Does any exposure to a known carcinogen always result in cancer?

Any substance that causes cancer is known as a carcinogen. But simply because a substance has been designated as a carcinogen does not mean that the substance will necessarily cause cancer. Many factors influence whether a person exposed to a carcinogen will develop cancer, including the amount and duration of the exposure and the individual’s genetic background. Cancers caused by involuntary exposures to environmental carcinogens are most likely to occur in subgroups of the population, such as workers in certain industries who may be exposed to carcinogens on the job.

How can exposures to carcinogens be limited?

In the United States, regulations have been put in place to reduce exposures to known carcinogens in the workplace. Outside of the workplace, people can also take steps to limit their exposure to known carcinogens, such as testing their basement for radon, quitting smoking, limiting sun exposure, or maintaining a healthy weight.

How many cancers are caused by involuntary exposure to carcinogens in the environment?

This question cannot be answered with certainty because the precise causes of most cancers are not known. Some researchers have suggested that, in most populations, environmental exposures are responsible for a relatively small proportion of total cancers (less than 4 percent), whereas other researchers attribute a higher proportion (19 percent) to environmental exposures.

Who decides which environmental exposures cause cancer in humans?

Two organizations—the National Toxicology Program (NTP), an interagency program of the U.S. Department of Health and Human Services (HHS), and the International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization—have developed lists of substances that, based on the available scientific evidence, are known or are reasonably anticipated to be human carcinogens.

Specifically, the NTP publishes the Report on Carcinogens every few years. This congressionally mandated publication identifies agents, substances, mixtures, or exposures (collectively called “substances”) in the environment that may cause cancer in humans. The 2014 edition lists 56 known human carcinogens and includes descriptions of the process for preparing the science-based report and the criteria used to list a substance as a carcinogen.

IARC also produces science-based reports on substances that can increase the risk of cancer in humans. Since 1971, the agency has evaluated more than 900 agents, including chemicals, complex mixtures, occupational exposures, physical agents, biological agents, and lifestyle factors. Of these, more than 400 have been identified as carcinogenic, probably carcinogenic, or possibly carcinogenic to humans.

How does the NTP decide whether to include a substance on its list of known human carcinogens?

As new potential carcinogens are identified, they are evaluated scientifically by the NTP’s Board of Scientific Counselors and the NTP Director. Next, a draft Report on Carcinogens monograph is prepared, which is reviewed by other scientific experts as needed, the public, and other federal agencies. The draft monograph is then revised as necessary and released for additional public comment and peer review by a dedicated panel of experts. Lastly, a finalized monograph and recommendation for listing is sent to the HHS Secretary for approval.

What are aflatoxins?

Aflatoxins are a family of toxins produced by certain fungi that are found on agricultural crops such as maize (corn), peanuts, cottonseed, and tree nuts. The main fungi that produce aflatoxins are Aspergillus flavus and Aspergillus parasiticus, which are abundant in warm and humid regions of the world. Aflatoxin-producing fungi can contaminate crops in the field, at harvest, and during storage.

How are people exposed to aflatoxins?

People can be exposed to aflatoxins by eating contaminated plant products (such as peanuts) or by consuming meat or dairy products from animals that ate contaminated feed. Farmers and other agricultural workers may be exposed by inhaling dust generated during the handling and processing of contaminated crops and feeds.

Which cancers are associated with exposure to aflatoxins?

Exposure to aflatoxins is associated with an increased risk of liver cancer.

How can aflatoxin exposure be reduced?

You can reduce your aflatoxin exposure by buying only major commercial brands of nuts and nut butters and by discarding nuts that look moldy, discolored, or shriveled. To help minimize risk, the U.S. Food and Drug Administration (FDA) tests foods that may contain aflatoxins, such as peanuts and peanut butter. To date, no outbreak of human illness caused by aflatoxins has been reported in the United States, but such outbreaks have occurred in some developing countries.

What are aristolochic acids?

Aristolochic acids are a group of acids found naturally in many types of plants known as Aristolochia (birthworts or pipevines) and some types of plants known as Asarum (wild ginger), which grow worldwide.

How are aristolochic acids used?

Plants containing aristolochic acids are used in some herbal products intended to treat a variety of symptoms and diseases, such as arthritis, gout, and inflammation. These products have not been approved by the U.S. Food and Drug Administration (FDA) and are often marketed as dietary supplements or “traditional medicines.”

How are people exposed to aristolochic acids?

Exposure may occur through intentionally or unknowingly eating or drinking herbal or food products that contain aristolochic acids.

Which cancers are associated with exposure to aristolochic acids?

Cancers of the upper urinary tract (renal pelvis and ureter) and bladder have been reported among individuals who had kidney damage caused by the consumption of herbal products containing aristolochic acids.

