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Working Safely in Hot Environments

Most workers prefer a climate-controlled environment, but that's not always possible. Foundry workers, pastry bakers and agricultural workers are just a few of those exposed to hot or humid work environments. Hot environments can create health hazards, such as heat stroke, heat exhaustion and heat cramps. It's important to understand these heat-related illnesses and know what you can do to prevent them.

Heat Stroke

Heat stroke is the most serious problem associated with working in hot environments. It occurs when the body's ability to sweat is compromised and becomes inadequate. When the body's temperature regulatory system fails, there is little warning before victims reach the crisis stage.

According to the National Institute for Occupational Safety & Health (NIOSH), a heat stroke victim's skin is hot and usually dry, red or spotted. Body temperature is typically 105° F or higher, and the victim is generally confused and delirious. Some victims may experience convulsions or become unconscious. Death can occur if the victim does not receive quick and appropriate treatment.

Any person with symptoms of heat stroke requires immediate medical attention. The victim should be moved to a cool area, thoroughly soaked with cool water and vigorously fanned to increase cooling. Medical treatment should continue the cooling process and monitor complications that often accompany heat stroke. Early recognition and treatment of heat stroke are the only means of preventing permanent brain damage or death.

Heat Exhaustion 

Heat exhaustion is caused by the loss of large amounts of fluid by sweating, sometimes with excessive loss of sodium. A worker suffering from heat exhaustion may exhibit some of the early symptoms of heat stroke, such as fatigue, nausea or headache. In more serious cases, the victim may vomit or lose consciousness. The skin is clammy and moist, the complexion is pale or flushed and the body temperature is normal or only slightly elevated. 

In most heat exhaustion cases, the worker should rest in a cool place and drinks plenty of liquids. Victims with mild cases of heat exhaustion usually recover spontaneously with this treatment. Those with severe cases may require medical care for several days. Fortunately, there are no known long-term effects of heat exhaustion.

Heat Cramps 

Heat cramps are painful spasms of the muscles. They occur when a worker sweats profusely and drink large quantities of water but does not adequately replace the body's electrolytes. Drinking large quantities of water tends to dilute bodily fluids, while the body continues to lose sodium. The low sodium level in the muscles contributes to the onset of painful cramps. Cramps can occur in any muscle group but are most likely to develop in the muscles used most extensively. Cramps can occur during or after work hours and may be relieved by consuming salted liquids.

Preventative Measures

Many industries have attempted to reduce the hazards of heat stress with engineering controls, administrative controls and training. Engineering controls eliminate or reduce the hazard, while administrative controls and training only limit exposure to the hazard.

Engineering Controls for Hot Working Environments

Many workplace improvements can be introduced to minimize exposure to heat. For example, improving insulation on a furnace wall can reduce its surface temperature and temperature of the area around it. In a laundry room, exhaust hoods installed over the sources releasing moisture into the room will lower the humidity in the work area. In general, using fans, opening windows and creating airflow with exhaust ventilation or air blowers are simple and inexpensive ways to reduce heat and humidity. 

Administrative Controls for Hot Working Environments

There are several effective ways to limit extended periods of exposure to job-related heat, such as: 

  • Allowing workers to distribute the workload evenly throughout the day
  • Incorporating work-rest cycles 
  • Postponing nonessential tasks to cooler periods of the day 
  • Adding extra workers to help during strenuous activities 
  • Providing cool rest areas for workers  

Rest areas cooled to 76° F are generally adequate and may even feel chilly to a hot, sweating worker. Individual work periods should not be lengthened in favor of longer rest periods. Instead, workers will obtain the greatest benefit from shorter, more frequent work-rest cycles. 

A worker may lose 2-3 gallons of sweat during a workday in a hot environment. Since so many heat disorders involve excessive dehydration of the body, it is essential that water intake be about equal to the amount of sweat produced. 

NIOSH suggests drinking 5-7 ounces of water every 15-20 minutes. Drinking water should be cool, palatable and readily available to the worker. Electrolyte replacement drinks can also be used in heat-stress situations.

Employee Training

The key to preventing excessive heat stress is educating the workers on the hazards of heat and the benefits of proper controls and work practices. Employers should establish a program designed to accommodate workers who must be exposed to hot environments. Employee training should occur each year. Ideally, just before the start of the warm-weather season. An in-depth discussion should be held regarding symptoms, first aid and prevention of heat-related illnesses.

Prolonged Heat Spells

The number of heat-related illnesses typically increases during unusually hot weather conditions lasting longer than two days. This is due to progressive loss of body fluids, loss of appetite and buildup of heat in living and working areas. It is particularly important during extended hot spells to follow the preventative techniques described above. 

Double shifts and overtime should be avoided whenever possible during prolonged heat spells. Rest periods should be extended to alleviate the increase in the body heat load. The consumption of alcoholic beverages during these longer periods of heat can also cause additional dehydration and should be avoided.

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