The environment is filled with substances that can potentially lead to cancer in humans. Many people are familiar with some cancer-causing substances, which are broadly known as carcinogens.\nFor example, many homes install\u00a0radon\u00a0detectors to notify homeowners when harmful, cancer-causing radon gas seeps inside. But there are many more carcinogens present around us, and it\u2019s important to know where they can be and how we can limit our exposure.\nRemember, while some substances have been linked to cancer, exposure to them does not always lead to developing the disease. In addition to carcinogen exposure, a number of complex factors can lead to the development of cancer, including lifestyle and genetic makeup.\nExamples of Carcinogens in Nature\nArsenic\u00a0is a common cancer-causing substance found in the environment. It occurs naturally in air, water, and soil.\nPeople can be exposed to arsenic by drinking contaminated water or eating plants fed by contaminated water. Several types of cancer are associated with ingesting arsenic over extended periods of time.\nCertain substances found in plants have been associated with cancer when the plants or their products are ingested. Certain fungi found on plants like corn, peanuts, and tree nuts can contain\u00a0aflatoxins.\nPlants used for herbal medicines sometimes contain\u00a0aristolochic acids. Both of these substances have been linked to the development of cancer.\nOne of the most well-known cancer-causing agents in the environment is ultraviolet (UV) radiation from the sun. Exposure to the sun can cause skin cancer.\nExamples of Carcinogens in Building Materials\nExposure to\u00a0asbestos, which is found most often in the construction and shipbuilding industries, has been linked to lung cancer and mesothelioma, cancer of the chest and abdomen.\u00a0Wood dust\u00a0resulting from cutting wood using machines or tools has also been linked to cancer.\nPeople are exposed to\u00a0coal-tar products\u00a0when producing or using pavement tar, roofing tar, refractory bricks, or other coal-tar coatings. Coal-tar products are associated with an increased risk of cancer, particularly when they are absorbed through the skin, ingested, or inhaled.\nExamples of Carcinogens in Byproducts of Manufacturing\nThe manufacturing of many products results in the inhalation of fumes and other byproducts that may be high in carcinogens. Such cancer-causing substances include:\n\nBenzene\u2013 present in crude oil and frequently used in the chemical industry as a solvent or building block. Emitted from fires, including natural fires and burning cigarettes\nBeryllium\u2013 from the manufacture of products such as golf clubs, nuclear reactors, and aerospace components\nCadmium\u2013 from industries that use cadmium to produce other metals\nChromium\u2013 from industries such as stainless steel production, metal finishing, or welding\nFormaldehyde\u2013 from pressed woods during manufacture or subsequent use; also present in healthcare facilities and laboratories as disinfectant and preservative\nNickel\u2013 from metal-working industries (mining, welding, etc.)\nSoot(can contain organic carcinogens as well as arsenic, cadmium, chromium)\u2013 from heating, burning, or demolition of various organic materials\nVinyl Chloride\u2013 from the manufacture of vinyl products\n\nExamples of Carcinogens in Tobacco Smoke\nThere is a strong, well-documented association between smoking tobacco and the development of various types of cancer. Secondhand tobacco smoke,\u00a0which is produced by smokers and inhaled by those around them also can cause cancer.\nAccording to the National Cancer Institute, second-hand tobacco smoke contains more than 7,000 chemicals and at least 69 of them are carcinogens. Many of the harmful substances listed above are present in tobacco smoke, including\u00a0arsenic,\u00a0coal-tar products,\u00a0benzene,\u00a0cadmium,\u00a0nickel, and\nformaldehyde.\nThere is no safe level of exposure to cigarette smoke through direct inhalation or secondhand; people should definitely not smoke and should take care to avoid breathing the smoke of nearby tobacco smokers.\nAvoiding Cancer-Causing Substances\nThe United States has regulations in place to limit exposure to carcinogens in the workplace and elsewhere in the environment. The National Toxicology Program and the International Agency for Research on Cancer publish lists of known or suspected cancer-causing substances. Individuals can reference these lists to understand the risks associated with contact with certain carcinogens and limit their exposure.