Every year, people in the United States become ill as a result of occupational hazards. Workers exposed to asbestos can develop cancer. Coal miners can get black lung disease. Some of these diseases can be fatal, even when properly treated. 24/7 Wall St. identified some of the most common jobs that have a high risk of sickness, and the diseases and ailments associated with them.

MORTICIANSRisk: Leukemia
Perceived cause: Formaldehyde
Median annual wage: $52,210

Morticians who use formaldehyde to embalm bodies are at an exceptionally high risk of leukemia. "Previous studies have shown excess mortality from lymphohematopoietic malignancies and brain cancer in anatomists, pathologists, and funeral industry workers, all of whom may have worked with formaldehyde," reports the Journal of the National Cancer Institute. Formaldehyde, which is used in plywood manufacturing as well as embalming, was only officially classified as a carcinogen this past June.

PIPEFITTERSRisk: Mesothelioma
Perceived cause: Asbestos
Median annual wage: $46,660

Malignant mesothelioma is a life-threatening type of cancer commonly caused by exposure to asbestos. Asbestos use peaked in 1973 in the U.S. ,but its use and has since declined by 99.8%, according to the American Lung Association. Because Mesothelioma can take 20 to 40 years to develop, it has only been in recent years that the disease has become extremely widespread. Some occupations, such as pipefitters, still put workers at risk of exposure. One Massachusetts developer was recently fined for neglecting to take precautions to ensure that workers would protected from airborne asbestos while removing pipes lined with the fiber. Other occupations that have seen highest rates of the illness are plumbers, mechanical engineers, electricians, and elementary school teachers who spent years in older buildings.

CONCRETE MIXERSRisk: Silicosis
Perceived cause: Silica
Median annual wage: $43,850

Silicosis is a disabling respiratory disease caused by inhaling silica dust, which is used in the production of glass products, optical fibers, cement, and more. The disease can lead to “extreme shortness of breath, loss of appetite, chest pains, and respiratory failure, which can cause death,” reports the American Lung Association. More than one million workers are exposed to silica each year. The highest rate of silicosis deaths occur among so-called non-construction laborers and mining machine operators.

PILOTSRisk: Melanoma
Perceived cause: Intense exposure to sunlight
Median annual wage: $103,210

Melanoma is the most dangerous type of skin cancer and is related to sunlight exposure. Studies have shown that brief periods of high intensity exposure are more risky than long-term, lower intensity exposure, according to a report out of the UK on occupational mortality. The report shows that aircraft flight deck officers, including pilots, have an exceptionally high mortality rate from melanoma. The study notes that in addition to solar radiation, cosmic radiation exposure could be a contributing factor. A different study, conducted by Iceland’s University of Reykjavik, reports that airline pilots have up to 25 times the average rate of melanoma.

FIREFIGHTERSRisk: Heart attack
Perceived cause: Physical and psychological stress, exposure to toxic elements
Median annual wage: $45,520

It is not fire or smoke inhalation that is the number one irregular cause of death among firefighters, but heart attacks. When fighting a fire, the chance that a firefighter will have a heart attack increases up to 100 times the normal rate. Even when they aren’t fighting fires, firefighters are at a higher risk of heart attack, a report from Harvard School of Public Health shows. Risk of heart attack is increased for firefighters when they respond to an alarm, return from an incident, or engage in physical activity, including training. The occupation of firefighter, by nature, entails dealing with extreme heat, exposure to toxic substances, and causes high levels of psychological and physiological stress.

COAL MINERSRisk: Pneumoconiosis
Perceived cause: Coal dust
Median annual wage: $43,010

Coal miners far and away have the highest mortality rate from pneumoconiosis, or black lung disease, which is cause by long-term exposure to coal dust. According to the National Institutes of Health, one’s “risk of getting coal worker's pneumoconiosis depends on how long [they] have been around coal dust.” The Centers for Disease Control and Prevention report that between 1968 and 2006, coal worker’s pneumoconiosis was the cause of death for 28,912 people aged 25 and older.

WELDERSRisk: Manganism
Perceived cause: Manganese
Median annual wage: $35,450

The fumes produced by welding metal often contain small amounts of manganese. Prolonged exposure to these fumes can lead to a “Parkinsonian syndrome” called manganism. According to the Centers for Disease Control and Prevention, symptoms “may include tremors, slowness of movement, muscle rigidity, and poor balance.” The disease can also occur in those who work around “dry-cell batteries, anti-knock gasoline additives, pesticides, pigments, dyes, inks and incendiary devices.”