occupational heat stress
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Occupational heat stress is the net load to which a
worker The working class (or labouring class) comprises those engaged in manual labour, manual-labour occupations or industrial work, who are remunerated via wage, waged or salary, salaried contracts. Working-class occupations (see also "Designation ...
is exposed from the combined contributions of metabolic heat,
environmental factor An environmental factor, ecological factor or eco factor is any factor, abiotic or biotic, that influences living organisms. Abiotic factors include ambient temperature, amount of sunlight, and pH of the water soil in which an organism lives. Bi ...
s, and
clothing Clothing (also known as clothes, apparel, and attire) are items worn on the body. Typically, clothing is made of fabrics or textiles, but over time it has included garments made from animal skin and other thin sheets of materials and natural ...
worn which results in an increase in heat storage in the body. Heat stress can result in heat-related
illness A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that ar ...
es, such as
heat stroke Heat stroke or heatstroke, also known as sun stroke, is a severe heat illness that results in a body temperature greater than , along with red skin, headache, dizziness, and confusion. Sweating is generally present in exertional heatstroke, ...
,
hyperthermia Hyperthermia, also known simply as overheating, is a condition in which an individual's body temperature is elevated beyond normal due to failed thermoregulation. The person's body produces or absorbs more heat than it dissipates. When extreme ...
,
heat exhaustion Heat exhaustion is a severe form of heat illness. It is a medical emergency. Heat exhaustion is caused by the loss of water and electrolytes through sweating. The United States Department of Labor makes the following recommendation, "Heat illness ...
,
heat cramps Heat cramps, a type of heat illness, are muscle spasms that result from loss of large amount of salt and water through exercise. Heat cramps are associated with cramping in the abdomen, arms and calves. This can be caused by inadequate consumption ...
, heat rashes and chronic kidney disease. Although heat exhaustion is less severe, hyperthermia is a
medical emergency A medical emergency is an acute injury or illness that poses an immediate risk to a person's life or long-term health, sometimes referred to as a situation risking "life or limb". These emergencies may require assistance from another, qualified p ...
and requires emergency treatment, which if not provided can even lead to
death Death is the irreversible cessation of all biological functions that sustain an organism. For organisms with a brain, death can also be defined as the irreversible cessation of functioning of the whole brain, including brainstem, and brain ...
. Heat stress causes illness but also may account for an increase in workplace accidents, and a decrease in worker productivity. Worker injuries attributable to heat include those caused by: sweaty palms, fogged-up safety glasses, and
dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical c ...
.
Burn A burn is an injury to skin, or other tissues, caused by heat, cold, electricity, chemicals, friction, or ultraviolet radiation (like sunburn). Most burns are due to heat from hot liquids (called scalding), solids, or fire. Burns occur mainl ...
s may also occur as a result of accidental contact with hot surfaces or steam. In the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, occupational heat stress is becoming more significant as the average temperatures increase but remains overlooked. There are few studies and regulations regarding heat exposure of workers.


Risk factors

Heat-related illnesses from occupational heat stress is impacted by multiple factors. Workers exposed to high temperatures,
humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...
, and limited air movement, especially outside workers, are vulnerable to heat illness.
Physiologic Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical ...
factors can also impact a worker's vulnerability, specifically if their job requires physical exertion, which produces metabolic heat. Workers can also be more vulnerable to heat illness if they are
dehydrated In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...
from
sweating Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distr ...
and not drinking enough water or have a low level of
physical fitness Physical fitness is a state of health and well-being and, more specifically, the ability to perform aspects of Outline of sports, sports, occupations and daily activities. Physical fitness is generally achieved through proper nutrition, moderate ...
. Certain medications can also make it more difficult for someone to adapt to high temperatures, such as some common
antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...
s, as well as some diabetes, cardiovascular disease, and
psychiatric Psychiatry is the medical specialty devoted to the diagnosis, prevention, and treatment of mental disorders. These include various maladaptations related to mood, behaviour, cognition, and perceptions. See glossary of psychiatry. Initial psychi ...
medications. Workers who have
cardiovascular disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, h ...
s, respiratory illnesses,
diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...
,
hypertension Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...
, or
obesity Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's we ...
, or who are currently
pregnant Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...
, are also at higher risk for heat illness. Additionally, wearing heavy or thick
personal protective equipment Personal protective equipment (PPE) is protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury or infection. The hazards addressed by protective equipment include physical, elec ...
and clothing can prevent workers from
sweating Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distr ...
properly, which prevents the body from effectively cooling. Workers can also adjust to working in high temperatures so their bodies can become better at cooling over time, though this adjustment requires a multi-week
acclimatization Acclimatization or acclimatisation ( also called acclimation or acclimatation) is the process in which an individual organism adjusts to a change in its environment (such as a change in altitude, temperature, humidity, photoperiod, or pH), ...
process.


