645 Heat Injury and Illness Prevention: Employee

Oregon Requirements

Application & Scope

This section supplements OSHAcademy Course 645: Heat Injury and Illness Prevention (Employee) and is designed to align with Oregon OSHA's permanent heat illness prevention rules:

• OAR 437-002-0156 – Heat Illness Prevention (General Industry)
• OAR 437-004-1131 – Heat Illness Prevention (Agriculture)

Adopted May 9, 2022, these rules apply to any workplace where extreme heat caused by weather can expose employees to heat-related illness.

Who Must Comply

All Oregon employers whose employees may be exposed to outdoor or indoor ambient heat at or above the 80°F heat index threshold.

Exemptions

• Full Exemptions:
  • Incidental heat exposures of short duration (15 minutes or less per hour)
  • Heat generated solely by the work process (not weather), in which case measures shall be taken to control the conditions or to control the effect on the employee.
  • Emergency operations (e.g., firefighting, rescue)
  • Indoor spaces with mechanical ventilation maintaining a heat index < 80°F
• Partial Exemptions:
  • Employees performing "rest" or "light" workloads below 90°F
  • Support roles for wildland firefighters
  • Home-based employees

Access to Shade

Employers must establish one or more shade areas whenever the heat index is ≥ 80°F:

• Shade may be natural or artificial, must be open to the air or mechanically ventilated, and free of unsafe conditions.
• Must be as close as practical to work areas.
• Must be large enough to accommodate all employees on rest, recovery, or meal breaks.
• If shade access is infeasible (e.g., during high winds or travel across rangeland), employers must identify equivalent cooling measures (e.g., cooling vests with fans or ice packs, water-dampened cotton clothing, or similar effective measures).

Drinking Water

Employers must ensure:

• Cool or cold potable water (35°F–77°F) is available
• Quantity sufficient for each employee to consume 32 ounces per hour
• Water may be replenished during shifts, not necessarily all supplied at the start
• Electrolyte beverages (without caffeine), such as sports drinks, are allowed but may not fully replace the water requirement

Employees performing "rest" (e.g., sitting, thinking) or "light" (e.g., writing, driving a car, standing watch) workloads below 90°F are exempt from these specific quantities but must still have water under general Oregon OSHA provisions.

High Heat Practices

When the heat index exceeds 90°F, employers must implement these additional protections:

• Effective communication (voice, radio, or electronic) between employees and supervisors.
• Monitoring for heat illness via:
  • Regular check-ins with employees working alone
  • A mandatory buddy system
  • Another equally effective method
• Emergency medical readiness:
  • Designate employees authorized to call EMS
  • Ensure alternates can call EMS if the primary person is unavailable
• When employees work in buildings without mechanical ventilation, employers must determine the indoor heat index by using one of the following methods:
  • Directly measure the temperature and humidity in the occupied area at the same time and location
  • Use the NIOSH Heat Safety Tool app to determine the outdoor heat index and assume it is the same indoors
  • If the structure is affected by outdoor humidity (e.g., hoop houses or greenhouses), measure and use the actual indoor humidity.
• Preventive cool-down rest breaks:
  • Must occur based on one of three employer-selected options in the rule:
    • Employer-specific schedule based on the minimum durations and intervals in Table 1 and incorporate the following factors, which may require more frequent breaks:
      • How personal protective equipment (PPE) affects heat retention
      • How work clothing affects heat retention
      • Relative humidity and whether the work is indoors or outdoors
      • The intensity of the work performed
      • The effects of direct sunlight
    • NIOSH work/rest schedule:
      • Employers may use a written rest-break schedule based on NIOSH recommendations provided in Appendix A, Section 3.
    • Simplified rest break schedule:
      • Employers may use a written simplified rest-break schedule based on Table 2.
  • Breaks may coincide with other required rest or meal periods.
  • Preventive cool-down is considered paid work time

Emergency Medical Plan

The employer's Emergency Medical Plan must address employee exposure to excessive heat and comply with all applicable regulations:

When the heat index ≥ 80°F, employers must implement an emergency medical plan consistent with OAR 437-002-0161 (Medical and First Aid) or OAR 437-004-1305(4) (Agriculture). The plan must cover:

• General Industry:
  • Must meet the requirements of OAR 437-002-0161(4), which mandates procedures for obtaining emergency medical assistance and ensuring prompt medical care.
• Construction Activities (29 CFR 1926.50):
  • Availability of medical personnel
  • First-aid supplies
  • Emergency transportation
  • Communication systems for contacting emergency services
• Forest Activities (OAR 437-007-0220):
  • First-aid and emergency response procedures specific to forestry operations
  • Worker access to emergency medical services
  • Adequate training and supplies
• Never leave a symptomatic employee alone or send them home without offering first aid or medical evaluation

Acclimatization Plan

Employers must develop and implement a written acclimatization plan and choose one of the following options:

• Employer-Designed Acclimatization Plan must include:
  • Acclimated vs. unacclimated workers and their differing heat tolerances
  • Clothing and PPE that increase heat stress
  • Personal and environmental risk factors that raise the likelihood of heat-related illness
  • Re-acclimatization procedures when:
    • Weather conditions change significantly
    • A worker has been away from the job for more than seven days
  • Use and maintenance of auxiliary cooling systems, such as:
    • Water-cooled or air-cooled garments
    • Cooling vests
    • Wetted overgarments
• NIOSH Acclimatization Plan:
  • Employers who do not develop their own plan must follow the CDC/NIOSH acclimatization guidelines provided in Appendix A, Section 4.

Notes:

• There is no universal acclimatization plan due to Oregon’s variable weather
• Unfit workers require more time to acclimate than physically fit workers
• Employers should consider direct sunlight when developing their plan

Heat Illness Prevention Plan

Employers must develop, implement, and maintain a written heat illness prevention plan. The plan must be available at the worksite for employees and provided to Oregon OSHA upon request. The plan must include at least the following:

• Procedures for training employees on heat hazards and prevention methods
• How to recognize dehydration and heat-illness symptoms, and how to respond when others show signs of illness
• How cool, potable water will be supplied in adequate quantities
• How employees will be encouraged and given frequent opportunities to drink water
• How shaded or climate-controlled areas will be provided for rest, cooling, and recovery when symptoms appear
• How the employer will implement the required heat-illness prevention rest-break schedule
• How acclimatization procedures will be applied for new employees or those returning after seven or more days away

Supervisor and Employee Annual Training

All employees (including supervisors) must be trained annually in a language they understand, before work begins at sites where the heat index ≥ 80°F

Training must include:

• Environmental and personal risk factors
• Employer and employee responsibilities (water, shade, cool-down, reporting)
• Importance of frequent small water intake (up to 32 oz/hr)
• The concept, importance, and methods of the acclimatization plan implemented by the employer
• The types of heat illness, common signs and symptoms, and the appropriate first aid and emergency response—emphasizing that mild symptoms can quickly progress to serious, life-threatening conditions
• The importance of employees immediately reporting any signs or symptoms of heat illness—whether in themselves or coworkers—directly to the employer or a supervisor
• How nonoccupational factors—such as drugs, alcohol, and obesity—can reduce a worker's tolerance to heat stress.

Employers must keep written or electronic records of training. Records must include each trained employee's name or ID, the training date(s), and the trainer's name. The most recent annual training record for each affected employee must be maintained and provided to Oregon OSHA upon request.

Those performing "rest" or "light" work are exempt from annual training when the heat index is below 90°F.

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