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DLLR's Division of Labor and Industry

 

A Working Person's Guide to Prevent Heat Stress - Maryland Occupational Safety and Health (MOSH)

 

WHAT IS HEAT STRESS?

Heat stress is an illness that results from too much heat exposure. This illness may include heat exhaustion (headaches, nausea, or dizziness) or heat cramps (cramping in the muscles). If unrecognized and not treated early, heat stress can lead to heat stroke. Heat stroke can be fatal. Heat stress occurs on hot jobs.

WHAT ARE HOT JOBS?

Hot jobs have hot processes, radiant heat exposure, or unprotected sun exposure. These jobs cause constant sweating and require additional fluid intake. Workers on hot jobs must use protective measures.

WHAT ARE THE PROTECTIVE MEASURES?

1.  Take Frequent Rest Breaks
Hot jobs require rest breaks in cool areas, often on an hourly basis. With heavy work and higher temperatures, rest periods must be longer and more often on hot jobs. On hot days, employers may need to furnish relief workers.
A recommended schedule of rest breaks for your job can be provided after measurements of heat stress conditions are completed by your company or by a Maryland Occupational Safety and Health Inspector.

2.  Rest in a Cool Room
The temperature for a cool room should not be above 75 degrees Fahrenheit. This is necessary to remove the excess heat your body has built up and will not cause colds or pneumonia.

3.  Don't Wait to be Thirsty
A quart or more of water is lost each hour by sweating on hot jobs. Your body must replace this water loss by drinking water often. On very hot jobs you should drink fluid twice or more an hour. This is necessary because your stomach cannot hold enough fluid from one drink (over a quart) to adequately supply your body for one hour on a hot job.

4.  Avoid Salt Tablets
If you get heat cramps, this may indicate a need for electrolyte-containing solutions such as sports drinks. Do not use salt tablets because the average American diet has plenty of salt for a worker adjusting to a hot job. Excess salt may increase your risk for high blood pressure.

5.  Use Appropriate Clothing and Other Protection
Although it is a tradition to wear long underwear while working in hot places, this prevents the body from cooling through sweating. If hot processes give off so much heat that you feel more comfortable in long underwear, reflective clothing or other heat reflective barriers are needed. This equipment will protect you from the radiant heat and also allow cooling by sweating.

6.  Protect Your Health
Protect your health by coming to work in good physical condition. Avoid alcohol the last few hours before coming to work. If you have a hangover, your body needs more water than usual and you may be at greater risk to heat stress. If you have a hot job and are on fluid pills or other medication, check with your doctor. Although these personal measures alone are not sufficient protection, they are helpful.

These guidelines are a summary from the NIOSH Manuals for Occupational Exposure to Hot Environments, and from Principles of Industrial Hygiene, Vol. 1, 1978, by Frank A. Patty.

If you have any questions or are in need of further information and assistance regarding heat stress at your place of employment, please contact Maryland Occupational Safety and Health at (410) 527-4499.