What do you have to do for a crew on a 100-degree day? Under federal law the answer sits in three places: the general duty clause, two construction rules that apply on every job, and OSHA's heat emphasis program, which tells inspectors where and when to look. A handful of states add a full heat rule with numbers in it. This article covers both, and ends with a plan you can run in any state.
The exposure is not rare. The Bureau of Labor Statistics found that 33.0 percent of workers were exposed to the outdoors as a regular part of their job in 2023, and at least 99.5 percent of landscaping and groundskeeping workers and of construction laborers were.
There is still no final federal heat standard
OSHA published a proposed rule, Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings, on August 30, 2024. It would require employers to create a plan to evaluate and control heat hazards in their workplace. The public hearing ended on July 2, 2025, and the post-hearing comment period closed on October 30, 2025. The latest Unified Agenda entry for the rule lists a supplemental proposal for December 2026 and final action for October 2027. Until a final rule is published, the proposal binds no one, and its dates can move.
What federal law asks of you today
The general duty clause. Section 5(a)(1) of the Occupational Safety and Health Act requires a workplace free from recognized hazards that are causing or likely to cause death or serious harm. OSHA's heat page explains how courts have read it: conditions the employer or the industry recognizes as hazardous, that cause or are likely to cause death or serious physical harm, where there is a feasible way to fix the hazard. Heat can meet that test, which is how OSHA cites heat without a heat standard.
Water and first aid. The construction sanitation standard says an adequate supply of potable water shall be provided in all places of employment, in containers that close tightly and have a tap, with no common drinking cup (29 CFR 1926.51(a)). The medical services standard, as OSHA's heat page summarizes it, requires people on site trained to give first aid when no medical facility is close by.
The penalties. For penalties assessed after January 15, 2026, OSHA's maximums are $16,550 per serious violation and $165,514 per willful or repeated violation.
The heat emphasis program
OSHA's National Emphasis Program on outdoor and indoor heat hazards, directive CPL 03-00-024, was reissued with an effective date of April 10, 2026, and runs for up to five years unless replaced. It covers general industry, construction, maritime and agriculture, and three of its rules matter to a contractor:
The directive names the key protections as water, rest, cool areas, training and acclimatization. It calls acclimatization essential: train new or returning workers on heat hazards, increase their workload gradually, give them more frequent breaks while they adjust, and watch them for signs of heat illness. It also notes that heat deaths have happened at a heat index below 80°F.
The states with their own heat rules
Where a state runs its own rule, it adds numbers the federal program does not. The main ones for outdoor trades, from each state's own text:
| State and rule | When it applies | Water | Shade, rest and observation |
|---|---|---|---|
| California, 8 CCR 3395 (outdoor); 3396 (indoor, since July 23, 2024) | All outdoor workplaces; shade above 80°F; high-heat procedures at 95°F for construction, landscaping and other listed industries; indoor rule at 82°F | At least one quart per employee per hour, free of charge | Shade big enough to sit in; preventative cool-down rest of at least 5 minutes; close observation of new employees in high heat for their first 14 days and of everyone during a heat wave |
| Washington, WAC 296-62-095 series (updated 2023) | Outdoor temperature at or above 80°F, or 52°F in nonbreathable clothing | At least one quart per employee per hour, suitably cool | Shade at all times while employees are present; at 90°F, paid cool-down rest of 10 minutes every 2 hours; at 100°F, 15 minutes every hour |
| Oregon, OAR 437‑002‑0156 (effective June 15, 2022) | Heat index at or above 80°F, indoors or outdoors | Enough for each employee to drink up to 32 ounces per hour, at no cost | Shade for outdoor workers; high-heat practices at a heat index of 90°F, including a rest break schedule (the minimum employer-designed one is 10 minutes every two hours, and 15 minutes every hour at 100°F) |
| Maryland, COMAR 09.12.32 (effective September 30, 2024) | Heat index of 80°F or higher | At least 32 ounces per employee per hour available | Shade for rest periods; acclimatization of up to 14 days for new workers and those back from 7 or more days away; a written plan; rest of 10 minutes every 2 hours above 90°F, 15 minutes every hour above 100°F |
| Nevada, regulation R131-24 (in effect since November 2024) | Businesses with more than 10 employees | Part of the written plan | A one-time job hazard analysis; where it finds heat hazards, a written plan covering water, rest when symptoms appear, cooling, monitoring, training and emergencies |
OSHA's heat page also lists Minnesota, whose standard covers indoor workplaces, and Colorado, whose heat rules are part of its agricultural labor rules. Florida went the other way: since 2024, section 448.106 of its statutes bars counties, cities and other local public bodies from requiring employers to meet heat exposure requirements beyond what state or federal law requires (their own employees aside).
A plan for the hot day, in any state
The emphasis program's sample hazard alert letter lists the controls OSHA recommends to employers it finds exposing workers to heat. Built into a day:
- Check the heat index the day before. The free OSHA-NIOSH Heat Safety Tool app shows the hourly heat index for your location; the directive lists its levels as caution below 80°F, warning from 80 to 94°F and danger at 95°F or higher. NIOSH notes that the app is not receiving updates at this time, so check the National Weather Service forecast and alerts as well.
- Put cool water close to the work and let people take frequent rest and water breaks.
- Provide shade or a cool place to rest.
- Break in new and returning workers by increasing their workload gradually.
- Schedule the hot work early, use relief workers and set work and rest periods.
- Train the crew on the signs and symptoms of heat illness, first aid and your program, and tell them that some medicines, among them diuretics, blood pressure medicines and antihistamines, can raise the risk.
- Keep an eye on each other. Washington's rule names the options: regular radio or phone contact with anyone working alone, a mandatory buddy system, or other effective observation.
A worked example. Say a landscaping company in Maryland sends a four-person crew out on a day forecast at a heat index of 101. Maryland's MOSH page says each employee should have at least 32 ounces of water available per hour, so an eight-hour day needs 4 × 32 × 8 = 1,024 ounces, which is 8 gallons, on the truck or a plan to refill it. Above 100°F, the minimum rest MOSH lists is 15 minutes every hour, so the day's schedule carries those breaks in the shade, and the new hire who started Monday is on the acclimatization plan.
Roofers face heat and height on the same day; see fall protection and the six-foot line, and for what you must record or report if someone goes to the hospital, OSHA recordkeeping and injury reporting for small crews. The roofing and landscaping pages cover pricing for those trades.
General information, not legal or tax advice. Rules change and vary by state; check with the agency named above or a professional for your situation.