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Debunking 3 Myths About Acclimatization

LHSFNA Management Co-Chairman Noel C. Borck

“As temperatures rise on construction sites across the United States and Canada, employers and Laborers should be on the lookout for heat-related illness,” says LHSFNA Management Co-Chairmen Noel C. Borck. “Heat is a serious hazard in construction. Too much heat can cause fatigue, harm job performance and increase the risk for injury.”

Tasks that require high physical exertion such as lifting heavy loads or tasks that put workers in areas with radiant heat (e.g., pouring hot asphalt) greatly increase workers’ risk for heat stress. When the body can’t cool off fast enough, the signs of heat stress soon follow: skin rash, muscle cramps and dehydration (accompanied by headaches and dizziness) are common symptoms. As heat stress worsens, it can become heat exhaustion or heat stroke, which can be fatal.

Acclimatization, the practice of allowing workers to gradually build up workloads and exposure to heat, is a critical step in preventing heat-related illnesses and fatalities. Research shows it may be the biggest factor in preventing heat-related deaths.

Acclimatization is often misunderstood or overlooked so this month we take a look at some common responses you might hear on your site and the truth behind them.

“What good is acclimatization? It’s hot today and it’ll be hot tomorrow.”

Our bodies need time to adjust to heat, especially if it’s not used to working in those temperatures. OSHA examined 20 cases of heat-related fatalities that occurred between 2012-2013 and found that nine of the deaths happened during the workers’ first three days on the job.

It usually takes about five to seven days for our bodies to acclimatize to increased heat. Gradually increasing workloads at the start of the summer, at the beginning of heat waves or for workers new to the heat are proven ways to help protect workers. Planning ahead to complete the most strenuous tasks during the coolest part of the day (e.g., in the morning) also allows jobs to stay on schedule and stay safe.

“I don’t need to worry about acclimatization if I work indoors.”

Workers are still at risk for heat stress even when indoors, especially if they are performing strenuous tasks, wearing protective clothing or are in areas with limited ventilation. Of the 20 heat-related fatalities OSHA investigated between 2012-2013, seven of them happened indoors.

Open windows and fans help dilute hot air with cooler air, allowing sweat to evaporate off the skin. Once temperatures reach 98 degrees, the use of fans is no longer recommended, as blowing hot air on the skin actually increases body temperature. Instead, make use of water, rest breaks, shade and other options.

“It doesn’t get hot enough where I live to worry about acclimatization.”

This map of heat fatalities from 2008-2014 shows that heat-related deaths happen all across the U.S. A large percentage of these fatalities occurred in states with warmer climates (e.g., California and Texas), but there were also deaths in states that are often associated with cooler climates, including Massachusetts, New York, Minnesota and Wisconsin, among others.

Heat-related fatalities between 2008 and 2014

OSHA recommends employers monitor the heat index to assess the risk to workers and implement precautions accordingly. California is the only state with a specific standard that requires employers to protect workers from heat stress. CAL-OSHA regulations require employers to establish a heat illness prevention program and train workers about the hazards of heat stress and how to prevent them. Though federal OSHA and other state programs do not have a specific heat stress standard, they have cited employers under the general duty clause for failing to protect workers from a known hazard. The LHSFNA recommends all employers take steps to protect their workers from the heat.

The LHSFNA’s Preventing Heat Stress in Construction pamphlet and Heat Stress in Construction Health Alert both provide additional information on how to protect workers from heat-related illness. For more information about creating an effective heat illness prevention program for your site, contact the LHSFNA’s Occupational Safety and Health Division at 202-628-5465.

In next month’s issue of Lifelines, we’ll take a look at how heat stress can be prevented by the lifesaving trio of water, rest and shade.

[Nick Fox]

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