Heat Stress

• Primary Trigger: Prolonged exposure to temperatures over 80°F accompanied by continuous physical movement or work.
• Aggravating Factors: High rate of exertion, high humidity, low airflow, radiant heat sources, dehydration, use of alcohol/caffeine/certain medications, and wearing non-breathable clothing or heavy PPE.

1. Heat Exhaustion: Pale skin, muscle cramps, headache, dizziness, weakness/fatigue, hyperventilation, elevated heart rate, elevated body temperature (101°F–104°F), nausea, and vomiting.
2. Heat Stroke: Red/dry skin, excessive sweating or complete inability to sweat, body temperature above 104°F, confusion, slurred speech, aggression, agitation, hallucinations, seizures, or fainting.
   CRITICAL EMERGENCY: Call 911 immediately if heat stroke is suspected.

1. Buddy System: Use a buddy system or check in frequently with a supervisor. Watch yourself and co-workers for heat illness symptoms.
2. Hydration: Drink plenty of water. Each employee must have access to 32 oz. of clean water per shift (up to 4 cups per hour).
3. Cool-Down Breaks: Take small breaks in open-air shade or air-conditioned areas if feeling overheated. UW employees are encouraged to take preventative cool-down breaks.
4. Report Symptoms: Report any heat illness symptoms to a supervisor immediately and begin cooling procedures.

1. Pre-Shift Meetings: Participate in mandatory pre-shift safety briefings covering heat illness prevention, hydration, and cool-down breaks.
2. Mandatory Cool-Down Breaks:
   • At 90°F+: Take a mandatory 10-minute cool-down break every two hours.
   • At 100°F+: Take a mandatory 10-minute cool-down break at least every hour.

Acclimatization is the process of gradually adapting the human body to work in hot environments over 7 to 14 days.

• New Workers: Limit initial exposure to a maximum of 20% of a full shift in heat on Day 1, increasing exposure by no more than 20% each subsequent day.
• Experienced Workers: May work up to 50% exposure on Day 1, 60% on Day 2, 80% on Day 3, and 100% on Day 4.
• Medical Adjustments: The acclimatization period should be extended for workers with relevant medical conditions.

• New employees must be closely observed by a buddy or supervisor for their first 14 days of employment.
• Previously exposed employees must be observed using the buddy system whenever temperatures exceed 80°F.

Reach out to Environment, Health & Safety (EHS) or Environmental & Occupational Health (EOH):

• EHS Front Office: (608) 265-5000
• EOH Phone: (608) 890-1992
• Email: eoh@fpm.wisc.edu