Safety in the Heat

Laura Lott MIS CSP

UMD Environmental Health and Safety Office

218-726-6917 desk / 218-721-2051 cell

What Is the Deadliest Weather Hazard?

• Thunderstorms
• Tornadoes
• Floods
• Heat
• Lightning
• Hail
• Damaging Winds
• Winter Weather

Except for heat-related fatalities, more deaths occur from flooding than any other weather-related hazard

Heat related deaths have been increasing in the US, with approximately 1,602 occurring in 2021, 1,722 in 2022, and 2,325 in 2023.

Heat Related Emergency Room Visits�United States, May-September 2023

• Unprecedented heat waves can affect all persons, but some are more sensitive to the effects of heat:
• Children and adults with underlying health conditions
• Pregnant women
• Outdoor workers
• Increased visits for demographic group, males aged 18-64 years
• High prevalence of visits observed in working-aged adults

​

​

​

​

​

​

Occupational Standards

• Currently, OSHA does not have a specific standard for hazardous heat exposure
• General Duty Clause
• October 26, 2021 “Record-breaking heat in the US in 2021 endangered millions of workers exposed to heat illness and injury in both indoor and outdoor work environments……OSHA….begins the process to consider a heat-specific workplace rule.”
• Beginning April 8, 2022, OSHA staff members will be out in force inspecting on high risk days (forecasted heat indexes of 80-degrees F or higher)
• OSHA’s Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings rule was published in the Federal Register August 30, 2024 and an informal public hearing is occurring June 16, 2025
• NIOSH has a recommended standard for occupational heat stress
• Minnesota rule 5202.0110 Indoor Ventilation and Temperature in Places of Employment

​

Since this instruction, OSHA has conducted nearly 7,000 federal heat-related inspections

Question

• What is the process of gradually exposing your body to heat over time, allow it to adapt and increase its tolerance to heat stress called?

​

Acclimatization

Administrative Controls & Work Practices

• Knowledge of the hazards of heat stress
• Recognition of predisposing factors, danger signs, and symptoms
• Awareness of first-aid procedures for, and the potential health effects of, heat stroke
• Employee responsibilities in avoiding heat stress

Administrative Controls & Work Practices

• Dangers of using drugs, including therapeutic ones, and alcohol in hot work environments
• Use of protective clothing and equipment
• Coverage of environmental surveillance programs and the advantages of worker participation in such programs �

​

Question

• Name the primary means by which a human body maintains a constant body temperature.

​

Sweating

Causal Factors

• Age, weight, degree of physical fitness

​

• Degree of acclimatization, metabolism

​

• Use of alcohol or drugs, and a variety of medical conditions such as hypertension all affect a person's sensitivity to heat

​

Causal Factors

• The type of clothing worn must be considered
• Prior heat injury predisposes an individual to additional injury.

​

Hot Weather Clothing

• Lightweight
• Natural fibers
• When in the sun
• Cover up
• Lighter colors
• No tight fitting clothing
• Still need to wear required PPE

​

​

​

Heat Disorders & Health Effects

• Heat Stroke
• Heat Exhaustion
• Heat Cramps
• Heat Collapse
• Heat Rashes
• Heat Fatigue

​

​

Heat Stroke

• Occurs when the body's system of temperature regulation fails and body temperature rises to critical levels
• This condition is caused by a combination of highly variable factors, and its occurrence is difficult to predict
• Heat stroke is a medical emergency

Stroke - Primary Signs & Symptoms

• Confusion; irrational behavior; loss of consciousness; convulsions
• Lack of sweating (usually); hot, dry skin; and an abnormally high body temperature, e.g., an internal temperature of 105.8°F
• If body temperature is too high, it causes death

​

​

​

Stroke - Treatment

• Professional medical treatment should be obtained immediately. The worker should be placed in a shady area and the outer clothing should be removed.
• The worker's skin should be wetted and air movement around the worker should be increased to improve evaporative cooling until professional methods of cooling are initiated and the seriousness of the condition can be assessed. Fluids should be replaced as soon as possible

​

Heat Exhaustion

• Signs and symptoms
• Headache, nausea, vertigo, weakness, thirst, and giddiness

