Just 4 percent of lung cancer deaths each year are caused by asbestos exposure, while the other 90 percent of lung cancer fatalities are the result of smoking.

While asbestos lung cancer is rare, nearly 5,000 people die from it each year.

Nearly everyone is exposed to asbestos at some point during their lives, but those at greatest risk of developing asbestos lung cancer are people exposed to it on a regular basis, such as through their job or by regular or substantial environmental contact.

First responders and recovery and cleanup personnel who worked at the World Trade Center — where asbestos was used to build the twin towers — following the 2001 terrorist attacks are at an increased risk of developing an asbestos-related disease, according to the National Cancer Institute.

Asbestos is a naturally occurring mineral and consists of threads of fiber that are resistant to heat, fire, and chemicals. Their durability resulted in asbestos being a staple in many commercial industries for generations.

Asbestos was used for strengthening cement and plastics, providing roofing insulation, fireproofing and soundproofing, as well as for the shipbuilding industry to insulate boilers, steam pipes, and hot water pipes.

Companies and manufacturers began mining and using asbestos in North America in the late 180os, according to asbestos.com, but over time it was learned that asbestos was a human carcinogen, causing such diseases as asbestos lung cancer.

“When someone disturbs an asbestos-containing product, they release the microscopic fibers into the air,” asbestos.com explains. “If inhaled, these thin fibers can become trapped in the lungs. Over long periods of time, they can accumulate and cause inflammation, scarring and other critical health problems. In some cases, the fibers can even trigger the development of lung cancer.”

In the late 1970s, the U.S. Consumer Product Safety Commission (CPSC) banned specific uses of asbestos because the asbestos fibers in products could be released into the environment during use. At the same time, manufacturers of electric hairdryers voluntarily agreed to stop using asbestos in their products.

In 1986, the Occupational Safety and Health Administration (OSHA) declared asbestos lung cancer as the greatest risk for Americans who worked with asbestos.

Three years later, the U.S. Environmental Protection Agency (EPA) banned all new uses of asbestos but permitted uses developed before 1989. The EPA also established regulations requiring school systems to inspect buildings for the presence of damaged asbestos and to eliminate or reduce asbestos exposure to occupants by removing the asbestos or encasing it.

In June 2000, U.S. manufacturers of crayons agreed to eliminate talc-containing asbestos from their products.

People in the United States are now less likely to have asbestos-related lung diseases because the mineral is no longer widely used.

Asbestos exposure results in lung cancer when the cancer forms in the lung tissue, usually in the cells lining the air passages. For people who suffer asbestosis – a chronic, progressive deterioration of the lungs caused by large amounts or long-term asbestos exposure punctuated by lung inflammation that results in shortness of breath, coughing, and permanent lung damage — cigarette smoking aggravates the condition.

The onset of asbestosis usually begins to 10 to 20 years after the initial exposure and becomes worse over time. The scarring of the lungs makes breathing more challenging due to the difficulty of oxygen and carbon monoxide to pass through the lungs and clear out the cancer-causing chemicals in cigarettes.

If you’ve been exposed to asbestos, let your doctor know. He or she can watch you for signs of asbestos-related problems and start treatment early, if needed. Early treatment may help prevent or delay complications.