Melanoma is a type of skin cancer that occurs when the pigment-producing cells in the skin called melanocytes become malignant. It is the deadliest type of skin cancer and can spread to other parts of the body if not treated early.

According to the American Cancer Society, there will be an estimated 105,380 new cases of melanoma in the United States in 2020, and about 6,850 people will die from the disease. While exposure to UV radiation from the sun and tanning beds is a major risk factor for melanoma, occupational exposure to certain chemicals and substances has also been linked to an increased risk of developing the disease.

Asbestos

Asbestos is a group of six naturally occurring minerals that have been used for their heat-resistant properties in many industrial and construction applications, such as insulation, roofing, and brake pads.

When asbestos fibers are inhaled or ingested, they can cause mesothelioma, lung cancer, and other respiratory diseases. Epidemiological studies have also found a positive association between asbestos exposure and melanoma.

A study of 955 Italian asbestos workers found that the standardized incidence ratio (SIR) for melanoma was 2.28, meaning that the workers had a 128% higher risk of developing melanoma than the general population. Another study of 17,845 Swedish construction workers found that the SIR for melanoma was 1.55 among asbestos-exposed workers and 1.24 among non-asbestos-exposed workers, indicating a dose-response relationship.

Polycyclic aromatic hydrocarbons (PAHs)

PAHs are a group of chemicals that are formed during incomplete combustion of organic matter, such as coal, oil, and tobacco. They are also found in grilled and charred meat and fish, cigarette smoke, and diesel exhaust.

PAHs are known to be carcinogenic and have been linked to lung cancer, bladder cancer, and other cancers. Some studies have suggested that PAHs may also play a role in the development of melanoma.

For example, a case-control study of 250 melanoma patients and 504 controls in Italy found that high levels of PAH-DNA adducts, which are biomarkers of PAH exposure, were associated with a significantly increased risk of melanoma (odds ratio of 2.5 for the highest tertile compared with the lowest tertile).

Solar radiation

Exposure to solar radiation, especially UV radiation, is the most well-established risk factor for melanoma. Occupations that involve outdoor work, such as farming, construction, and lifeguarding, have been associated with an increased risk of melanoma.

A meta-analysis of 51 studies found that the overall relative risk of melanoma for outdoor workers was 1.31, meaning that they had a 31% higher risk of developing melanoma than indoor workers. The risk was higher for those with a longer duration of outdoor work, older age, and fair skin. Solar radiation can also interact with other occupational carcinogens, such as arsenic and coal tar, to increase the risk of melanoma.

Ionizing radiation

Ionizing radiation is a type of high-energy radiation that can penetrate the body and damage DNA, leading to the development of cancer. It is used in medical imaging, such as X-rays and CT scans, as well as in nuclear power plants and radiation therapy.

Epidemiological studies have suggested a positive association between ionizing radiation and melanoma, although the evidence is limited and conflicting. A study of 3,000 Russian Chernobyl liquidators, who were exposed to ionizing radiation after the nuclear disaster in 1986, found a significantly increased risk of melanoma compared with the general population (odds ratio of 1.69).

Another study of 60,276 US radiologic technologists found no significant association between occupational radiation exposure and melanoma after adjusting for other risk factors.

Arsenic

Arsenic is a metalloid that is naturally occurring in soil and water and is also used in some industrial processes, such as wood preservation, glass production, and semiconductor manufacturing.

Chronic exposure to arsenic, usually through contaminated drinking water, can cause skin lesions and cancer, including melanoma. Arsenic can also interact with UV radiation to increase the risk of melanoma.

A study of 11,365 Chinese tin miners who were exposed to both arsenic and UV radiation found a significantly higher incidence of melanoma compared with the general population (SIR of 9.8).

Other occupational risk factors

Other occupational risk factors that have been suggested to increase the risk of melanoma include:.

Coal tar and pitch, which are used in the production of roofing materials, asphalt, and aluminum smelting, have been classified by the International Agency for Research on Cancer (IARC) as probably carcinogenic to humans and have been linked to an increased risk of skin cancer, including melanoma.
Hydroquinone, a skin-lightening agent that is used in the production of photographic film and as a hair dye, has been shown to increase the risk of skin cancer in animal studies, although the evidence in humans is limited.
Chlorinated solvents, such as trichloroethylene and tetrachloroethylene, which are used as degreasers and dry-cleaning agents, have been linked to an increased risk of non-Hodgkin lymphoma, but their effect on melanoma is unclear.

Conclusion

Occupational exposure to certain chemicals and substances can increase the risk of melanoma, a deadly type of skin cancer.

While exposure to solar radiation is the most well-established risk factor for melanoma, other factors such as asbestos, polycyclic aromatic hydrocarbons, ionizing radiation, and arsenic can also contribute to the development of the disease. It is important for workers who are exposed to these carcinogens to be aware of the risks and to take appropriate measures to protect themselves, such as wearing protective clothing and using sunscreen.

Employers should also provide training and safety equipment to minimize exposure to these occupational hazards.