Heat illness on the jobsite: a supervisor's prevention checklist

Heat kills workers every summer, and nearly every one of those deaths follows the same script: a new or returning worker, no acclimatization, high exertion, and warning signs nobody acted on. Supervisors break that script. Here's the checklist.

Before the season

• Write a heat plan: triggers (heat index thresholds), work/rest schedules, hydration expectations, emergency procedures, and who has authority to stop work.
• Train the crew to recognize symptoms in themselves and each other — dizziness, headache, nausea, confusion, and critically, someone who stops sweating or becomes disoriented.
• Identify shade and cooling options for every site before crews mobilize.

Acclimatization: the one that saves lives

Most heat fatalities happen in a worker's first week — many on the first day. Ramp new and returning workers gradually: a common approach is starting near 20% of expected heat exposure and increasing over one to two weeks. "He's young and fit" is not a substitute; fitness doesn't confer acclimatization.

Every hot day

• Water positioned at the work area — not back at the trailer. Encourage a cup every 15–20 minutes; don't wait for thirst.
• Scheduled rest breaks in shade that lengthen as the heat index climbs.
• Schedule the heaviest work for the coolest hours where the job allows.
• Use a buddy system; nobody works alone in high heat.
• Watch the heat index, not the thermometer — humidity is what overwhelms the body's cooling.

When someone shows symptoms

Heat exhaustion — heavy sweating, weakness, nausea, headache: move them to shade, cool them, hydrate them, and don't send them back out that day. Heat stroke — confusion, slurred speech, collapse, hot skin with or without sweating — is a medical emergency: call 911, then cool the worker aggressively with water and ice while you wait. Minutes decide the outcome.

Why this belongs in your training program

Several states (California, Washington, Oregon, Colorado, Maryland and more) have enforceable heat standards, and federal OSHA cites heat under the General Duty Clause while its national heat rule advances. Documented heat training for supervisors and crews is both the right thing and the defensible thing — make it part of onboarding for every outdoor role.