​

​

Heat exhaustion - Treatment

• Remove from the hot

environment and given fluid replacement

​

• They should also be encouraged to get adequate rest

​

Heat exhaustion - Concerns

• Heat exhaustion should not be dismissed lightly for several reasons
• Fainting associated with heat exhaustion can be dangerous because the victim may be operating machinery or controlling an operation
• Victim may be injured when he or she faints

​

​

Heat Cramps

• Caused by performing hard physical labor in a hot environment. These cramps have been attributed to an electrolyte imbalance caused by sweating
• It is important to understand that cramps can be caused by both too much and too little salt

​

​

Heat Cramps

• Thirst cannot be relied on as a guide to the need for water; instead, water must be taken every 15 to 20 minutes in hot environments

​

Heat cramps - Treatment

• Under extreme conditions, such as working for 6 to 8 hours in heavy protective gear, a loss of sodium may occur
• Recent studies have shown that drinking commercially available carbohydrate-electrolyte replacement liquids is effective in minimizing physiological disturbances during recovery

​

Heat collapse "Fainting"

• In heat collapse, the brain does not receive enough oxygen because blood pools in the extremities
• the onset of heat collapse is rapid and unpredictable

Heat collapse - Prevention

• The worker should gradually become acclimatized to the hot environment

​

Heat Rashes

• Most common problem in hot work environments
• Prickly heat is manifested as red papules and usually appears in areas where the clothing is restrictive

​

Heat Rashes

• Prickly heat occurs in skin that is persistently wetted by unevaporated sweat,
• Heat rash papules may become infected if they are not treated
• In most cases, heat rashes will disappear when the affected individual returns to a cool environment. �

​

​

Heat Fatigue

• A factor that predisposes an individual to heat fatigue is lack of acclimatization

​

Heat fatigue Signs & Symptoms

• The signs and symptoms of heat fatigue include impaired performance of skilled sensor motor, mental, or vigilance jobs

​

Output & Productivity

Heat Index

NWS HeatRisk

Wet Bulb Globe Temperature

• A measure of expected heat stress on the human body in direct sunlight.
• Wet Bulb reads temperature by a thermometer covered in a wet cloth
• Black Globe is used to measure solar radiation
• Dry Bulb calculates the air temperature measured in the shade (what you see on your thermometer)
• HSRM can use a WBGT to evaluate heat stress using a calculation

​

Minnesota Indoor Places of Employment

• Workplace Evaluation of Heat Stress
• Employees shall not be exposed to indoor environmental heat conditions in excess of the values listed below. If these temperatures cannot be maintained as described,
• Work is discontinued in the space until temperatures can be maintained below respective WBGT value for work activity occurring in the space
• HSRM recommends a work-rest cycle based on WBGT measurement and guidelines from ACGIH if work is deemed essential

Question

• Has HSRM had to calculate WBGT and/or recommend a work-rest cycle at the University?

​

Yes

Heat Illness Prevention

• Engineering controls (ventilation, shielding, shaded areas, increase airflow)
• Self monitoring
• Hydration
• Acclimation and Work-Rest Cycles
• PPE (Water/Air-Cooled Garments, Cooling Vests, Heat Reflective Clothing)
• Coveralls and Respiratory Protection will increase your risk for heat-related illnesses

​

​

Self Monitoring Urine Color

1-3: You are hydrated. Continue to drink fluids at the same rate.

4-8: You are DEHYDRATED!

You need to drink more water or electrolyte drinks.

Hydration

• Drink water from the get go. Don’t wait for breaks.
• Frequently drink small amounts of water or electrolyte drink.
• Quart per hour, up to 12 quarts per day

​

Establish Safe Habits

Review

• Knowledge of the hazards of heat stress
• Recognition of predisposing factors, danger signs, and symptoms
• Awareness of first-aid procedures for, and the potential health effects of, heat stroke
• Employee responsibilities in avoiding heat stress
• Employee rights when working in the heat
• Resources/tools to help you prepare for the heat

​

OSHA-National Emphasis Program

…to protect employees from heat-related hazards and resulting injuries and illnesses in outdoor and indoor workplaces.

EHSO-Personal Emphasis Program

…to protect people from heat-related hazards and resulting injuries and illnesses in outdoor and indoor activities both at, and away from, the workplace.