Heat rules in Minnesota: Minnesota Rules 5205.0110, an indoor heat limit
What Minnesota Rules part 5205.0110 says about indoor heat: WBGT limits of 77, 80 and 86 degrees Fahrenheit by work type, a definition of indoor, and the training rule it points to.
Checked against the sources at the bottom of this page on October 9, 2026. Rules, fees and pay change: the source has the last word.
This page reports what the official source says. It is not legal advice: ask the office named here. It restates Minnesota Rules part 5205.0110 (Indoor ventilation and temperature in places of employment) and part 5206.0700 (Training), as published by the Office of the Revisor of Statutes, with two OSHA pages, as read on October 9, 2026. OSHA's heat standards page lists Minnesota among the states with a heat standard and says the standard applies to indoor places of employment. OSHA's State Plans page says Minnesota operates an OSHA-approved State Plan covering most private sector workers and all state and local government workers. The comparison of every place is on the heat rules overview.
What the rule says about heat
Subpart 2 of part 5205.0110 covers employee exposure to indoor environmental heat conditions. It defines the wet bulb globe temperature index (WBGT) as a measure of the combined effect of air temperature, air speed, humidity and radiation, with the formula 0.7 times the natural wet-bulb temperature plus 0.3 times the globe temperature. It sorts work by energy use: heavy work is 350 or more kilocalories an hour, moderate work is 200 to 350, and light work is up to 200. Employees are not to be exposed to indoor environmental heat conditions above the values in its Table 1, which the rule says apply to fully clothed acclimatized workers.
| Work activity | Two-hour time-weighted average WBGT limit |
|---|---|
| Heavy work | 77 degrees Fahrenheit |
| Moderate work | 80 degrees Fahrenheit |
| Light work | 86 degrees Fahrenheit |
Employees with exposure to heat are to be provided training according to part 5206.0700, subparts 1 and 3. Those subparts say training is made available by, and at the cost of, the employer; that records of it are kept three years; and that for employees routinely exposed to a harmful physical agent at or near its limit the training covers, among other items, the agent's name, the exposure level restricted by standards or professional guidelines, known acute and chronic effects, known symptoms, appropriate emergency treatment, the known proper conditions of exposure, and a written copy of that information kept readily accessible where employees may be exposed.
What "indoor" means
Subpart 5 defines "indoor" as any space between a floor and a ceiling that is bound on all sides by walls, and says a wall includes any door, window, retractable divider, garage door or other physical barrier, temporary or permanent, whether open or closed. Subpart 2 opens by saying its requirements cover exposure to indoor environmental heat conditions. The same part sets cold minimums of 60 degrees Fahrenheit for heavy work and 65 degrees Fahrenheit for light to moderate work in indoor places, unless process requirements prevent it.
The pages read name no Minnesota heat limit for outdoor work. The federal side is on the United States page.
Sources
- Office of the Revisor of Statutes, Minnesota Rules 5205.0110 Indoor ventilation and temperature in places of employment, read October 9, 2026
- Office of the Revisor of Statutes, Minnesota Rules 5206.0700 Training, read October 9, 2026
- OSHA, Heat standards in specific states, read October 9, 2026
- OSHA, State Plans, read October 9, 2026