CAL/OSHA: Allow Workers to Acclimate to Heat

With the weather heating up, the Department of Industrial Relations’ Division of Occupational Safety and Health (DIR/DOSH), also known as Cal/OSHA, informs employers that allowing their employees to acclimate to the heat is one of the best defenses against heat-related illnesses and fatalities.

"Our studies of heat-related illnesses and deaths indicate that acclimatization is an important factor in the prevention of heat illness," noted 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 heat and humidity. Most people adjust to the weather or acclimate within 4 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," Welsh said.

Raising awareness also is an important key in preventing heat illness, according to CAL/OSHA. California heat illness prevention standards require mandatory training for employees and supervisors. Information on acclimatization, encouraging employees to continuously drink water 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 workday early and pacing work activities for their workers. 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.

Employees who work indoors should take the same precautions as those who work outdoors in extreme heat, the agency said.

Employers with workers near sources of heat or inside buildings with limited cooling capabilities must ensure that their injury and illness prevention program is effective and in writing. Cal/OSHA studies show effective reduction of heat illness depends on written procedures, access to water, access to cooler areas, acclimatization and weather monitoring, emergency response and employee and supervisor training.

California became the first state in the nation to develop a safety and health regulation addressing heat illness in 2005. Cal/OSHA issued permanent heat illness prevention regulations to protect outdoor workers in 2006.

For more information on free heat illness workshops and training materials, visit the Cal/OSHA Web site at

TAGS: Archive Health
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