State compliance guide · Updated April 2026

Oregon OSHA Heat Rule (OAR 437)

Short answer: Oregon OSHA enforces one of the strongest state-level heat rules in the US. Action levels at 80°F and 90°F heat index. Mandatory paid cool-down at 90°F+. Driven in part by the 2021 Pacific Northwest heat dome.

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At a glance

Oregon's heat triggers.

80°F

Initial action level

Water (32 oz/hr/worker), shade access, training, and a written Outdoor Heat Exposure Safety Program required.

90°F

High-heat trigger

Mandatory paid cool-down periods, active observation for symptoms, and stricter break schedules.

2021

Heat dome trigger

Rule strengthened after the June 2021 Pacific Northwest heat dome caused multiple worker fatalities and forced rapid policy action.

Written plan

OHESP required

Outdoor Heat Exposure Safety Program: heat illness ID, prevention, training, water/shade, cool-down, acclimatization, emergency response.

Where cooling vests fit

Built for Oregon's heat-dome reality.

Oregon's rule was forged by tragedy. Pacific Northwest summers are no longer mild. Active cooling vests extend safe productive time during 90°F+ trigger windows and reduce the frequency of mandatory stop-work breaks — without replacing them.

8–12 hrFull shift cooling between mandatory cool-downs.
90°F+Reduces core temperature buildup during high-heat windows.
No waterDoesn't compete with the 32 oz/hr hydration requirement.
PPE-fitWorn under hi-vis, FR, arc-rated outerwear.
DocumentationListed as PPE in your OHESP.

FAQ

Oregon heat rule: employer FAQ.

What is the Oregon heat rule?

Oregon OSHA's heat illness prevention rule (under OAR 437) is one of the most comprehensive state-level heat standards in the United States. It applies to outdoor and certain indoor work and triggers escalating protections based on heat index thresholds at 80°F and 90°F.

At what temperature does Oregon's heat rule apply?

Oregon's rule has two heat-index action levels. At 80°F: water (32 oz per hour per worker), shade access, training, and a written heat illness prevention plan. At 90°F: mandatory paid cool-down rest periods, observation for symptoms, and stricter break schedules.

What does Oregon's heat illness prevention plan require?

A written program covering heat illness identification, prevention measures, employee and supervisor training, water and shade provisions, paid cool-down at high-heat triggers, acclimatization for new workers, and emergency response procedures.

What industries does Oregon's heat rule cover?

Agriculture, construction, landscaping, oil and gas, utilities, transportation, and outdoor warehousing. Oregon's rule was driven in part by the 2021 Pacific Northwest heat dome that caused multiple worker fatalities.

Do cooling vests count for Oregon heat compliance?

Yes. Cooling vests are supplemental PPE under Oregon's hierarchy. They extend safe productive time during high-heat windows without replacing required water, shade, training, or cool-down periods. See our cooling vest comparison.

Oregon OSHA Heat Rule (OAR 437)

Oregon's heat triggers.

Built for Oregon's heat-dome reality.

Oregon heat rule: employer FAQ.

Keep reading.

Washington Heat Rule

Federal OSHA Heat Standard

Cooling Vest Types Compared

Build cooling vests into your Oregon OHESP.