A Key to Staying Safe While Working in the Heat: Acclimatization

One of the best defenses against heat-related illnesses and fatalities is allowing employees to acclimate to the heat, says the California Division of Occupational Safety and Health, also known as Cal/OSHA. Letting workers to adjust to changes in weather by gradually increasing their exposure and physical activity likely reduces the risk of heat-related issues, the agency says. "Our studies of heat-related illnesses and deaths indicate that acclimatization is an important factor in the prevention of heat illness," says Cal/OSHA Chief Len Welsh. "It is especially critical to be vigilant with new workers, and during our first exposure to the high temperatures such as those we are currently experiencing."

The risk of dying from heat illness appears to be highest for employees who just begin working in extreme heat as the body needs to adapt gradually to exertions in the heat and humidity, the agency says. Most people adjust to the weather or acclimate within four-to-14 days of regular work levels, according to Cal/OSHA heat illness prevention data. "It is imperative to monitor your employees at all times during hot weather and allow those who are new to working in hot weather to gradually adapt to the daily routine," said Welsh. Raising awareness is also an important key in preventing heat illness. In 2005, California became the first state in the nation to develop a safety and health regulation addressing heat illness, and Cal/OSHA issued permanent heat illness prevention regulations to protect outdoor workers in 2006.

The rules require mandatory training for employees and supervisors. Information on acclimatization, encouraging employees to drink water continuously throughout the day, and taking frequent cool-down breaks or preventative recovery periods in the shade, among other actions are included in the mandatory training.

In addition to the requirements outlined in the heat illness prevention regulations, employers may consider starting the work day early and pacing work activities for their workers, the agency says. Other prevention techniques include increasing the number of water and rest breaks or preventative recovery periods on hot days and encouraging the use of a "buddy system" to monitor employees in the field.