Too Hot To Handle

Working in extreme high temperatures is not only uncomfortable, it can be life threatening. Many people are exposed to heat as part of their day-to-day jobs, either outdoors during summer months or in hot indoor environments. Operations involving high air temperatures, radiant heat sources, high humidity, direct physical contact with hot objects or strenuous physical activities, have the potential for causing heat-related illness.

Outdoor work where this type of risk exists includes construction, farm work, landscaping, oil and gas refining, emergency response, municipal operations, or anything else that exposes workers to direct sun and humidity. Indoor environments could include foundries, laundry operations, kitchens, mines, steam tunnels or boiler rooms and manufacturing.

It’s important for both workers and their employers to minimize the chances of heat-induced illnesses by being aware of the risks and by putting measures in-place to offset them. There is also a direct responsibility on behalf of employers to protect workers based on Occupational Health & Safety Act (OHSA) regulations.

How It Affects Your Health

Our bodies are designed to get rid of excess heat in order to maintain a stable internal temperature and optimal health. This takes place mainly through the increased circulation of blood to the skin and through sweating. When the air temperature is close to or warmer than normal body temperature, cooling of the body becomes more difficult. Sweating then becomes the primary method of cooling, but if humidity levels are high, then this too becomes an issue.

The body will store heat if it can’t get rid of it, causing the core temperature to rise and the heart rate to increase. At this stage, concentration becomes more difficult, irritability and sickness set in and the desire to drink is lost. As this process continues, fainting will typically follow and death may occur if the person is not properly cooled down and hydrated.

These heat-related health issues can be made even more serious with workers who engage in heavy work tasks or use bulky or non-breathable protective clothing and equipment.

Some workers may also be at greater risk than others if they have not built up a tolerance to hot working environments, are on certain medications or if they have other medical conditions.

Formal first aid training and facilities should be available for workplaces that deal with high heat conditions. Generally, if someone is suffering from a heat related illness, they should be moved to a cool location, should lie down and take small sips of cool fluids until they recover. PPE should be removed to allow the body temperature to lower and a spray bottle with cool water is sometimes necessary to speed the process. For more serious conditions where a worker has fainted or has vomited, has a weak pulse, extreme fatigue, pale skin, has stopped sweating or is acting irrationally, emergency medical services should be called immediately.

The most common heat-related health conditions include:

Heat rash, also known as prickly heat, is a skin irritation caused by sweat that does not evaporate from the skin. Heat rash is the most common problem in hot work environments.

Heat cramps are caused by the loss of body salts and fluid during sweating. Low salt levels in muscles can cause painful cramps. These cramps may occur during or after working hours.

Dehydration occurs when the body doesn't have enough water and other fluids to carry out its normal functions.?

Heat Exhaustion is the body’s reaction to losing excessive amounts of water and salt through sweat.??

Heat stroke is the most serious form of heat-related illness and happens when the body becomes unable to regulate its core temperature. Sweating stops and the body can no longer rid itself of excess heat. Signs include confusion, loss of consciousness, and seizures. Heat stroke is a medical emergency that may result in death. Emergency medical services (911) must be called immediately.

Planning For Hot Conditions

Employers have the responsibility of protecting workers from heat-related illness by putting formal plans and protocol in-place and maintaining them strictly. A Heat Stress Control Plan is necessary to limit exposure to potentially dangerous high temperatures in the workplace and to keep employees healthy and productive. For process heat sources (furnaces, smelters, machinery etc.), Threshold Limit Values (TLV’s) should be established jointly between your own internal health & safety committee and official occupational health & safety representatives. For weather-related heat conditions, criteria may be based on overall temperature, humidex readings, smog and other local government alerts. As a resource for specific heat tolerance levels and work times, you can reference the following website and also communicate directly with your provincial Occupational Health & Safety organization.

Once baseline standards have been set, work and production best practices can be established including:

  • Work & break time scheduling
  • Structured heat acclimation schedules
  • Availability of water, shelter & other cooling methods
  • Training
  • First aid & emergency planning
  • Personal Protective Equipment (PPE)
  • Supervision & communication
  • Working with partners

Dress For It

PPE must be worn as required by job tasks, and it’s important to factor-in the additional heat and loss of evaporation that can occur when covered-up in the heat. These items include hard hats, helmets, gloves, overalls, aprons, protective sleeves and vapour-barrier clothing. For more extreme conditions, there are higher-tech versions of PPE available that include air, water or ice cooling.

Other clothing-related rules should include:

  • Making sure that clothing worn outdoors has a tight enough weave to block out harmful UVA/UVB radiation
  • If a hard hat isn’t necessary, be sure to wear a wide brimmed hat to protect your head, face, neck and ears
  • Wear loose-fitting, light-coloured clothing that allows for adequate air flow and evaporation
  • Instead of wearing cotton (which can get soaked) close to the skin, try one of the newer fabrics that actively ‘wick’ moisture away to help keep you cool and dry
  • Wear sunglasses that offer UVA/UVB protection to avoid eye damage and strain
  • Be sure to apply sunscreen with a high SPF factor regularly if you work outdoors. Even if you tan naturally, your skin can become damaged after many hours (or years) working in direct sunlight.

Beat The Heat

Here are some other hints & tips on working effectively and safely in the heat:

  • Ensure that all workers and supervisors know the risks of working in hot conditions, can recognize the signs of illness and know how to react
  • If possible, avoid working outdoors or undertaking overly strenuous tasks when the sun is at its most intense (mid-day)
  • To help increase the chances of a successful transition to working in the heat, workers should gradually increase their workload over time to be able to acclimatize their bodies to the added stress. For example, allow workers to get used to hot environments by increasing exposure over at least a 5-day work period. Begin with 50% of the normal workload and time spent in the hot environment, and then gradually build up to 100%. New workers and those returning from an absence of two weeks or more stick to the 5-day minimum adjustment period. While a significant amount of acclimatization occurs rapidly in that first week, full acclimatization may require up to two or three weeks.
  • Engineering controls like shelters, air conditioning, added ventilation, cooling and exhaust fans, reflective shields and insulation on machinery all help to reduce risk
  • Workers must have adequate potable (safe for drinking) water close to the work area, and should drink small amounts frequently throughout the day. On average, workers should consume a ½ liter of fluid per hour in order to stay properly hydrated. Sports drinks are also a good alternative, as they help to replenish vital minerals and electrolytes as you sweat.
  • Rotating job functions among workers can help minimize overexertion and heat exposure
  • Rather than being exposed to heat for extended periods of time during the course of a job, workers should, wherever possible, be permitted to distribute the workload evenly over the day and incorporate work/rest cycles. Ideally, rest periods should be taken within lightly air-conditioned or fully shaded spaces.
  • Work in hot environments should not be conducted alone. A buddy system should be used to share workload, monitor symptoms of heat related illness and ensure adherence to the safety program (taking water breaks etc.).
  • The physical demands of work tasks in overly hot conditions can be reduced through the use of mechanical assistance (hoists, lift–tables, etc.)
  • Additional workers can be assigned to a shift or the pace of work can be slowed to help reduce heat stress

Working in hot conditions, indoors or out, can lead to a variety of health issues on the job. Knowing the risks and taking precautions goes a long way in incident prevention.

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