Health and Wellness, Heat illness, Personnel Safety, Training

Understanding Heat Stress and Prevention Strategies

As heat stress increasingly becomes a focus for the federal government, it’s still incumbent upon businesses to understand how to properly protect their workers from the heat.

Speaking at the National Safety Council’s 2022 NSC Safety Congress & Expo in San Diego last month, two experts detailed heat stress prevention strategies, staff education and training, and how to recognize when workers are suffering from heat stress.

“Any time you’re working in a hot environment, the potential for injury goes up,” said Matthew Block, director of health and safety services for Magid Glove. Eleven workers are seriously injured or die every day from heat stress. Occupational heat stress can cause a variety of ailments: Heat illness (hyperthermia), kidney injury, fatigue, fall and injury risk, dehydration, and cardiac strain.

Dehydration is a major factor in heat stress, and a recent study found that 70% of workers examined were dehydrated on arrival at work, said Margaret Morrissey, president of the Heat Safety & Performance Coalition (HSPC, formerly known as the National Heat Safety Coalition) and director of occupational and military safety at the Korey Stringer Institute.

“If you start out dehydrated and the work is in a difficult environment, that can contribute significantly to hyperthermia,” Block added. “By taking steps to prevent heat stress, we believe you would not only avoid risks, you could increase productivity.”

The cost for a heat safety incident is about $80,000 in direct and indirect costs. In the U.S., there is $100 billion per year in lost productivity due to heat-related incidents.

OSHA is paying attention. In April, OSHA launched a National Emphasis Program on indoor and outdoor heat hazards. OSHA can proactively inspect 70 high-risk industries; it conducted 1,500 inspections from April to September. OSHA is focusing on acclimatization, monitoring and understanding symptoms, and reducing heat injuries indoors.

A federal heat safety standard is in the works and HSPC was selected as one of the key stakeholders, said Morrissey. The group provided a 56-page report to be considered in the process. In addition, the American Society of Safety Professionals is creating a voluntary standard, which is being reviewed and should be out in the next year.

Consensus document provides strategies

Morrissey cited a July 2021 consensus document, Heat Safety in the Workplace: Modified Delphi Consensus to Establish Strategies and Resources to Protect the US Workers, as a good source of information on heat stress prevention. The document includes 40 evidence-based recommendations to protect workers from heat.

“There’s a lot of recommendations you may see out there, but a lot of them aren’t evidence-based,” she noted. The roundtable that developed the document included Morrissey and 50 other experts from governing bodies such as NIOSH and the U.S. Army, as well as scientists, clinicians, and safety managers.

The roundtable’s heat illness prevention strategies include the following:

  • Heat hygiene practices
  • Hydration
  • Heat acclimatization
  • Environmental monitoring
  • Physiological monitoring
  • Body cooling
  • Textiles/personal protective equipment (PPE)
  • Emergency Action Plan implementation and procedures

Heat safety education and training is crucial and should include:

  • Risk factors of heat-related illnesses and injury
  • Heat-related illness prevention strategies
  • First aid
  • Emergency response procedures for heat illnesses

This training “needs to be an ongoing process, at onboarding and annual,” Morrissey said.

Another important component is having an emergency action plan. Each worksite needs an emergency action plan that addresses what will be done during medical emergencies associated with heat stress, she said. It must be disseminated to all staff, reviewed carefully, and rehearsed. Businesses need to identify a worksite manager and medical personnel who will create, manage, coordinate, and execute the plan.

To evaluate your company’s level of heat safety preparedness, Morrissey recommends having an organization like the HSPC come in to do a heat safety assessment. A good heat safety assessment should include the following:

  • On-site visit
  • One to three days of observation
  • Review of written heat policy and emergency action plans for heat
  • Interview with safety staff, medical staff, workers, other key stakeholders
  • Closing meeting with preliminary findings and recommendations
  • Comprehensive report on heat safety recommendations
  • Quarterly follow-up meetings

Identifying heat hazards

Morrissey detailed how to identify heat as a hazard through the following:

  • Environmental conditions
  • Physically demanding work
  • Insulating PPE
  • Limited rest breaks
  • Reported symptoms of heat strain, heat illness, heat injury, exertional heat stroke
  • Individual characteristics

Conditions that may be associated with heat intolerance include the following:

  • Sedentary lifestyle
  • Type 1 and 2 diabetes
  • Hypertension
  • Heart disease
  • Autonomic dysfunction (dysfunction of the autonomic nervous system that is in control of automatic, unconscious, and involuntary functions of the body)
  • Kidney disease
  • Medications that affect thermoregulation, central nervous system function, sodium balance
  • Obesity
  • Pregnancy

The following risk factors can lead to heat illnesses:

  • High temperature and humidity
  • Low fluid consumption
  • Direct sun exposure
  • Limited air movement
  • Heavy physical exertion
  • Poor workplace regulations
  • Bulky protective clothing and equipment
  • Smoking and tobacco use
  • Poor diet
  • Use of prescribed drugs and medications
  • Use of non-prescription and over-the-counter drugs, supplements
  • Sleep deprivation
  • Excessive caffeine
  • Individual characteristics (disease state, body fat)

Promoting heat hygiene practices

Preventing heat stress requires more than just hydration, Morrissey said.

“Hydration is the most utilized prevention strategy,” she said. “The biggest misconception is hydration alone can relieve heat stress.”

Fluids have to be accessible in order for workers to use and drink them. “We really need simple ways to determine that you’re hydrated or not,” Morrissey said. “If you’re thirsty at that point, you’re already dehydrated.”

Heat acclimatization, or gradually and progressively introducing workers to hot conditions, is an underutilized strategy, Morrissey said. Initial heat acclimatization protocol is to increase heat exposure over five to seven days, but she added that there’s not lot of research available about appropriate heat acclimatization protocol.

Body cooling effectiveness tips

When you’re trying to cool down a worker who is experiencing heat stress, Morrissey suggests the following:

  • Cover as much body surface area as possible
  • Make sure your cooling product is cool, not hot.
  • Do you have access to power?
  • Do your workers wear PPE that would impede a body cooling strategy?

Cold water immersion is the gold standard treatment for heat stroke, she said. Core temperature must be obtained to diagnose heat stroke.

“The number one goal is to get core body temperature down within 30 minutes,” said Morrissey. “If someone is aggressively cooled within 30 minutes, they can recover without long-term effects.”

Other options include using a tarp to serve as a makeshift pool or products like Polar Life Pods, which are portable, collapsible immersion systems that can facilitate the rapid cooling of a person.

Morrissey said there are two levels of prevention:

  • Preventing heat-related injury or illness from happening in the first place.
  • Preventing heat-related fatality: Nothing is 100% failproof. Be prepared to recognize and treat exertional heat stroke.

The signs and symptoms of exertional heat stroke include:

  • Extreme hyperthermia (greater than 105 degrees F): Dizziness
  • Altered consciousness: Headache
  • Disorientation: Nausea
  • Confusion: Muscle cramps
  • Vomiting: Dehydration
  • Staggering: Irritability/combative
  • Decreased performance: Muscle weakness
  • Profuse sweating: Irrational behavior