employee with multiple sclerosis, leave or a temporary work modification may be a reasonable accommodation.7U.S. Equal Employment Opportunity Commission. Enforcement Guidance on Reasonable Accommodation and Undue Hardship Under the ADA Practical accommodations often cost very little: redirecting air vents, giving the worker an enclosed space with separate climate control, shifting hours to avoid peak heat, or allowing remote work on extreme-weather days.
To use this route, tell your employer you need an accommodation for a medical condition and be ready to provide documentation. The employer then has to engage in what the EEOC calls the interactive process. They cannot simply refuse; they have to show the accommodation would create significant difficulty or expense.
When You Can Legally Refuse to Work
You can refuse to work in dangerously hot or cold conditions, but only when a narrow set of conditions all apply. This is not a general right to leave whenever you are uncomfortable. Under OSHA, all four of the following must be true:
- You have asked your employer to fix the condition and they have not.
- You genuinely believe the danger is imminent — that the conditions could kill or seriously injure you.
- A reasonable person in your position would agree the danger is real.
- The situation is too urgent to wait for a normal OSHA inspection.
When all four are met, the employer cannot lawfully fire, discipline, or demote you for refusing.8Occupational Safety and Health Administration. Workers Right to Refuse Dangerous Work A crew being told to keep working after a coworker collapses from heat stroke is the kind of scenario that clearly qualifies. A warm office with a broken air conditioner almost certainly does not.
Group refusals get an extra layer of protection. The National Labor Relations Act protects “concerted activity,” which includes group refusals to work in unsafe conditions.9National Labor Relations Board. Concerted Activity A single worker raising concerns on behalf of coworkers, or trying to organize a collective response, can also be covered. An employer that retaliates against a coordinated refusal risks both OSHA and NLRB complaints.
How to Complain Without Getting Fired
Start inside the company, and put it in writing. An email or written note to your supervisor about the conditions creates the paper trail that matters later. Document what you are seeing: temperature readings, photos, dates and times, and what protections are missing — no water, no shade, no warm break area.
If the internal route fails, you can file a confidential safety complaint with OSHA online, by phone, or at a local office.10Occupational Safety and Health Administration. File a Complaint You will need your employer’s name and address and a description of the hazard. Signed complaints from current employees are more likely to trigger an on-site inspection than anonymous tips.
Section 11(c) of the OSH Act makes it illegal for an employer to fire, demote, discipline, or threaten a worker for filing a safety complaint, participating in an OSHA inspection, or exercising any other right under the Act.11Whistleblowers.gov. Occupational Safety and Health Act, Section 11c If retaliation happens, you have 30 days from the retaliatory action to file a separate whistleblower complaint with OSHA.10Occupational Safety and Health Administration. File a Complaint That 30-day window is short, so act quickly.