Key Ingredients for Safe Work in Outdoor Heat - Water, Rest, Shade


Maryland Labor Department calls on employers to promote summer safety and protect employees from heat stress

BALTIMORE, MD (June 28, 2011) – The current 10-day forecast for most of Maryland calls for temperatures over 90 degrees nearly every day. Extreme heat poses health hazards for people who work outdoors. Indoor employees, especially those who work in bakeries, pizza shops, laundry facilities and kitchens, are also at risk of heat stress. The Department of Labor's (DLLR) Maryland Occupational Safety and Health (MOSH) unit is advising employers to take appropriate precautions against heat stress and be knowledgeable about the signs of heat-associated illnesses.

“The only thing more important to Marylanders than a job that provides for their families is the comfort that their loved ones are safe at work. As temperatures rise, employers and employees – especially those working outdoors – must understand the warning signs of heat stress,” said Maryland Labor Secretary Alexander M. Sanchez. “The key ingredients for safe work in extreme heat are water, rest and shade.”

"Employers should ensure that workers are acclimatized to the level of heat in which they will be working, which may take several weeks of gradual exposure to the environmental heat and work levels associated with the job," said Ron DeJuliis, DLLR Commissioner of Labor and Industry. "Also, workers should be trained in the effects of heat and be able to recognize heat stress symptoms in themselves and fellow workers."

While high temperatures are certainly a key signal to the hazards of heat associated illnesses, other factors contribute equally to the body's response to the effects of a hot work area. These include the level of work being performed, radiant heat sources (e.g., boilers, ovens, sun light), humidity, air velocity and clothing. An individual's response to heat is also affected by age, weight, fitness, medical condition and acclimatization to the heat.

High humidity levels reduce sweat evaporation and the body's ability to rid itself of excess heat. When the body cannot rid itself of excess heat it will store it, resulting in increased core body temperature and heart rate. Increased sweating dehydrates the body and reduces essential electrolytes (often resulting in severe muscle cramps). Blood pressure tends to fall.

As the body continues to store heat, an individual may begin to lose concentration and the ability to focus on a task, may become irritable or sick, and often lose the desire to drink. Eventually, the body may lose its ability to sweat and the internal core temperature will continue to rise. This can result in heat stroke, an immediate medical emergency that may result in death if not addressed immediately.

The Maryland Department of Labor recommends these actions to prevent heat stress and heat stroke:

  • Drink cool fluids. It is recommended that a worker consume about a cup of cool water (or acceptable fluid replacement drink) every 20 minutes. Avoid alcohol and caffeinated drinks.
  • Allow and take frequent breaks, preferably in cooler areas.
  • Employers should acclimatize workers to the level of heat in which they will be working. The process may take several weeks of gradual exposure.
  • Encourage workers to follow a healthy lifestyle, with adequate diet and electrolyte balance.

Questions concerning heat stress in the workplace can be referred to the Maryland Occupational Safety and Health (MOSH) program by calling 410-527-4447. Additional Information can be located on the OSHA webpage.

The Department of Labor, Licensing and Regulation protects and empowers Marylanders by safeguarding workers, protecting consumers, providing a safety net and cultivating a thriving workforce that can meet the demands of Maryland’s dynamic economy. Follow DLLR on Twitter (@MD_DLLR) and Facebook.