Acclimatization

According to the
National Institute for Occupational Safety and Health The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the C ...
(NIOSH),
acclimatization Acclimatization or acclimatisation ( also called acclimation or acclimatation) is the process in which an individual organism adjusts to a change in its environment (such as a change in altitude, temperature, humidity, photoperiod, or pH), ...
is a biological process that an individual will go through to adjust to a stimulus following continued exposure. Physiologically, acclimatization to heat will allow a worker's body to more efficiently cool itself when exposed to high temperatures. When a worker has adjusted to working in a hotter environment, they will have a lower
heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...
, earlier onset of
sweating Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distr ...
, and increased blood flow to blood
vessels Vessel(s) or The Vessel may refer to: Biology *Blood vessel, a part of the circulatory system and function to transport blood throughout the body *Lymphatic vessel, a thin walled, valved structure that carries lymph *Vessel element, a narrow wat ...
near the skin, allowing their body to more efficiently cool itself than a worker who is not acclimatized. See below section on acclimatization schedules for specific processes.


Examples of high risk occupations

Workers in many occupations are at high risk for exposure to heat stress. Especially vulnerable are outdoor workers who have highly physical tasks to complete, such as
firefighter A firefighter is a first responder and rescuer extensively trained in firefighting, primarily to extinguish hazardous fires that threaten life, property, and the environment as well as to rescue people and in some cases or jurisdictions also ...
s,
miner A miner is a person who extracts ore, coal, chalk, clay, or other minerals from the earth through mining. There are two senses in which the term is used. In its narrowest sense, a miner is someone who works at the rock face; cutting, blasting, ...
s,
military personnel Military personnel are members of the state's armed forces. Their roles, pay, and obligations differ according to their military branch (army, navy, marines, air force, space force, and coast guard), rank (officer, non-commissioned officer, or e ...
,
construction worker A construction worker is a worker employed in the physical construction of the built environment and its infrastructure. Definition By some definitions, workers may be engaged in manual labour as unskilled or semi-skilled workers; they may be sk ...
s,
landscapers Landscaping refers to any activity that modifies the visible features of an area of land, including the following: # Living elements, such as flora or fauna; or what is commonly called gardening, the art and craft of growing plants with a goal o ...
,
athlete An athlete (also sportsman or sportswoman) is a person who competes in one or more sports that involve physical strength, speed, or endurance. Athletes may be professionals or amateurs. Most professional athletes have particularly well-devel ...
s, delivery persons, and agricultural workers. Additionally, many indoor jobs also require high-exertion work in very hot conditions, for example
factory workers A factory, manufacturing plant or a production plant is an industrial facility, often a complex consisting of several buildings filled with machinery, where workers manufacture items or operate machines which process each item into another. T ...
, boiler room workers,
welder In a broad sense, a welder is anyone, amateur or professional, who uses welding equipment, perhaps especially one who uses such equipment fairly often. In a narrower sense, a welder is a tradesperson who specializes in fusing materials together ...
s, and kitchen staff. In unusually hot conditions, all workers should be aware of their risk for heat illness and should ensure they drink plenty of water and take breaks in cool places to avoid any severe impacts.


Symptoms of heat stress

The '
Signs and Symptoms of Heat Illness
'' is intended to acquaint participants with OSHA's guidelines for heat-related injuries on the job. When someone is exposed to hot conditions, they will begin to
sweat Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distribut ...
and have an
increased heart rate Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (su ...
. If they do not drink enough water to replenish the fluid they are sweating out, a worker can become
dehydrated In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...
. This is why drinking extra water while working in hot environments is critical. If workers continually exert themselves in hot environments, they may develop muscle
cramp A cramp is a sudden, involuntary, painful skeletal muscle contraction or overshortening associated with electrical activity; while generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the aff ...
s from sweating too much, which can be helped by taking a break and drinking extra water and
electrolytes An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon di ...
. Additionally, workers can develop
heat rash Miliaria, also called heat rash, sweat rash, or prickly heat, is a skin disease marked by small, itchy rashes due to sweat trapped under the skin by clogged sweat-gland ducts. Miliaria is a common ailment in hot and humid conditions, such as in ...
, which should be treated in a cool place and soothed with powder. For more severe heat illnesses, it is important for workers to be able to identify the differences between
heat exhaustion Heat exhaustion is a severe form of heat illness. It is a medical emergency. Heat exhaustion is caused by the loss of water and electrolytes through sweating. The United States Department of Labor makes the following recommendation, "Heat illness ...
and
heat stroke Heat stroke or heatstroke, also known as sun stroke, is a severe heat illness that results in a body temperature greater than , along with red skin, headache, dizziness, and confusion. Sweating is generally present in exertional heatstroke, ...
in order to protect themselves and their colleagues.


