Keys to protecting mine workers from heat stress

Heat stress is a major cause for concern among many workers in the U.S. 

Miners are among the many experiencing an increase in adverse health effects from heat exposure as surface temperatures get hotter and underground mines get deeper. Researchers from the National Institute for Occupational Safety & Health (NIOSH) are conducting studies to better understand heat stress, its effects on miners and how to protect them. 

Heat stress impacts

Heat stress is the total amount of heat someone is exposed to from the environment. Heat strain, meanwhile, is the body’s response to heat stress. And without proper prevention strategies, excessive heat exposure can lead to heat-related illnesses. 

Several common heat-related illnesses are heat rash, muscle cramps, fainting, heat exhaustion and heat stroke. Research indicates that occupational heat exposure can lead to organ damage, such as chronic kidney disease. 

Additionally, studies suggest a link between heat exposure and work injuries. This research suggests that work injuries – including slips, trips and falls – could be related to hot working conditions. 

The underlying causes of this relationship are not known, but some researchers suggest they are due to a combination of physical discomfort, fatigue, decreased psychomotor function and decreased cognition. 

Changes in cognition alone are also associated with heat strain. This is concerning because miners use several cognitive skills throughout the workday. For instance, mine workers must be vigilant and stay focused on tasks, recognize and react to hazards, and avoid distractions. 

By learning more about heat exposure effects on mine workers’ cognition, NIOSH researchers can better understand how heat-impaired cognition can play a role in some of the most common injuries in mining. Strategies to potentially control those injuries by reducing the effects of heat on cognition can then be developed. 

According to the Centers for Disease Control & Prevention, sand and gravel pit workers experience nonfatal injuries most often while handling materials or because of slips, trips or falls. Heat exposure can impair concentration, attentiveness and reaction time, which can, in turn, increase a worker’s likelihood of injury while handling materials. 

Similarly, decreased concentration or attentiveness can contribute to slips, trips or falls if a worker is distracted and has a slower reaction time. 

The consequences of heat stress can affect more than just mine workers’ health and safety. Injuries, illness and employee turnover due to heat stress can impact a mining company’s bottom line. 

Research shows, in general, unhealthy workers are less productive. Therefore, both mine workers and mining companies can benefit by identifying effective ways to manage exposure to heat and limit heat stress. Implementing preventive heat stress protocols in the workplace can ensure the health and safety of mine workers and provide a fiscally driven strategy to reduce employee turnover and increase productivity by preventing heat-related illnesses.

Preventing heat stress 

While NIOSH researchers continue to study the impact of heat on the mining workforce to identify novel ways to reduce heat strain at mine sites, there are strategies available now for mine workers to use and for frontline supervisors to incorporate into health and safety plans. 

Frontline supervisors should make a few considerations when assigning work and evaluating the workplace. For example, understand environmental factors such as high temperature, humidity and direct sun exposure. Also, understand personal risk factors like increased body mass index and dehydration, as these increase risk for heat-related illness and injury. 

Supervisors should ensure those working in heat are adequately acclimatized, and remember that acclimatization can be lost quickly during time off. Workers can start to lose acclimatization after about a week.

Workers should consider the following strategies to reduce the risk of heat strain while working: 

• Take frequent rest breaks to cool off.

• Drink water regularly, and do not wait until you are thirsty to drink.

• Eat regular meals to replace lost electrolytes.

• Monitor yourself and co-workers for symptoms associated with heat illness, and take action immediately at the onset of any symptoms.

• Continue to drink water after work to ensure hydration before the next shift.

Alex Johnson, Kristin Yeoman and Brianna Eiter wrote this article on behalf of the National Institute for Occupational Safety & Health (NIOSH). The findings and conclusions presented in this article are those of the authors and do not necessarily represent the official position of NIOSH. Mention of any company or product does not constitute endorsement by NIOSH.