PROTECTING WORKERS FROM

THE EFFECT OF HEAT STRESS

Dr C G Acharya

Barge Doctor

Aset Marine Services Pvt Ltd Singapore

Workers who are exposed to extreme heat or work in hot environments may be at risk of heat stress. Exposure to extreme heat can result in occupational illnesses and injuries. Heat stress can result in heat stroke, heat exhaustion, heat cramps, or heat rashes. Heat can also increase the risk of injuries in workers as it may result in sweaty palms, fogged-up safety glasses, and dizziness. Burns may also occur as a result of accidental contact with hot surfaces or steam

Workers at risk of heat stress include outdoor workers and workers in hot environments such as firefighters, bakery workers, farmers, construction workers, miners, boiler room workers, factory workers, and others. Workers at greater risk of heat stress include those who are 65 years of age or older, are overweight, have heart disease or high blood pressure, or take medications that may be affected by extreme heat.

Factors that May Cause Heat-related Illness• High temperature and humidity• Low fluid consumption• Direct sun exposure (with no shade) or extreme heat• Limited air movement (no breeze or wind)• Physical exertion• Use of bulky protective clothing and equipment• Poor physical condition or ongoing health problems• Some medications• Pregnancy• Lack of previous exposure to hot workplaces• Previous heat-related illness

HEALTH PROBLEMS CAUSED BY HOT WORK ENVIRONMENTS

Heat StrokeHeat stroke is the most serious heat-related disorder. It occurs when the body becomes unable to control its temperature: the body's temperature rises rapidly, the sweating mechanism fails, and the body is unable to cool down. When heat stroke occurs, the body temperature can rise to 106 degrees Fahrenheit or higher within 10 to 15 minutes. Heat stroke can cause death or permanent disability if emergency treatment is not given.

SymptomsSymptoms of heat stroke include:•Hot, dry skin or profuse sweating•Hallucinations•Chills•Throbbing headache•High body temperature•Confusion/dizzinessSlurred speech

First Aid

Take the following steps to treat a worker with heat stroke:•Call 911 and notify their supervisor.•Move the sick worker to a cool shaded area.•Cool the worker using methods such as:

Soaking their clothes with water.Spraying, sponging, or showering them with water.Fanning their body.

Heat Exhaustion

Heat exhaustion is the body's response to an excessive loss of the water and salt, usually through excessive sweating. Workers most prone to heat exhaustion are those that are elderly, have high blood pressure, and those working in a hot environment

Symptoms

Symptoms of heat exhaustion include:•Heavy sweating•Extreme weakness or fatigue•Dizziness, confusion•Nausea•Clammy, moist skin•Pale or flushed complexion•Muscle cramps•Slightly elevated body temperature•Fast and shallow breathing

First AidTreat a worker suffering from heat exhaustion with the following:

•Have them rest in a cool, shaded or air-conditioned area.

•Have them drink plenty of water or other cool, nonalcoholic beverages.

•Have them take a cool shower, bath, or sponge bath.

Heat Syncope

Heat syncope is a fainting (syncope) episode or dizziness that usually occurs with prolonged standing or sudden rising from a sitting or lying position. Factors that may contribute to heat syncope include dehydration and lack of acclimatization.SymptomsSymptoms of heat syncope include:•Light-headedness•Dizziness• Fainting

First Aid

Workers with heat syncope should:•Sit or lie down in a cool place when they begin to feel symptoms.•Slowly drink water, clear juice, or a sports beverage.

HEALTH PROBLEMS CAUSED BY HOT WORKENVIRONMENTSHeat Cramps are muscle pains usually caused by physical labor in a hot work environment. Heat cramps are caused by the loss of body salts and fluid during sweating. Workers with heat cramps should replace fluid loss by drinking water and/or carbohydrate-electrolyte replacement liquids (e.g., sports drinks) every 15 to 20 minutes.

HEALTH PROBLEMS CAUSED BY HOT WORKENVIRONMENTS

Heat Rash is the most common problem in hot workenvironments. Heat rash is caused by sweating andlooks like a red cluster of pimples or small blisters.Heat rash usually appears on the neck, upper chest,in the groin, under the breasts and in elbow creases.The best treatment for heat rash is to provide a cooler,less humid work environment. The rash areashould be kept dry. Powder may be applied toincrease comfort. Ointments and creams should notbe used on a heat rash. Anything that makes the skin warm or moist may make the rash worse.

