Assessing worker exposure in conditions that may present a heat hazard is critical for knowing when to implement a heat-related illness prevention program.
This OSHA Technical Manual (OTM) chapter provides technical information about indoor and outdoor heat hazards, illnesses, and prevention methods across all industries.
The information will help to prepare OSHA compliance officers to conduct inspections and investigations.
Specifically, this chapter provides technical information about using Wet Bulb Globe Temperature (WBGT) measurements to determine when heat exposure hazards are present in the workplace.
Many risk factors contribute to the risk for heat-related illness (see Figure 1.).
A heat-related illness occurs when there is an increase in the workers core body temperature above healthy levels.
As core temperature rises, the body is less able to perform normal functions.
As core temperature continues to increase, the body releases inflammatory agents associated with damage to the liver and muscles.
Physical exertion, environmental factors, and clothing worn all contribute to heat stress.
When these are not enough to keep the core body temperature from rising, the result is heat-related illness or death.
Elevated core body temperatures may cause the following illnesses.
Heat stroke occurs when the body becomes unable to adequately dissipate heat, losing the ability to regulate core body temperature.
The core body temperature rises rapidly, the sweating mechanism may fail, and the body is unable to cool down.
When heat stroke occurs, the body temperature can rise to 41oC (106F) or higher within 10 to 15 minutes.
Thinking clearly, perception, planning, and other mental processes become impaired, and the worker may be unable to recognize dangerous situations.
How to use cheats on dolphin emulator macHeat stroke can cause death or permanent disability if emergency medical treatment is not given.
Symptoms include confusion, clumsiness, slurred speech, faintingunconsciousness, hot dry skin, profuse sweating, seizures, and high body temperature.
It is often accompanied by elevated core body temperatures around 38C39C (100.4F102.2F).
Symptoms may include headache, nausea, dizziness, fatigue, weakness, thirst, heavy sweating, irritability, and a decreased urine output.
The symptoms include spastic contractions and pain in voluntary muscles mainly in the arms, legs, or torso.
Heat syncope symptoms include light-headedness, dizziness, and fainting.
Dehydration and inadequate acclimatization often contribute to heat syncope.
Excessive moisture and sweat obstructs sweat ducts and forms itchy and painful red pimpleblister clusters and skin lesions.