As summer continues to keep its grip on most of the U.S., roofing contractors and workers must be increasingly vigilant to avoid health problems caused by high temperatures. Two heat-induced disorders of significant concern are heat exhaustion and heat stroke.
To keep internal temperature in a safe range, the human body rids itself of excess heat through evaporation and radiation. During evaporation, the sweat glands move water to the skin's surface to be cooled by surrounding air, reducing the internal body temperature. Heat is dissipated by radiation when the heart pumps more blood; blood vessels near the skin surface expand, bringing more blood to the surface to be cooled by surrounding air.
These mechanisms can be stressed and possibly rendered ineffective during hot, humid weather conditions. When humidity is high, sweat does not evaporate and cool the body. Similarly, if the outside temperature is high, no heat transfer occurs as the body continues to move more blood to the skin surface in an effort to cool itself.
Heat exhaustion results from the body's loss of large amounts of water and electrolytes from sweating. A worker suffering from heat exhaustion may have some or all the following symptoms: fatigue or weakness, nausea, headache, vomiting, pale or ashen face, and clammy or moist skin.
When treating a suspected heat-exhaustion case, get the worker to a cooler area. Loosen any tight or heavy clothing, and have the worker lie down. Ensuring the worker drinks plenty of cool water or sports drinks with electrolytes also is critical. Heat exhaustion quickly can develop into heat stroke, so it is important to start treatment promptly and monitor the worker continuously. Victims usually show improvement within an hour after proper treatment.
The most serious health concern related to working in a hot environment is heat stroke. Heat stroke, a life-threatening condition, results when the body's temperature-regulating system has stopped working. A worker who has heat stroke ordinarily will have an internal body temperature of 105 F (41 C) or greater. If the temperature is not brought down quickly, damage to the brain and internal organs can result. The worker also may be in a confused mental state, delirious, convulsive or unconscious. The person's skin usually will be hot, dry, and red or spotted.
A worker exhibiting symptoms of heat stroke should be hospitalized immediately, but there are some first-aid measures that also should be taken to reduce internal body temperature until medical assistance arrives. As with heat exhaustion, moving the worker to a cooler location or air-conditioned room is the first step. Because clothing can hold in heat, removing the clothing and cooling the person with wet, cool towels and directing a fan on him can be helpful. Cool liquids, such as water or sports drinks, also should be given to a worker who is conscious. The key to these steps is to reduce the internal body temperature quickly but in a controlled manner that does not cause additional harm.
The National Institute for Occupational Safety and Health (NIOSH) has some suggestions for reducing workers' exposures to heat-related hazards in the workplace. NIOSH recommends the use of work and rest cycles to allow workers' bodies to get rid of excess heat. Providing a cool area is ideal for short but frequent rest. A fan is a useful tool to assist in cooling workers in the work environment and rest area. Additionally, it is important workers get adjusted to the heat so continued exposure to heat is less stressful on the body.
According to NIOSH, it is essential water intake during the day comes close to equaling the amount the body loses through sweating. That equates to about 5 ounces to 7 ounces every 15 minutes to 20 minutes of the workday.
Make sure workers are aware of the symptoms surrounding heat-related illnesses and steps necessary to deal with heat exhaustion or heat stroke. As warmer temperatures continue, arranging work schedules to minimize worker exposure to extended periods of high temperatures; providing cool areas for rest breaks; and providing fans, adequate water or other means of heat reduction will ensure a safe, profitable summer. You can read more about the topic on NIOSH's Web site, www.cdc.gov/niosh.
Harry Dietz is NRCA's director of risk management.