How can exposures be reduced?

To reduce your risk, do not use herbal products that contain aristolochic acids. The FDA provides a list of some products containing aristolochic acids.

​​​​​​What is Arsenic?

Arsenic is a naturally occurring substance that can be found in air, water, and soil. It can also be released into the environment by certain agricultural and industrial processes, such as mining and metal smelting. Arsenic comes in two forms (organic and inorganic); the inorganic form is more toxic than the organic form.

How are people exposed to arsenic?

People in the general population may be exposed to arsenic by smoking tobacco, being around tobacco smoke, drinking contaminated water, or eating food from plants that were irrigated with contaminated water. Inorganic arsenic is naturally present at high levels in the groundwater of certain countries, including the United States. Exposure to arsenic in contaminated drinking water is generally thought to be more harmful to human health than exposure to arsenic in contaminated foods.

In the past, people were exposed to arsenic during certain medical treatments and through contact with pesticides. Inorganic arsenic compounds were widely used as pesticides until the mid-1900s and were found in some medicines until the 1970s. In the 1990s, research showed that an arsenic compound, arsenic trioxide, was effective in the treatment of acute promyelocytic leukemia.

Inorganic arsenic is naturally present at high levels in the groundwater of certain countries, including the United States.

Which cancers are associated with exposure to arsenic?

Prolonged ingestion of arsenic-containing drinking water is associated with an increased risk of bladder cancer and skin cancer, and medical exposure to arsenic has been clearly associated with skin cancer in epidemiological studies. In addition, cancers of the lung, digestive tract, liver, kidney, and lymphatic and hematopoietic systems have been linked to arsenic exposure.

How can exposures be reduced?

Access to a safe water supply for drinking, food preparation, and irrigation of food crops is the most important way to prevent exposures to arsenic.

​​​​​​What is asbestos?

Asbestos is the name given to a group of naturally occurring fibrous minerals that are resistant to heat and corrosion. Because of these properties, asbestos has been used in commercial products such as insulation and fireproofing materials, automotive brakes, and wallboard materials.

How are people exposed to asbestos?

If products containing asbestos are disturbed, tiny asbestos fibers are released into the air. When asbestos fibers are breathed in, they may get trapped in the lungs and remain there for a long time. Over time, accumulated asbestos fibers can cause tissue inflammation and scarring, which can affect breathing and lead to serious health problems.

Low levels of asbestos fibers are present in the air, water, and soil. Most people, however, do not become ill from this type of exposure. People who become ill from asbestos usually have been exposed to it on a regular basis, most often in a job where they have worked directly with the material or through substantial environmental contact.

Most heavy exposures to asbestos occurred in the past. The heaviest exposures today tend to occur in the construction industry and in ship repair, particularly during the removal of asbestos-containing materials due to renovation, repairs, or demolition. Workers may also be exposed during the manufacture of asbestos-containing products, such as textiles, friction products, insulation, and other building materials.

A garage built with asbestos-containing material

Which cancers are associated with exposure to asbestos?

Exposure to asbestos causes mesothelioma (a cancer of the thin membranes that line the chest and abdomen) and cancers of the lung, larynx, and ovary. Mesothelioma is the most common form of cancer associated with asbestos exposure, although the disease is relatively rare.

What can be done to reduce the hazards of asbestos?

The use of asbestos is now highly regulated in the United States. The Occupational Safety and Health Administration has issued standards for the construction industry, general industry, and shipyard employment sectors.

How does smoking tobacco affect the risk of asbestos-associated cancers?

Many studies have shown that the combination of tobacco smoking and asbestos exposure is particularly hazardous. However, there is also evidence that quitting smoking reduces the risk of lung cancer among asbestos-exposed workers.

​​​​​​What is benzene?

Benzene is a colorless or light-yellow liquid chemical at room temperature. It is used primarily as a solvent in the chemical and pharmaceutical industries, as a starting material and an intermediate in the synthesis of numerous chemicals, and in gasoline. Benzene is produced by both natural and man-made processes. It is a natural component of crude oil, which is the main source of benzene produced today. Other natural sources include gas emissions from volcanoes and forest fires.

How are people exposed to benzene?

People are exposed to benzene primarily by breathing air that contains the chemical. Workers in industries that produce or use benzene may be exposed to the highest levels of the chemical, although federal and state regulations have reduced these exposures in recent decades. Similarly, limits on the amount of benzene allowed in gasoline have contributed to reduced exposures.

Mainstream cigarette smoke is another source of benzene exposure, accounting for about half of the total U.S. population exposure to this chemical. Among smokers, 90 percent of benzene exposures come from smoking. Benzene may also be found in glues, adhesives, cleaning products, and paint strippers. Outdoor air contains low levels of benzene from secondhand tobacco smoke, gasoline fumes, motor vehicle exhaust, and industrial emissions.