Heat exhaustion

When a person is experiencing
heat exhaustion Heat exhaustion is a severe form of heat illness. It is a medical emergency. Heat exhaustion is caused by the loss of water and electrolytes through sweating. The United States Department of Labor makes the following recommendation, "Heat illness ...
, they will be actively and heavily sweating, though their skin may feel cool and appear pale. If their temperature is taken, it could be normal or slightly high, and their pulse will be fast, but it may be difficult to detect or feel through the skin. Additionally, the person may exhibit a number of different symptoms such as
headache Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches. Headaches can occur as a result ...
s,
muscle cramps A cramp is a sudden, involuntary, painful skeletal muscle contraction or overshortening associated with electrical activity; while generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the af ...
, and
fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
, as well as nausea, vomiting, and in extreme cases, fainting. If a worker is exhibiting these symptoms, it is important that they take a break from work to sit in a cool place, use cool, damp towels on their head and neck to further cooling, and sip water slowly as they recover. If a worker does not recover within an hour or continues to vomit, it is important to seek medical attention for them quickly.


Heat stroke

If a worker begins to feel the signs of
heat stroke Heat stroke or heatstroke, also known as sun stroke, is a severe heat illness that results in a body temperature greater than , along with red skin, headache, dizziness, and confusion. Sweating is generally present in exertional heatstroke, ...
from over
exertion Exertion is the physical or perceived use of energy.Newton's Third Law, Elert, Glenn. “Forces.” ''Viscosity – The Physics Hypertextbook'', physics.info/newton-first/. Exertion traditionally connotes a strenuous or costly ''effort'', resulting ...
in a high temperature environment, they will normally have a very high temperature, which can be measured with a
thermometer A thermometer is a device that temperature measurement, measures temperature or a temperature gradient (the degree of hotness or coldness of an object). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a merc ...
. Their skin could be hot to the touch and damp with sweat, though they will not be actively
sweating Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distr ...
. If their
pulse In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the nec ...
is taken, it will be fast and easy to detect. Outwardly, the worker could show signs of
dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical c ...
and confusion, and they may have digestive discomfort and nausea. In severe cases, workers can pass out. If a worker is displaying these symptoms, it is important to call 911 to get them immediate medical attention. Additionally, helping the person move to a cooler place and covering their head and neck in cool, damp cloths can help while waiting for emergency services to arrive. It is important to wait for a medical professional to see them before asking them to drink a lot of water.


Measurement and monitoring


Measurements

NIOSH has set Wet Bulb Globe Temperature (WBGT)-based Recommended Alert Limits (RALs) for unacclimatized workers and Recommended Exposure Limits (RELs) for acclimatized workers to use in determining, monitoring, and responding to the risk of heat exposure and related impacts. While different ranges of temperatures are used to determine what types of protective action should be implemented, there is no universal safe limit applied across all occupational settings. This is because safety will depend on factors specific to the environments and tasks of a specific job, as well as the workers’ physical health and fitness. There are many different ways to measure temperature. Typically, a
thermometer A thermometer is a device that temperature measurement, measures temperature or a temperature gradient (the degree of hotness or coldness of an object). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a merc ...
can be used to measure environmental
temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...
. However, high
humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...
, or the amount of water that has evaporated into the air in the form of
water vapor (99.9839 °C) , - , Boiling point , , - , specific gas constant , 461.5 J/( kg·K) , - , Heat of vaporization , 2.27 MJ/kg , - , Heat capacity , 1.864 kJ/(kg·K) Water vapor, water vapour or aqueous vapor is the gaseous pha ...
, can often make the temperature outside feel hotter than the measured temperature. To address this, a
heat index The heat index (HI) is an index that combines air temperature and relative humidity, in shaded areas, to posit a human-perceived equivalent temperature, as how hot it would feel if the humidity were some other value in the shade. The result is als ...
measure includes the air's
relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...
, or a measure of how much moisture is in the air compared to if the air were saturated with water vapor. This measure of humidity along with temperature provides more information on what workers should expect to feel in terms of heat if working outside. Additionally, some sources also report
wet-bulb temperature The wet-bulb temperature (WBT) is the temperature read by a thermometer covered in water-soaked (water at ambient temperature) cloth (a wet-bulb thermometer) over which air is passed. At 100% relative humidity, the wet-bulb temperature is equal ...
, which is considered an informative measure for individuals who will be working in direct sunlight. This measure takes into account both temperature and humidity, but also includes measures of
wind speed In meteorology, wind speed, or wind flow speed, is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature. Wind speed is now commonly measured with an anemometer. Wind speed ...
,
cloud cover Cloud cover (also known as cloudiness, cloudage, or cloud amount) refers to the fraction of the sky obscured by clouds on average when observed from a particular location. Okta is the usual unit for measurement of the cloud cover. The cloud co ...
, and angle of the sun at different times of the day. OSHA uses a measure called the Adjusted Air Temperature to determine how often workers should be monitored, which involves the equation: T_a = T+ (13\times \%\text) Where T is temperature measured in degrees Fahrenheit (°F) and percent sunshine is measured on a spectrum from 100% (no clouds, noticeable shadows) to 0% (total cloud cover, no shadows).


