The summer months bring increased risk for heat stress, which can be dangerous — and deadly. Employers should consider adopting a heat stress control program for any hot environment where workers could be at risk.
Whether you work in a hot smelting plant or outdoors in the summer months, heat exposure can be dangerous.
Workers who are exposed to extreme heat or work in hot environments may be at increased risk of heat stress.
In foundries, steel mills, bakeries, smelters, glass factories and furnaces, extremely hot or molten material is the main source of heat.
For people working outdoors in jobs such as construction, road repair, open-pit mining and agriculture, summer sunshine provides a hot environment.
In laundries, restaurant kitchens and canneries, high humidity adds to the heat burden.
In all cases, the cause of heat stress is working in an environment which can potentially overwhelm your body’s ability to deal with heat.
“Heat stress” is a buildup of body heat generated from a combination of the effort you exert while working, the environment (air temperature, humidity, air movement, radiation from the sun, or hot surfaces/sources), and the clothing and equipment you wear.
Most people feel comfortable when the air temperature is between 20 degrees Celsius and 27 degrees Celsius and when relative humidity ranges from 35 to 60 per cent.
When air temperature or humidity is higher, you may feel uncomfortable but your body can cope with a little extra heat. However, hot environments can increase your internal body temperature several degrees above the normal temperature of 37 degrees Celsius, overwhelming your body’s natural cooling systems and leading to a variety of serious and possibly fatal conditions.
ILLNESSES CAUSED BY HEAT EXPOSURE
The risk of heat-related illness is different for each person. You are at greater risk of heat stress if you have pre-existing health issues, such as excess weight, heart disease, high blood pressure, or respiratory disease, or if you are 65 years of age or older, or you take medications that may be affected by extreme heat.
Also, you may be more susceptible to heat stress if you have skin diseases or rashes.
Heat stress puts workers at risk for illnesses such as heat cramps, heat syncope, heat exhaustion, and heat stroke.
Heat can also lead to accidents resulting from sweaty palms and from accidental contact with hot surfaces.
As a worker moves from a cold to a hot environment, fogging of eye glasses can briefly obscure vision, presenting a safety hazard.
Heat cramps are sharp pains in the muscles that occur when there is a salt imbalance in your body from not replacing salt lost with sweat.
Cramps occur most often when you drink large amounts of water without enough salt (electrolyte) replacement.
You may experience heat cramps alone or combined with one of the other heat stress illnesses. Heat syncope occurs when you feel dizzy, light headed or you faint suddenly and lose consciousness due to low blood pressure.
It can be caused by blood pooling in the legs if you have been standing still for a long time in a hot environment, or by the loss of body fluids through sweating.
Your risk of developing heat syncope increases when you have not adjusted to a hot environment or are dehydrated. Resting in a cool area usually brings about a quick recovery.
Heat exhaustion is caused when you lose body water and salt through excessive sweating.
SIGNS AND SYMPTOMS
The signs and symptoms of heat exhaustion include heavy sweating, weakness, dizziness, visual disturbances, intense thirst, nausea, headache, vomiting, diarrhea, muscle cramps, breathlessness, palpitations, tingling and numbness of the hands and feet.
People usually recover after resting in a cool area and drinking cool, salted drinks like sports drinks.
Heat stroke and hyperpyrexia — elevated body temperature — are the most serious types of heat illnesses and require immediate first aid and medical attention.
Signs of heat stroke include body temperature of more than 41 degrees Celsius, and complete or partial loss of consciousness.
The signs of heat hyperpyrexia are similar to heat stroke except that your skin remains moist. Sweating is not a reliable symptom of heat stress because there are two types of heat stroke — “classical” heat stroke where there is little or no sweating (usually occurs in children, the chronically ill, and the elderly), and “exertional” heat stroke where body temperature rises because of strenuous exercise or work, and you do sweat.
Heat stroke can cause death or permanent disability if emergency treatment is delayed or not given.
PREVENTION TIPS FOR EMPLOYERS
Every year, Canadian workers die on the job because of heat-related causes. As an employer you must manage this risk by evaluating the situation and determining appropriate controls.
Depending on the workplace, a heat stress control program may be necessary.
You can help reduce the risk by managing work activities so they match the employee’s physical condition and the temperature.
Take time to train your workers on the serious health risks of heat illness, how to avoid it, how to recognize the symptoms and what to do if it happens.
Keep workers cool and hydrated. Demonstrate your commitment to worker health by allowing some flexibility in work arrangements during hot conditions.
If possible, schedule heavy tasks and work that requires personal protective equipment for cooler times, such as early mornings or evenings.
Keep the work area cool, or provide air-conditioned rest areas. For workers on duty in the heat, provide plenty of water and encourage them to drink even if they don’t feel thirsty, and to take frequent rest breaks.
PREVENTION TIPS FOR WORKERS
It can take up to two weeks to build up a tolerance (acclimate) to working in hot conditions. Stay hydrated. This is essential. As a general guideline, drink one cup of water every 15 to 20 minutes, whether you are thirsty or not.
Adapt your work and pace to the temperature and how you feel.
A simple but potentially life-saving practice is taking a break to cool off in the shade or in an air-conditioned building or vehicle. If you don’t have a shady or cool place, reduce your physical efforts.
Wear lightweight clothing and a hat.
The risk of heat illness can be greater if you wear certain types of personal protective equipment. If necessary, consider also wearing a cooling vest to help keep your body temperature down.
Avoid alcohol and drugs. They can worsen the effects of heat illness. If you are on medication, read the label or talk to your doctor to understand how it might cause your body to react to the sun and heat.
Recognize the symptoms of heat stress in yourself and your co-workers.
These symptoms include rash, cramping, fainting, excessive sweating, headache and dizziness. You may not see or feel the effects so always use the buddy system to monitor one another.
More information about heat stress and working in extreme temperatures can be found by visiting www.ccohs.ca.
The Canadian Centre for Occupational Health and Safety (CCOHS) is Canada’s national resource for the advancement of workplace health and safety. CCOHS promotes the total well-being — physical, psychosocial and mental health — of working Canadians by providing information, training, education and management systems and solutions that support health and safety programs and the prevention of injury and illness.