The Arsenal Files 4/The Arsenal Files 4 (Arsenal Computer).ISO/health/osha.16

Text File | 1995-01-22 | 9KB | 163 lines

INFORMATION DATE  19920925
DESCRIPTION       USDOL Program Highlights, Protecting Workers in Hot
                  Environments
TOPIC             Hot Environments
SUBJECT           Protecting Workers in Hot Environments
ABSTRACT          Many workers spend a good part of their time in hot
                  environment. The body reacts to high external
                  temperature by circulating blood to the skin which
                  increases skin temperature and allows the body to give
                  off its excess heat through the skin. However, if the
                  muscles are being used for physical labor, less blood
                  is available to flow to the skin and release the heat.
                  Steps should be taken to reduce chances of heat stress
                  and heat disorders such as stroke, exhaustion, cramps,
                  fainting and heat rash. Information is available to
                  aid in preventing or reducing these problems.



U.S. Department of Labor
Program Highlights
_________________________________________________________________________
Fact Sheet No. OSHA 92-16

                     PROTECTING WORKERS IN HOT ENVIRONMENTS

Many workers spend some part of their working day in a hot environment.
Workers in foundries, laundries, construction projects and bakeries ■- to name
a few industries ■- often face hot conditions which pose special hazards to
safety and health.

HEAT STRESS CAUSES BODY REACTIONS

Four environmental factors affect the amount of stress a worker faces in a hot
work area: temperature, humidity, radiant heat (such as from the sun or a
furnace) and air velocity.  Perhaps most important to the level of stress an
individual faces are personal characteristics such as age, weight, fitness,
medical condition and acclimatization to the heat.

The body reacts to high external temperature by circulating blood to the skin
which increases skin temperature and allows the body to give off its excess
heat through the skin.  However, if the muscles are being used for physical
labor, less blood is available to flow to the skin and release the heat.

Sweating is another means the body uses to maintain a stable  internal body
temperature in the face of heat. However, sweating is effective only if the
humidity level is low enough to permit evaporation and if the fluids and salts
lost are adequately replaced.

Of course there are many steps a person might take to reduce the risk of heat
stress, such as moving to a cooler place, reducing the work pace or load,
removing or loosening some clothing.

If the body cannot dispose of excess heat, it will store it.  When this
happens, the body's core temperature rises and the heart rate increases.  As
the body continues to store heat, the individual begins to lose concentration
and has difficulty focusing on a task, may become irritable or sick and often
loses the desire to drink.  The next stage is most often fainting and then
possible death if the person is not removed from the heat source.

HEAT DISORDERS

Heat stroke, the most serious health problem for workers in hot environments,
is caused by the failure of the body's internal mechanism to regulate its core
temperature.  Sweating stops and the body can no longer rid itself of excess
heat. Signs include (1) mental confusion, delirium, loss of consciousness,
convulsions or coma; (2) a body temperature of 106 degrees F or higher; and (3)
hot dry skin which may be red, mottled or bluish.

Victims of heat stroke will die unless treated promptly.  While awaiting
medical help, the victim must be removed to a cool area and his or her clothing
soaked with cool water.  He or she should be fanned vigorously to increase
cooling.  Prompt first aid can prevent permanent injury to the brain and other
vital organs.

Heat exhaustion results from loss of fluid through sweating when a worker has
failed to drink enough fluids or take in enough salt or both.  The worker with
heat exhaustion still sweats but experiences extreme weakness or fatigue,
giddiness, nausea or headache.  The skin is clammy and moist, the complexion
pale or flushed, and the body temperature normal or slightly higher.  Treatment
is usually simple: the victim should rest in a cool place and drink an
electrolyte solution (a beverage used by athletes to quickly restore potassium,
calcium, and magnesium salts). Severe cases involving victims who vomit or lose
consciousness may require longer treatment under medical supervision.

Heat cramps, painful spasms of the muscles, are caused when workers drink large
quantities of water but fail to replace their bodies' salt loss.  Tired muscles
■- those used for performing the work ■- are usually the ones most susceptible
to cramps. Cramps may occur during or after working hours and may be relieved
by taking liquids by mouth or saline solutions intravenously for quicker
relief, if medically determined to be required.

   Fainting (heat syncope) may be a problem for the worker unacclimatized to a
hot environment who simply stands still in the heat.  Victims usually recover
quickly after a brief period of lying down. Moving around, rather than standing
still, will usually reduce the possibility of fainting.

   Heat rash, also known as prickly heat, may occur in hot and humid
environments where sweat is not easily removed from the surface of the skin by
evaporation.  When extensive or complicated by infection, heat rash can be so
uncomfortable that it inhibits sleep and impedes a worker's performance or even
results in temporary total disability.  It can be prevented by resting in a
cool place and allowing the skin to dry.


PREVENTING HEAT STRESS

   Most heat-related health problems can be prevented or the risk of developing
them reduced. Following a few basic precautions should lessen heat stress.

   1. Acclimatization to the heat through short exposures followed by longer
   periods of work in the hot environment can reduce heat stress.  New
   employees and workers returning from an absence of two weeks or more should
   have a 5-day period of acclimatization.  This period should begin with 50
   percent of the normal workload and time exposure the first day and gradually
   build up to 100 percent on the fifth day.

   2. A variety of engineering controls including general ventilation and spot
   cooling by local exhaust ventilation at points of high heat production may
   be helpful.  Shielding is required as protection from radiant heat sources.
   Evaporative cooling and mechanical refrigeration are other ways to reduce
   heat.  Cooling fans can also reduce heat in hot conditions.  Eliminating
   steam leaks will also help.  Equipment modifications, the use of powertools
   to reduce manual labor and using personal cooling devices or protective
   clothing are other ways to reduce the hazards of heat exposure for workers.

   3. Work practices such as providing a period of acclimatization for new
   workers and those returning from two-week absences and making plenty of
   drinking water ■- as much as a quart per worker per hour ■- available at the
   workplace can help reduce the risk of heat disorders.  Training first aid
   workers to recognize and treat heat stress disorders and making the names of
   trained staff known to all workers is essential.  Employers should also
   consider an individual worker's physical condition when determining his or
   her fitness for working in hot environments.  Older workers, obese workers
   and personnel on some types of medication are at greater risk.

   4. Alternating work and rest periods with longer rest periods in a cool area
   can help workers avoid heat stress.  If possible, heavy work should be
   scheduled during the cooler parts of the day and appropriate protective
   clothing provided.  Supervisors should be trained to detect early signs of
   heat stress and should permit workers to interrupt their work if they are
   extremely uncomfortable.

   5. Employee education is vital so that workers are aware of the need to
   replace fluids and salt lost through sweat and can recognize dehydration,
   exhaustion, fainting, heat cramps, salt deficiency, heat exhaustion, and
   heat stroke as heat disorders.  Workers should also be informed of the
   importance of daily weighing before and after work to avoid dehydration.

MORE INFORMATION

   A 15-page booklet, Working in Hot Environments, is available free from
National Institute for Occupational Safety and Health Publications, 4676
Columbia Parkway, Cincinnati, Ohio 45226; telephone [phone].
_______________________________________________________________________
This is one of a series of fact sheets highlighting U.S. Department of
Labor programs. It is intended as a general description only and does not
carry the force of legal opinion. This information will be made available
to sensory impaired individuals upon request.  Voice phone: [phone].
TDD message referral phone: [phone].