Hazard Zone: The Impact of Climate Change on Occupational Health

Global climate change has the potential to affect human health in two significant ways: by changing the severity and frequency of health issues already affected by climate factors, and by creating unprecedented health threats in places where they have not previously occurred. Studies show that global warming will likely amplify health and safety issues for a number of worker populations. According to “An Overview of Occupational Risks from Climate Change,” published by faculty from the Milken Institute School of Public Health at the George Washington University (Kate ApplebaumJay GrahamGeorge GrayPeter LaPumaSabrina McCormickAmanda Northcross and Melissa Perry), the most likely climate change-related health threats include exposure to heat, ozone, pathogens, infectious diseases, polycyclic aromatic hydrocarbons, wildfires and workplace violence.

Outdoor workers from occupational sectors that include agriculture, construction, transportation, oil production, landscaping, firefighting and other emergency response operations are often among the first to be affected by climate change. Individuals exposed to hot indoor work environments, such as steel mills, dry cleaners, manufacturing facilities, commercial kitchens and warehouses, are also at risk for climate change impacts, including extreme heat exposure and indoor air pollutants. 

The threat to occupational health in the U.S. has far-reaching implications for our economy, too. A 2010 study found that “sub-optimal environmental conditions do more than simply make workers uncomfortable”—they impact work intensity and duration, which in turn affects productivity. The result? Climate change has the potential to “influence all economic sectors, even those previously thought to be insensitive to climate.”

Hazard Zone: The Impact of Climate Change on Occupational Health

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Increased Heat Exposure and Decreased Air Quality

Possibly the greatest risk posed by climate change to both indoor and outdoor workers is heat, which can lead to heat-related illnesses like heat stroke and heat exhaustion. From 1992-2006, 423 worker deaths were attributed to heat exposure in the U.S. (PDF, 1.3 MB); a quarter of those hailed from the agriculture, forestry, fishing and hunting industries. Heat stress and fatigue can reduce alertness and work capacity, and lead to safety lapses that can increase the risk of injury. For workers who are paid based on output, it can also translate to longer hours or reduced daily income. It is estimated that five to 10 million American workers are exposed to outdoor heat beyond safe levels every year (PDF, 1.3 MB).

According to the National Climate Assessment, higher temperatures can also increase: 

  • Ground-level ozone (O3) and fine particulate matter air pollution, raising the risk of cardiopulmonary dysfunction, diminished lung function and respiratory illness. Chronic exposure (through inhalation or irritation of the nose, eyes, and throat) to elevated concentrations of ozone has been associated with permanent lung damage and increased risk of mortality from diseases such as pneumonia and chronic obstructive pulmonary disease (COPD). Ozone exposure among outdoor workers may also be associated with reduced productivity, as it “can increase the frequency of asthma attacks, cause shortness of breath, aggravate lung diseases, and cause permanent damage to lungs through long-term exposure.” Further, a 2011 study found that worker productivity increased when ozone concentrations decreased.
  • Carbon dioxide (CO2) levels in the air, which can promote the growth of plants that release airborne allergens. Higher pollen concentration and longer pollen seasons can increase allergies and asthma episodes. Short-term symptoms associated with allergens include coughing, wheezing, throat irritation, eye irritation, difficulty breathing and asthma attacks — any of which can limit worker productivity.

According to a 2014 report, the economic impacts of heat exposure on outdoor workers’ productivity could be dramatic, “particularly those working in construction, utility maintenance, landscaping and agriculture.” The report found that productivity for workers in those industries could be reduced by as much as 3% by the end of the century.” The famous “productivity slowdown” in the 1970s, authors say, saw labor productivity decline by half that much.