Monitoring

OSHA OSHA or Osha may refer to: Work * Occupational Safety and Health Administration, a federal agency of the United States that regulates workplace safety and health * Occupational Safety and Health Act (United States) of 1970, a federal law in the Un ...
recommends monitoring worker's
heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...
,
temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...
, and
body water In physiology, body water is the water content of an animal body that is contained in the tissues, the blood, the bones and elsewhere. The percentages of body water contained in various fluid compartments add up to total body water (TBW). This wa ...
loss throughout shifts in hot conditions. When the adjusted temperature is 90 °F or above, it is recommended that even healthy, acclimatized workers have these measures monitored every 45 minutes. Workers who are not acclimatized or who are wearing impermeable equipment or clothing should be monitored every 15 minutes. NIOSH and OSHA have also created a Heat Index App for mobile devices that provides information on temperature, humidity, risk of heat illness, as well as hourly forecasts of temperature and information on how to prevent and treat heat illnesses.


Prevention

Employers can establish prevention programs, which focus on having protocols to gradually increases workloads and concede on allowing on more breaks for new hired workers. Employers can control heat stress through engineering controls, work practices, providing training, implementing an acclimatization schedule, providing water and encouraging workers to drink often, and ensuring workers take appropriate rest breaks to cool down.


Engineering controls

Employers can provide
air conditioners Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling ...
for indoor work spaces and for indoor break areas. Fans can also be used together with air conditioners, and misting fans can be used outside for added cooling. Additionally, increasing building ventilation and improving the insulation of hot surfaces will reduce indoor temperatures. If all work is completed outdoors, a shaded area should be provided with ample water for workers to take breaks often.


Work practices

Ample breaks with space provided in shaded or cooled areas are important for preventing heat stress related illnesses. Employers should also supply water for workers throughout the day, as workers need to drink more water when working in hot environments than they would otherwise. Additionally, on particularly hot days, limiting high-exertion tasks as much as possible is important for keeping a worker's metabolic temperature down.


Training

All employees should be trained to recognize the '
symptoms of heat stress
''. Supervisors should monitor their employees throughout the day for these symptoms and, for larger teams, a buddy system can be used to group workers to monitor each other for signs of heat illness. Additionally, informing workers about their working conditions and risk of heat illness is important, specifically in making sure that everyone understands what the heat index means and what extra '

'' to take during higher risk periods.


Acclimatization schedules

Acclimatization can occur over different time periods for different people, but NIOSH recommends allowing workers to be exposed to gradually higher levels of heat over 7–14 days for acclimatization. New workers without recent exposure to heat may require additional time to adjust. On the first day of an acclimatization process, workers without previous heat exposure should be asked to complete, at most, 20% of their typical workday. After this, their workload can increase by 20% for each day of the process. For workers with previous exposure working in high temperature settings, acclimatization can occur as fast as four days, starting with workers completing 50% of their typical work duration on the first day. NIOSH strongly suggests that workers who are currently adjusting to new conditions should be supervised closely for signs of
heat stress Hyperthermia, also known simply as overheating, is a condition in which an individual's body temperature is elevated beyond normal due to failed thermoregulation. The person's body produces or absorbs more heat than it dissipates. When extreme ...
, especially those who may adjust slower due to age, pre-existing health conditions, or lower levels of
physical fitness Physical fitness is a state of health and well-being and, more specifically, the ability to perform aspects of Outline of sports, sports, occupations and daily activities. Physical fitness is generally achieved through proper nutrition, moderate ...
. A worker's level of acclimatization must also be maintained, and if workers are absent from the working conditions for more than a week, they will need to begin the acclimatization process again.