Outdoor air contains low levels of benzene from gasoline fumes, secondhand smoke, and other sources.

Which cancers are associated with exposure to benzene?

Exposure to benzene may increase the risk of developing leukemia and other blood disorders.

How can exposure be reduced?

Don’t smoke and avoid exposure to secondhand tobacco smoke. Try to limit exposure to gasoline fumes. For workers who may be exposed to benzene on the job, the U.S. Centers for Disease Control and Prevention has information about how you can protect yourself and what to do if you are exposed.

​​​​​​What is benzidine?

Benzidine is a manufactured chemical that does not occur in nature. In the past, large amounts of benzidine were used to produce dyes for cloth, paper, and leather. It was also used in clinical laboratories for detecting blood, as a rubber-compounding agent, and in the manufacture of plastic films. However, benzidine has not been sold in the United States since the mid-1970s, and it is no longer used in medical laboratories or in the rubber and plastics industries.

Model of the benzidine molecule

How are people exposed to benzidine?

Inhalation and accidental ingestion are the main ways people can be exposed to benzidine-based dyes in the United States. As benzidine-based dyes were removed from both industrial and consumer markets and replaced with other types of dyes, the potential for exposure has declined.

Which cancers are associated with exposure to benzidine?

Occupational exposure to benzidine results in an increased risk of bladder cancer, according to studies of workers in different geographic locations.

​​​​​​What is beryllium?

Beryllium is a metal that is found in nature, especially in beryl and bertrandite rock. It is extremely lightweight and hard, is a good conductor of electricity and heat, and is non-magnetic. Because of these properties, beryllium is used in high-technology consumer and commercial products, including aerospace components, transistors, nuclear reactors, and golf clubs.

Coal-fired power plants are a major source of beryllium-containing particles.

How are people exposed to beryllium?

Most exposures to beryllium that cause disease are related to beryllium processing. The major route of human exposure is through airborne particles of beryllium metal, alloys, oxides, and ceramics. Beryllium particles are inhaled into the lungs and upper respiratory tract. Hand-to-mouth exposures and skin contact with ultrafine particles can also occur.

Although beryllium occurs in nature, the major source of its emission into the environment is through the combustion of fossil fuels (primarily coal), which releases beryllium-containing particulates and fly ash into the atmosphere.

Which cancers are associated with exposure to beryllium?

An increased risk of lung cancer has been observed in workers exposed to beryllium or beryllium compounds.

​​​​​​What is 1,3-butadiene?

1,3-Butadiene is a colorless gas at room temperature with a gasoline-like odor. It is used to produce synthetic rubber products, such as tires, resins, and plastics, and other chemicals.

How are people exposed to 1,3-butadiene?

Exposure to 1,3-butadiene mainly occurs among workers who breath contaminated air on the job. Other sources of exposure include automobile exhaust; tobacco smoke; and polluted air and water near chemical, plastic, or rubber facilities.

1,3-Butadiene is used to produce synthetic rubber products, such as tires.

Which cancers are associated with exposure to 1,3-butadiene?

Studies have consistently shown an association between occupational exposure to 1,3-butadiene and an increased incidence of leukemia.

How can exposures be reduced?

The U.S. Occupational Safety & Health Administration has information on exposure limits for 1,3-butadiene. People can also reduce their exposure to 1,3-butadiene by avoiding tobacco smoke.

What is cadmium?

Cadmium is a natural element found in tiny amounts in air, water, soil, and food. All soils and rocks, including coal and mineral fertilizers, contain some cadmium. Most cadmium used in the United States is extracted during the production of other metals such as zinc, lead, and copper. Cadmium does not corrode easily and has been used to manufacture batteries, pigments, metal coatings, and plastics.

Cadmium is a natural element found in the earth's crust, and has been used to make batteries and other products.

How are people exposed to cadmium?

Exposure to cadmium occurs mostly in workplaces where cadmium products are made. The major routes of occupational exposure are inhalation of dust and fumes and incidental ingestion of dust from contaminated hands, cigarettes, or food.

The general population is exposed to cadmium by breathing tobacco smoke or eating cadmium-contaminated foods, which is the major source of cadmium exposure for nonsmokers. The expanding nickel–cadmium (NiCd) battery recycling industry is also a potential source for exposure.

Which cancers are associated with exposure to cadmium?

Occupational exposure to various cadmium compounds is associated with an increased risk of lung cancer.

How can exposures be reduced?

