Joe Redshaw,
Director of Social Services

With summer and hot weather approaching, it’s a good time for Local 793 operators to take steps to avoid heat stress and exhaustion. Problems caused by excessive heat can affect anyone – even the young and fit.

Construction workers are especially susceptible, though, because they’re often exposed to direct sunlight and humidity. Workers can suffer a myriad of problems from rashes and cramps to exhaustion and full-blown heat stroke. Symptoms of heat stress can include sunburn, fainting, heavy sweating, headaches and dizzy spells.

It’s important, then, for construction workers, as well as employers, to prepare ahead of time, recognize symptoms of heat stress and know how to treat it when problems arise.

Heat stress occurs when the body can no longer maintain its normal temperature. The body’s internal thermostat maintains a constant inner temperature by pumping more blood to the skin and by increasing sweat production. But in very hot environments the body temperature can rise, resulting in heat stress. When the body can no longer cope, a number of illnesses can occur, including:

Heat Rash: This is characterized by tiny red spots on the skin that can cause a prickling sensation. It’s a result of inflammation when the ducts of sweat glands become plugged.

Heat Cramps: These are sharp pains in the muscles caused by an imbalance resulting from failure to replace salt lost with sweat.

Heat Exhaustion: This is caused by loss of body water and salt through excessive sweating. Symptoms include weakness, dizziness, visual disturbances, intense thirst, headaches, vomiting, muscle cramps and diarrhea.

Heat Stroke: This condition requires immediate medical attention and is characterized by an elevated body temperature. Signs of heat stroke include dry, hot skin, a high body temperature and complete or partial loss of consciousness.

The Canadian Centre for Occupational Health and Safety also notes that prolonged exposure to heat can cause other problems such as sleep disturbances and susceptibility to minor injuries and sicknesses.

The Centre also says that the lens of the eye is particularly vulnerable to radiation produced by red-hot metallic objects because the eye has no heat sensors and lacks blood vessels to carry heat away.

The Ontario Ministry of Labour recommends that workers in a hot environment should try to drink a cup of water every 20 minutes and that workers also:

avoid working in direct sunlight;

reduce the pace of work;

increase the number of breaks;

take breaks in a cool or shaded area;

schedule heavy work for cooler periods;

wear light-coloured clothing; and

reduce the physical demands of work.

The Occupational Health and Safety Act says employers have a duty to take every precaution reasonable in the circumstances to protect workers.

This includes developing hot environment policies and procedures to protect workers in hot environments due to hot processes or hot weather.



For more information about heat exhaustion and heat stroke, go to