Both asbestos and smoking are among the most well-known causes of lung cancer, a particularly deadly form of cancer.

All cancer consists of cells that malfunction. More specifically, when a cell loses control over the mechanisms it uses to regulate its growth misfire, that cell can reproduce uncontrollably.

These cancer cells do not perform their usual function, they only reproduce. Cancer cells can spread and infiltrate other tissues, out-competing normal cells for nutrients, oxygen, and even space. Asbestosand smoking are among the known risk factors for cancer.

Smoking is a well-known risk factor for lung cancer. Smoking contains thousands of chemicals, including many known carcinogens. Carcinogens are chemicals that promote the formation of cancer cells. These chemicals often work by interfering with DNA, the chemical that controls cells. Damaging DNA can cause mutations, some of which can cause uncontrolled cellular growth or cancer.

On its own, asbestos can also promote asbestos lung cancer. Microscopic asbestos fibers can lodge themselves in the lung and damage lung tissue. Some types of asbestos are more strongly associated with lung cancer than other forms of asbestos, but all forms of the mineral carry some risk of asbestos lung cancer. All asbestos fibers are very difficult for the body to clear from the lungs, though again, the types more strongly linked to asbestos lung cancer and asbestosis are more difficult than others.

Combined, the effects of asbestos and smoking seem to have a synergistic effect. This means that the rate of cancer in smokers with asbestos exposure is even higher than the rate of cancer in smokers plus the rate of people with asbestos. The risk of asbestos lung cancer in smokers is greater than the sum of its parts.

Several mechanisms have been suggested for the relationship between asbestos and smoking. Asbestos fibers may damage lung tissue in a way that makes it easier for the carcinogens in tobacco smoke to get into tissue, or may tax the body’s repair systems, making it easier for cancer to get a foothold. While the mechanism is not proven, there is strong correlation between smoking and asbestos lung cancer.

Curiously, smoking seems to have almost no effect on another asbestos cancer, mesothelioma. Mesothelioma is sometimes mistakenly called asbestos lung cancer, since it has similar symptoms. However, mesothelioma starts in a different tissue that lines the chest instead of the lungs themselves.

Both asbestos lung cancer and mesothelioma have very poor outcomes, though some patients respond well to a grueling combination of invasive surgery, aggressive chemotherapy, and radiation therapy. Mesothelioma is almost exclusively linked to asbestos exposure. Asbestos and smoking can greatly increase the risk of asbestos lung cancer, but only asbestos seems to increase the risk of mesothelioma.

Asbestos was widely used in construction projects during the last 150 years or so. It is a naturally-occurring mineral, consisting of microscopic glass-like fibers. These fibers trap air, making it one of the best physical insulators in the world.

Additionally, the silica that comprises the fibers does not burn or melt easily, even under industrial conditions. These properties made the material extremely useful, but by the 1920s — at the latest — research had linked the material to various serious diseases.

Since many diseases linked to asbestos exposure take decades to fully manifest, patients are still developing diseases like asbestos lung cancer, mesothelioma, and asbestosis from asbestos exposures decades ago. In fact, asbestos lung cancer lawsuits are still being filed by individuals who worked in naval shipyards building ships and aircraft carriers that fought in World War II.