On-Site Magazine

Warnings issued to construction workers as heat wave rolls through

Companies urged to add heat stress info to safety talks

July 20, 2015   By STAFF REPORT

As a heat wave rolls across Ontario, construction firms and workers are being reminded to keep an eye on employees and fellow workers for signs of heat exhaustion and heat stress.

The Infrastructure Health and Safety Association is also encouraging companies to include information about heat stress during regular site safety and toolbox talks. IHSA has plenty of information about heat exhaustion and heat stress that can be downloaded from the association’s website. It also has a single page summary flyer for firms to use.

When your body’s cooling system can’t keep up with the heat, you dehydrate and your temperature rises above 38°C. That’s when you can get heat-related illnesses such as

• heat rash (plugged sweat glands)
• heat cramps (sweating has caused salt loss)
• heat exhaustion
• heat stroke (very serious—you can die).


Heat exhaustion is when your body cannot keep blood flowing both to vital organs and to the skin for cooling. Symptoms include:

• weakness, feeling faint
• headache
• breathlessness
• nausea or vomiting
• difficulty continuing work.

If you recognize any of the above symptoms, get medical aid and cool down (move to a shaded area, loosen clothing, drink cool water). It takes 30 minutes at least to cool the body down from heat exhaustion, and if it’s not treated promptly, it can lead to heat stroke.

Heat stroke is a medical emergency. You can die from it. Your body has used up all its water and salt and cannot cool itself. Your temperature rises to dangerous levels.

Symptoms of heat stroke include:

• confusion and irrational behaviour
• convulsions
• unconsciousness
• no sweating—hot, dry skin
• high body temperature—40°C or more.

If a co-worker shows symptoms of heat stroke, you should act fast.

• Call the local emergency number or get the worker to a hospital.
• Take aggressive steps to cool the worker down (immerse in a tub of cool water or cool shower, spray with a hose, wrap in cool, wet sheets and fan rapidly).
• If the worker is unconscious, don’t give anything to drink.

Here’s how to avoid heat stress in the first place:

• Wear light, loose clothing that allows sweat to evaporate. Light-coloured garments absorb less heat from the sun.
• Drink small amounts of water (8 oz) every half hour. Don’t wait until you’re thirsty.
• Avoid coffee, tea, beer, or other drinks that make you go to the bathroom frequently.
• Avoid eating hot, heavy meals that increase your body temperature.
• Remember that your physical condition can reduce your ability to deal with the heat. Age, weight, fitness, health conditions (heart disease or high blood pressure), recent illness, or medications can all affect your ability to withstand high temperatures.

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