A New Study Examines the Impact of Extreme Heat Waves on Health of Outdoor Workers

Working outdoors during phases of extreme heat can result in heat stress, discomfort, or heat illnesses—all growing issues for people who reside and work in Southwestern cities in the United States, such as Las Vegas, where temperatures in summer are gradually increasing each year. 

A New Study Examines the Impact of Extreme Heat Waves on Health of Outdoor Workers.
According to new research, the number of heat-related nonfatal workplace injuries in Arizona, California, and Nevada increased between 2011 and 2018. The three states now exceed the U.S. average. Image Credit: Erick Bandala/DRI.

Interestingly, female outdoor workers are experiencing disproportionate impacts, and skilled outdoor workers are at greater risk than those with fewer years of outdoor work.

In research recently published in the International Journal of Environmental Science and Technology, researchers from Desert Research Institute (DRI), Nevada State College, and the Guinn Center for Policy Priorities investigate the increasing threat that extreme heat poses to workers’ health in three of the hottest cities in the US — Los Angeles, Las Vegas and Phoenix.

Their results present crucial findings for outdoor workers, their employers and policymakers across the Southwestern US.  

To measure the connection between extreme heat and nonfatal workplace heat-associated sickness, the researchers compared data on occupational illnesses and injuries between the years 2011 and 2018 with heat index data from Los Angeles, Las Vegas, and Phoenix. Heat index data integrates humidity and temperature as a measure of how people experience the heat.

“We expected to see a correlation between high temperatures and people getting sickand we found that there was a very clear trend in most cases,” said the study’s lead author Erick Bandala, Ph.D., assistant research professor of environmental science at DRI. “Surprisingly, this type of analysis hadn’t been done in the past, and there are some really interesting social implications to what we learned.”

Initially, the researchers examined variations in the heat index data for the above-mentioned cities. They found a substantial increase in the heat index of two of the three regions (Las Vegas and Phoenix) during the research period, with average heat index values for June-August increasing from “extreme caution” in 2012 into the “danger” range by 2018.

During the same timeline, data from the Bureau of Labor and Statistics revealed that the number of nonfatal heat-connected workplace illnesses and injuries in each of the three states grew progressively, increasing from below the national average in 2011 to beyond the national average in 2018. 

Our data indicate that the increases in heat are happening alongside increases in the number of nonfatal occupational injuries across these three states. Every year we are seeing increased heat waves and higher temperatures, and all of the people who work outside in the streets or in gardens or agriculture are exposed to this.

Erick Bandala, Ph.D., Study Lead Author and Assistant Research Professor of Environmental Science, DRI

Next, the researchers explored the data more deeply to learn about the number of male and female workers being impacted by heat-associated workplace injuries. At the commencement of the research in 2011, 26 to 50% of the workers impacted across the three states were female. By 2018, 42-86% of the workers impacted were female.

The researchers believe that this increase could be because of more women joining the outdoor workforce, or it could be connected to the susceptibility of women to specific heat-related effects, such as hyponatremia — a condition that crops up when excess plain water is drunk under high heat scenarios and sodium levels in the blood become very low.

As the number of female workers exposed to extreme temperatures increases, there is an increasing need to consider the effect of gender and use different approaches to recommend prevention measures as hormonal factors and cycles that can be exacerbated during exposure to extreme heat.

Kebret Kebede, M.D., Study Co-Author and Associate Professor of Biology, Nevada State College

The researchers analyzed other components, such as the service period of an employee with an employer. They learned that the number of heat-connected illnesses/injuries tended to climb as the length of service with the employer grew and that those with over 5 years of service were at higher risk compared to those with less than 1 year of service.

This may be because employees with more years of service have a lower perception of risk, or could be a cumulative influence of years of prolonged heat exposure on the well-being of outdoor workers.

In extreme cases, heat-associated injury or illness can cause widespread damage to all tissues and organs, upsetting the blood-clotting mechanisms, central nervous system, and liver and kidney operations. In such cases, prolonged recoveries are necessary. The researchers found unsettling evidence that heat-linked injuries are causing a number of outdoor workers to stay away from work for over 30 days.

These lengthy recovery times are a significant problem for workers and their families, many of whom are living day-to-day. When we have these extreme heat conditions coming every year and a lot of people working outside, we need to know what are the consequences of these problems, and we need the people to know about the risk so that they take proper precautions.

Erick Bandala, Ph.D., Study Lead Author and Assistant Research Professor of Environmental Science, DRI

The research also investigated links between heat-associated illnesses/injuries and the number of hours clocked by workers, the time of day that the event transpired, and the age groups and ethnicities that were most affected.

The researchers hope that their findings will be beneficial to policymakers to safeguard outdoor workers. They also anticipate that the data will be beneficial to outdoor workers who need to keep safe during phases of extreme heat, and employers who depend on a healthy workforce to keep their companies running.

 “This study underscores the importance of and the need for the work the Nevada Occupational Safety and Health Administration (OSHA) is doing to adopt a regulation to address heat illness,” stated Nancy Brune, Ph.D., study co-author and senior fellow at the Guinn Center. 

As temperatures continue to rise and heat-related illnesses and deaths continue to rise, the need for public policies to alleviate health and economic impacts is growing. I hope to continue doing research on this problem so that we can have a better of understanding of the impacts of extreme heat and how to help the people who are most vulnerable.

Erick Bandala, Ph.D., Study Lead Author and Assistant Research Professor of Environmental Science, DRI

Journal Reference:

Bandala, E. R., et al. (2022) Assessing the effect of extreme heat on workforce health in the southwestern USA. International Journal of Environmental Science and Technology. doi.org/10.1007/s13762-022-04180-1.

Source: https://www.dri.edu

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