Heat rules in Oregon: OAR 437-002-0156 heat illness prevention
What Oregon OSHA's rule 437-002-0156 says: it applies at a heat index of 80 degrees Fahrenheit, indoors and outdoors, with shade, water, a rest break schedule at 90 degrees, a written plan and annual training.
Checked against the sources at the bottom of this page on October 8, 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 Oregon Administrative Rule 437-002-0156, Heat Illness Prevention, from Oregon OSHA's Division 2 rules (administrative order 1-2025), and Oregon OSHA's heat illness prevention page, as read on October 8, 2026. OSHA's heat standards page notes that this division also applies to construction and forest activities. The comparison of every place is on the heat rules overview.
Scope and exemptions
The rule applies whenever an employee performs work, indoors or outdoors, where the heat index (apparent temperature) equals or exceeds 80 degrees Fahrenheit. It lists exemptions: incidental exposures of no more than 15 minutes in any sixty-minute period; heat generated by the work process, which falls under a separate rule; emergency operations directly involved in protecting life or property or restoring essential services, including utilities; and buildings whose mechanical ventilation keeps the heat index below 80. Employers whose employees do only rest or light workloads, as the rule's appendix defines them, are exempt from sections (3) to (10) while the heat index is below 90 degrees. Support activities for wildland firefighters are exempt only from section (7).
Requirements
| Topic | What the rule says |
|---|---|
| Shade at a heat index of 80 degrees and above | One or more shade areas immediately and readily available, either open to the air with at least three open sides or mechanically ventilated, big enough for employees on rest to sit fully in the shade and close to the work. Trees or vegetation used as shade must give sufficient shadow, as in forests |
| Drinking water | Cool (66 to 77 degrees) or cold (35 to 65 degrees), at no cost, enough for each employee to drink up to 32 ounces per hour |
| High-heat practices when controls do not bring the heat index below 90 degrees | Communication in a language employees understand, a buddy system or regular contact for lone workers, designated people to call emergency services, and a written rest break schedule |
| Heat illness prevention plan | In writing, available at the worksite, covering training, water, rest space, the rest break schedule and acclimatization for new employees or those back after seven or more days away |
| Training | For all employees and supervisors, annually, in a language and vocabulary readily understood |
The rule says alternative cooling measures, such as cooling vests or water-dampened cotton clothing, may replace shade only where the employer can show shade is unsafe or interferes with the work, for example in high winds, and the plan must then describe their use, care and maintenance in writing. It defines acclimatization as peaking within seven to fourteen days of regular work for at least two hours per day in the heat, for fit individuals with no underlying medical conditions.
Oregon OSHA's own pages
The agency's heat page offers a key requirements factsheet, a rest break schedule options document stating that employers must develop and implement a written rest break schedule for employees exposed to a heat index of 90 degrees Fahrenheit or more, an FAQ on plans, training and exemptions, and a factsheet on high temperatures in employer-provided housing. Most of these also exist in Spanish. OSHA's heat standards page lists Oregon among the states with their own heat rules.