Occupational heat stress
Occupational heat stress is the net load to which a worker is exposed from the combined contributions of metabolic heat, environmental factors, and clothing worn which results in an increase in heat storage in the body. Heat stress can result in heat-related illnesses, such as heat stroke, hyperthermia, heat exhaustion, heat cramps or heat rashes. Although heat exhaustion is less severe, hyperthermia is a medical emergency and requires emergency treatment, which if not provided can even lead to death.
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. Burns may also occur as a result of accidental contact with hot surfaces or steam. In the United States, 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.
Heat-related illnesses from occupational heat stress have several risk factors. Some of these factors include high temperatures, humidity, radiant heat sources, limited air movement, metabolic heat from physical exertion of energy, not drinking enough fluids, personal protective equipment and clothing, physical condition and health problems, medications, pregnancy, lack of acclimatization, advanced age, having a previous heat-related illness and others.
Examples of high risk occupations
Workers in many occupations are at high risk for exposure to heat stress. Some of the higher risk occupations include firefighter, bakery worker, miner, military personnel, construction worker, factory worker, boiler room worker, landscaper, some athletes and agricultural worker.
Symptoms of heat stress
The main symptoms of heat stress are perspiration, increased heart rate, and dehydration. Other general symptoms include painful muscle cramps, extreme weakness, nausea, dizziness, headache, breathing fast and clammy, pale, cool, and/or moist skin or red, dry skin. 
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.
Section 5(a)(1) of the Occupational Safety and Health Act 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 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.
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.
NIOSH 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.
Air temperatures should be reduced so it does not exceed skin temperatures. Radiant heat 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
- "NIOSH Criteria for a Recommended Standard: Occupational Exposure to Heat and Hot Environments". 2016. doi:10.26616/NIOSHPUB2016106. Cite journal requires
- "CDC - Heat Stress - NIOSH Workplace Safety and Health Topic". www.cdc.gov. Retrieved 2016-04-15.
- "CDC - Heat Stress - Heat Related Illness - NIOSH Workplace Safety and Health Topic". www.cdc.gov. Retrieved 2016-03-21.
- Lucas, Rebekah A I; Epstein, Yoram; Kjellstrom, Tord (2014-07-23). "Excessive occupational heat exposure: a significant ergonomic challenge and health risk for current and future workers". Extreme Physiology & Medicine. 3 (1): 14. doi:10.1186/2046-7648-3-14. PMC 4107471. PMID 25057350.
- Gubernot, Diane M.; Anderson, G. Brooke; Hunting, Katherine L. (2013-12-11). "The epidemiology of occupational heat exposure in the United States: a review of the literature and assessment of research needs in a changing climate". International Journal of Biometeorology. 58 (8): 1779–1788. doi:10.1007/s00484-013-0752-x. ISSN 0020-7128. PMC 4145032. PMID 24326903.
- "California Code of Regulations, Title 8, section 3395 Heat Illness Prevention". www.dir.ca.gov. Retrieved 2016-03-21.
- Aastrand, Irma (1975). "Heat Stress in Occupational Work". Royal Swedish Academy of Sciences and Springer.
- "Heat Illness Prevention - Title 8 Section 3395". www.dir.ca.gov. Retrieved 2016-05-10.
- "OSHA's Campaign to Prevent Heat Illness in Outdoor Workers". www.osha.gov. Retrieved 2016-05-10.
- "CDC - Heat Stress - Recommendations - NIOSH Workplace Safety and Health Topic". www.cdc.gov. Retrieved 2017-02-01.
- Parsons, Ken (2013-01-01). "Occupational Health Impacts of Climate Change: Current and Future ISO Standards for the Assessment of Heat Stress". Industrial Health. 51 (1): 86–100. doi:10.2486/indhealth.2012-0165. PMID 23411759.
- "OSHA Content Document". www.osha.gov. Retrieved 2016-03-21.
- "Heat Stress - Safety Manual Number 6". arlweb.msha.gov. Archived from the original on 2016-03-07. Retrieved 2016-03-21.
- "CDC - Occupational Exposure to Heat and Hot Environments - NIOSH Publications & Products". www.cdc.gov. 2016. doi:10.26616/NIOSHPUB2016106. Retrieved 2016-04-21.