Chemical Combustion and Climate Change

Exposure to environmental chemicals is expected to significantly increase as a result of climate change. Polycyclic aromatic hydrocarbons (PAHs), which are formed during the combustion of carbon-containing materials such as petroleum-based fuels and biomass materials that include crops and forests, have been proven to be on the rise due to global warming. More than 15 of the 100 chemicals classified as PAHs are known to be mutagenic and carcinogenic, and increased exposure to them have been linked to cancer and ischemic heart disease. Hundreds of thousands of workers, particularly those working in trades or industries using or producing coal or coal products, are at the highest risk for PAH exposure. Those who work in close proximity to these types of combustion sources also include traffic police, tunnel construction workers, garage workers, taxi drivers and wildland firefighters.

An Increase in Pathogens and Infectious Diseases

Warmer average temperatures will mean longer warm seasons, earlier spring seasons, shorter and milder winters, and hotter summers — all of which are conditions that are more hospitable for many carriers of vector-borne diseases. According to the U.S. Global Change Research Program, “warm temperatures accelerate virtually all of the biological processes that affect transmission.” According to the World Health Organization, vector-borne diseases — transmitted by mosquitoes, ticks and fleas — account for more than 17 percent of all infectious diseases and cause more than 1 million deaths annually.

People who work closely with the natural environment, including soil, water, animals and infrastructure, will likely be at an increased risk of exposure to pathogenic microorganisms and infectious diseases. Some vector-borne diseases are more prevalent in certain regions than others; for instance, Lyme Disease tends to be more common in the Northeast and Upper Midwest. Conversely, outbreaks of mosquito-borne diseases such as West Nile Virus have occurred throughout the contiguous U.S. Research suggests, however, that many of these diseases — Rift Valley fever, yellow fever, malaria, dengue and chikungunya — will expand their geographical range as a result of changing weather and precipitation patterns. Disease transmission and infection could be of particular risk to animal agriculture and forestry workers, veterinarians, and those in meat-handling industries.  In extreme rain events, workers who operate and maintain septic systems or sewage systems, as those who work on plumbing and water systems could face increased exposure to human pathogens.

Workplace Violence

Global warming is expected to exacerbate conflict. Research shows that deviations from normal rainfall and moderate temperatures systematically increased conflict across major regions of the world through time. Additionally, multiple studies have found a compelling link between heat and crime. Heat has been tied to a higher likelihood that police officers will deploy deadly force and that individuals will exhibit aggressive or violent behavior, from relatively minor actions such as horn-honking, to violent crimes such as murder. Higher temperatures have also been linked to “increased retaliatory violence among groups.”

Why does heat contribute to higher rates of violence? Though researchers haven’t reached a definitive consensus on the answer to that question, some theorize that it could be the result of rational decision-making tactics on behalf of an individual—“weather factors into the probability of a crime without getting caught”—or that “temperature affects aggression levels…in a way that causes loss of control and heightened propensity to commit criminal acts.” This increase in conflict will increase the risk of injury and mortality for an array of occupations, including law enforcement, security personnel, armed forces, disaster response personnel, emergency medics, firefighters, and homeland security and border security personnel. 

Extreme Weather

Climate change is also creating extreme weather events. As wind patterns, temperature and levels of moisture are altered around the globe, more frequent and intense weather events and natural disasters — floods, landslides, storms, lightning, droughts and wildfires—take place. Workers responsible for rescue and cleanup of these events are exposed to conditions that could lead to traumatic injury.

Protecting Workers from Climate Change

It’s imperative that employers, safety professionals and workers stay informed about emerging issues and hazards associated with climate change as a way to address worker safety and health. Some strategies for protecting workers include:

  • Putting formal monitoring systems in place to limit worker exposures by altering workday schedules and/or increasing frequency and length of breaks.
  • Enhancing personal protective gear, as needed, and finding alternative for heat-inducing protective body gear.
  • Tracking changes in occupational exposures and patterns of injury and illness as they pertain to climate change.
  • Reinforcing protective practices with small, sensor-based technology that can pre-warn workers about exposures.
  • Training workers to identify climate-related exposures that can cause hazards.

These are actions that employers can take now to prepare for the inevitable exposures that will affect their vulnerable worker populations both now and in the years to come.

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