Occupational cancer refers to cancers that arise, in whole or in part, from exposures to hazardous substances or conditions in the workplace. This form of cancer is a significant public health concern, impacting workers across various industries globally. Understanding its nature, causes, and prevention is important for safeguarding worker health.
Defining Occupational Cancer
Occupational cancer is defined as any cancer caused, either entirely or partially, by exposure to carcinogens or specific work-related circumstances. These carcinogens are agents, mixtures, or situations that can cause cancer or increase the risk of developing it. The unique aspect of occupational cancer is its direct link to the work environment, distinguishing it from other cancer types.
A significant challenge in identifying occupational cancer is the long latency period, which is the time between initial exposure to a carcinogen and the diagnosis of cancer. This period can range from 5 years to over 40 years, making it difficult to connect a specific cancer diagnosis to past workplace exposures. For example, mesothelioma, a cancer strongly linked to asbestos, rarely appears less than 10 years after first exposure and can manifest even after 40 years.
Key Causes and Exposures
Occupational cancers result from exposure to various agents in the workplace, broadly categorized as chemical and physical carcinogens. Chemical agents are substances that can damage DNA and cellular processes, leading to uncontrolled cell growth. Physical agents involve forms of energy that can also induce cancerous changes.
Common chemical carcinogens include asbestos, a naturally occurring mineral fiber once widely used in construction and manufacturing. Inhaling asbestos fibers can lead to cancer decades after exposure. Benzene, an organic solvent used in industries like rubber manufacturing and chemical production, is another established carcinogen. Chromium compounds, particularly hexavalent chromium, and nickel compounds are also recognized as cancer-causing agents found in various industrial processes. Other chemical exposures include formaldehyde, often used in resins and embalming, and aromatic amines, found in dyes and rubber manufacturing.
Physical agents that can cause occupational cancer include different forms of radiation. Ionizing radiation, such as X-rays, can damage cellular DNA and increase cancer risk. Ultraviolet (UV) radiation, primarily from sunlight, is a known cause of skin cancer for outdoor workers. The duration and intensity of exposure to these agents are directly related to the risk of developing cancer, meaning longer or higher-level exposures generally increase the likelihood of disease.
Common Cancers Linked to Occupation
Specific types of cancer are frequently associated with particular occupational exposures. Lung cancer is a common occupational cancer, often linked to exposure to asbestos, crystalline silica, diesel engine exhaust, and certain metal fumes like chromium and nickel compounds. Workers in construction, mining, and painting are frequently at risk due to these exposures.
Mesothelioma, a rare but aggressive cancer of the lining of the lungs or abdomen, is almost exclusively caused by asbestos exposure. Bladder cancer is another work-related cancer, with a significant portion of cases linked to prolonged contact with industrial chemicals such as aromatic amines, polycyclic aromatic hydrocarbons (PAHs), and diesel exhaust. Industries like dye, rubber, and textile manufacturing, as well as painting and printing, have higher rates of occupational bladder cancer.
Leukemia, a cancer of the blood-forming cells, has associations with workplace exposure to benzene, formaldehyde, and ionizing radiation. Workers in chemical plants, printing, and those exposed to certain pesticides may face increased risks. Nasal and sinus cancers are linked to exposures to wood dust, leather dust, nickel compounds, and formaldehyde, often seen in furniture making and textile industries. Skin cancer, particularly non-melanoma types, can result from prolonged outdoor work due to UV radiation exposure, or contact with substances like coal tars, pitches, and mineral oils.
Identifying and Preventing Occupational Cancer
Identifying occupational cancer can be challenging due to its long latency period and the influence of multiple factors in cancer development. A detailed occupational history, documenting past and present job roles and exposures, is important for connecting a cancer diagnosis to potential workplace hazards.
Medical surveillance programs, which involve ongoing health checks, also play a role in early detection of work-related illnesses. These programs aim to identify early signs of health effects, allowing for timely intervention and adjustments to workplace controls.
Preventing occupational cancer primarily involves controlling exposure to carcinogens in the workplace. The hierarchy of controls outlines a systematic approach to risk management, prioritizing methods from most to least effective:
- Elimination: The most effective measure, which means physically removing the hazard from the workplace, such as discontinuing the use of a hazardous material.
- Substitution: If elimination is not possible, involves replacing a hazardous material or process with a safer alternative.
- Engineering controls: Next in the hierarchy, these involve isolating workers from hazards through design modifications, like installing ventilation systems or machine guards.
- Administrative controls: Following these, they change the way work is performed to reduce exposure, such as implementing job rotation schedules or limiting time in hazardous areas.
- Personal protective equipment (PPE): Finally, such as respirators, gloves, and protective clothing, provides a barrier between the worker and the hazard. PPE is considered the least effective control method and should be used in conjunction with other controls.
Employers have a responsibility to provide a safe work environment and proper training, while employees also play a part in adhering to safety procedures and using provided protections.