ENGINEERING CONTROLS TO PREVENT HEAT-RELATED HEALTH EFFECTS

The best way to prevent heat illness is to make the work environment cooler. In outdoor situations, this may be done by scheduling activities during the cooler times of the day. However, very early starting times may result in increased fatigue. Also, humidity tends to be higher in the early morning hours.Provide air conditioned or shaded areas close to the work area and allow frequent rest breaks.

ENGINEERING CONTROLS TO PREVENT

HEAT-RELATED HEALTH EFFECTIndoor workplaces may be cooled by using air conditioningor increased ventilation, assuming that cooler air is available from the outside. Other methods to reduce indoor temperature include: providing reflec-surfaces, and decreasing water vapor pressure, e.g., by sealing steam leaks and keeping floors dry. The use of fans to increase the air speed over the worker will improve heat exchange between the skin surface and the air, unless the air temperature is higher than the skin temperature. However, increasing air speeds above 300 ft. per min. may actually have a warming effect. Industrial hygiene personnel can assess thedegree of heat stress caused by the work environment and make recommendations for reducing heatexposure.

WORK PRACTICES TO PREVENT HEAT-RELATED HEALTH EFFECTS

1)Train workers and supervisors about the hazards leading to heat stress and ways to prevent them.2)Allow workers to get used to hot environments by gradually increasing exposure over a 5-day work period. Begin with 50% of the normal workload and time spent in the hot environment and thengradually build up to 100% by the fifth day. New workers and those returning from an absence of two weeks or more should have a 5-day adjustment period.3)Provide workers with plenty of cool water in convenient, visible locations close to the work area.Water should have a palatable (pleasant and odor free) taste and water temperature should be 50- 60°F if possible.

WORK PRACTICES TO PREVENT HEAT-RELATED HEALTH EFFECTS4)Remind workers to frequently drink small amounts of water before they become thirsty to maintain good hydration. Simply telling them to drink plenty of fluids is not sufficient. During moderate activity,in moderately hot conditions, at least one pint of water per hour is needed. Workers should drink about 6 ounces or a medium-sized glass-full every 15 minutes. Instruct workers that urine should beclear or lightly colored.5) Be aware that it is harmful to drink extreme amounts of water. Workers should generally not drink more than a total of 12 quarts of fluid in 24 hours.•6)Reduce the physical demands of the job, such as excesive lifting, climbing, or digging with heavy objects. Use mechanical devices or assign extra workers.

WORK PRACTICES TO PREVENT HEAT-RELATED HEALTH EFFECTS

7)Monitor weather reports daily and reschedule jobs with high heat exposure to cooler times of the day. When possible, routine maintenance and repair projects should be scheduled for the cooler seasons of the year.•8)Schedule frequent rest periods with water breaks in shaded or air-conditioned recovery areas.•9)Workers are at an increased risk of heat stress from personal protective equipment (PPE), especially from wearing semi-permeable (penetrable) or impermeable clothing (such as Tyvek or rubber),when the outside temperature exceeds 70°F, or while working at high energy levels. These types of clothing materials trap heat close to a worker’s body. Workers should be monitored by establishing a routine to periodically check them for signs and symptoms of overexposure

Recommendations for Workers•Workers should avoid exposure to extreme heat, sun exposure, and high humidity when possible. When these exposures cannot be avoided, workers should take the following steps to prevent heat stress:•Wear light-colored, loose-fitting, breathable clothing such as cotton.

Avoid non-breathing synthetic clothing.•Gradually build up to heavy work.•Schedule heavy work during the coolest parts of day.•Take more breaks in extreme heat and humidity.

Take breaks in the shade or a cool area when possible.•Drink water frequently. Drink enough water that you never become thirsty. Approximately 1 cup every 15-20 minutes.•Avoid alcohol, and drinks with large amounts of caffeine or sugar.•Be aware that protective clothing or personal protective equipment may increase the risk of heat stress.