Occupational standards


International

International Organization for Standardization The International Organization for Standardization (ISO ) is an international standard development organization composed of representatives from the national standards organizations of member countries. Membership requirements are given in Ar ...
helps set standards for monitoring environments, analyzing data, and interpreting results.


United States

Section 5(a)(1) of the
Occupational Safety and Health Act The Occupational Safety and Health Act of 1970 is a US labor law governing the federal law of occupational health and safety in the private sector and federal government in the United States. It was enacted by Congress in 1970 and was signed by P ...
of 1970 declares that "Each employer shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees." The
Mine Safety and Health Administration The Mine Safety and Health Administration (MSHA) () is a large agency of the United States Department of Labor which administers the provisions of the Federal Mine Safety and Health Act of 1977 (Mine Act) to enforce compliance with mandatory safet ...
provides guidelines and recommendations to employers for preventing heat stress among workers. There guidelines and recommendations are not enforced regulations, but instead completely voluntary. National Institute for Occupational Safety and Health (NIOSH) conducts research on occupational hazards such as heat stress in order to provide better intervention methods and protect workers. Only three of the fifty states have created worker regulations regarding heat: California, Washington, and Minnesota. California Code of Regulations states that employers of high risk outdoor workers are entitled to protection against heat. The employer must provide access to water and shade, practice high heat procedures, practice emergency response procedures, and practice acclimatization methods. Washington State Legislature states that employers of high risk outdoor workers follow regulations to prevent heat stress. Minnesota Administrative Rules state that indoor ventilation and temperature are regulated to prevent heat stress.


NIOSH recommended standard

Beginning in 1972, NIOSH published a recommended standard for hot work environments, and has periodically revised to take new scientific findings into account. The intent of the NIOSH Recommended Standard for Occupational Exposure to Heat and Hot Environments is to prevent injury, disease, death, and reduced productivity. The recommendations include workplace limits and surveillance, medical monitoring, surveillance of heat-related sentinel health events, posting of hazardous areas, protective clothing and equipment, worker information and training, control of heat stress, and record keeping.


= Control of heat stress

= Control of heat stress has recommended general requirements, engineering controls, work and hygienic practices, and a heat alert program.


General Requirements

NIOSH The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the C ...
recommends that every employer should create and implement a written program aimed at reducing heat exposures. Engineering and work practice controls should be used to reduce exposures, and a heat alert program should be implemented.


Engineering Controls

Air temperatures should be reduced so it does not exceed skin temperatures.
Radiant heat Thermal radiation is electromagnetic radiation generated by the thermal motion of particles in matter. Thermal radiation is generated when heat from the movement of charges in the material (electrons and protons in common forms of matter) is ...
should be reduced by creating barriers around the source. Evaporative heat loss can be increased by increasing air movement around the worker.


Work and Hygienic Practices

The time workers spend in hot environments should be limited, with an increase of recovery time spent in cool environments. Use of more efficient procedures and tools is beneficial to reducing metabolic demands of the job. Heat tolerance may be increased by implementing a heat tolerance plan and increasing physical fitness. Employees should be trained to recognize and treat the early signs and symptoms of heat illnesses, and employers should provide cool water for employees.


Heat Alert Program

Heat alert programs should be developed for implementation when hotter than normal temperatures, or a
heat wave A heat wave, or heatwave, is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is usually measured relative to the usual climate in the ...
occurs.


See also

*
Heat exhaustion Heat exhaustion is a severe form of heat illness. It is a medical emergency. Heat exhaustion is caused by the loss of water and electrolytes through sweating. The United States Department of Labor makes the following recommendation, "Heat illness ...
*
Heat stroke Heat stroke or heatstroke, also known as sun stroke, is a severe heat illness that results in a body temperature greater than , along with red skin, headache, dizziness, and confusion. Sweating is generally present in exertional heatstroke, ...
*
Dehydration In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...
*
Heat Index The heat index (HI) is an index that combines air temperature and relative humidity, in shaded areas, to posit a human-perceived equivalent temperature, as how hot it would feel if the humidity were some other value in the shade. The result is als ...


External links


Working in heat
Safe Work Australia
First aid for heat-related illness
Safe Work Australia

CDC


References

{{Occupational safety and health Occupational safety and health Public health Environment and health Climate