Dispose of nickel–cadmium batteries properly, and do not allow children to play with these batteries. Avoid tobacco smoke. If you work with cadmium, use all recommended safety precautions to avoid carrying cadmium-containing dust home from work on your clothing, skin, hair, or tools. The U.S. Occupational Safety & Health Administration has more information about controlling exposures to cadmium.

What is coal tar?

Coal tar is derived from coal. It is a byproduct of the production of coke, a solid fuel that contains mostly carbon, and coal gas. Coal tar is used primarily for the production of refined chemicals and coal-tar products, such as creosote and coal-tar pitch. Certain preparations of coal tar have long been used to treat various skin conditions, such as eczema, psoriasis, and dandruff.

What is coal-tar pitch?

Coal-tar pitch is a thick black liquid that remains after the distillation of coal tar. It is used as a base for coatings and paint, in roofing and paving, and as a binder in asphalt products. Both coal tar and coal-tar pitch contain many chemical compounds, including carcinogens such as benzene.

Coal-tar pitch is found in some types of asphalt and other coal-tar products.

How are people exposed to coal tar and coal-tar pitch?

The primary routes of human exposure to coal tars and coal-tar products are inhalation, ingestion, and absorption through the skin. Exposure to coal tars and coal-tar pitches may occur at foundries and during coke production, coal gasification, and aluminum production. Other workers who may be exposed to coal-tar pitches include those who produce or use pavement tar, roofing tar, coal-tar paints, coal-tar enamels, other coal-tar coatings, or refractory bricks.

The general population may be exposed to coal tars in environmental contaminants and through the use of coal tar preparations to treat skin disorders such as eczema, psoriasis, and dandruff.

Which cancers are associated with exposure to coal tar and coal-tar pitch?

Occupational exposure to coal tar or coal-tar pitch increases the risk of skin cancer. Other types of cancer, including lung, bladder, kidney, and digestive tract cancer, have also been linked to occupational exposure to coal tar and coal-tar pitch.

How can exposures be reduced?

Exposures to coal tar and coal-tart pitch are regulated under the U.S. Occupational Safety and Health Administration’s (OSHA) Air Contaminants Standard for general industry, shipyard employment, and the construction industry. OSHA provides detailed safety and health information about coal-tar pitch to the public.

What are coke oven emissions?

Coke oven emissions come from large ovens that are used to heat coal to produce coke, which is used to manufacture iron and steel. The emissions are complex mixtures of dust, vapors, and gases that typically include carcinogens such as cadmium and arsenic. Chemicals recovered from coke oven emissions are used as raw materials for producing items such as plastics, solvents, dyes, paints, and insulation.

Emissions from coking plants typically include carcinogens such as cadmium and arsenic.

How are people exposed to coke oven emissions?

Workers at coking plants and coal-tar production plants may be exposed to coke oven emissions. Occupational exposures can also occur among workers in the aluminum, steel, graphite, electrical, and construction industries. The primary routes of potential human exposure to coke oven emissions are inhalation and absorption through the skin.

Which cancers are associated with exposure to coke oven emissions?

Exposure to coke oven emissions increases the risk of lung cancer and, possibly, kidney cancer.

How can exposures be reduced?

The U.S. Occupational Safety & Health Administration provides information about exposure limits for coke oven emissions.

​​​​​​What is chromium and what are hexavalent chromium compounds?

Chromium is an odorless and tasteless metallic element that is found in the earth’s crust. It is also found in air, water, soil, and food.

Hexavalent chromium compounds are a group of chemicals that have useful properties, such as corrosion resistance, durability, and hardness. These compounds have been used widely as corrosion inhibitors and in the manufacture of pigments, metal finishing and chrome plating, stainless steel production, leather tanning, and wood preservatives. They have also been used in textile-dyeing processes, printing inks, drilling muds, fireworks, water treatment, and chemical synthesis.

Hexavalent chromium compounds are used widely in metal finishing and chrome plating, stainless steel production, leather tanning, and wood preservatives.

How are people exposed to hexavalent chromium compounds?

Occupational exposure to hexavalent chromium can occur from inhalation of dusts, mists, or fumes containing hexavalent chromium, or from eye or skin contact. Industries with the largest number of workers exposed to high concentrations of airborne hexavalent chromium compounds include electroplating, welding, and chromate painting.

Which cancers are associated with exposure to hexavalent chromium compounds?

Occupational exposure to these compounds is associated with increased risks of lung cancer and cancer of the paranasal sinuses and nasal cavity.

How can exposures be reduced?

The U.S. Occupational Safety & Health Administration has exposure limits and information about analytical methods used to evaluate hexavalent chromium exposure.

​​​​​​What is crystalline silica?

An abundant natural material, crystalline silica is found in stone, soil, and sand. It is also found in concrete, brick, mortar, and other construction materials. Crystalline silica comes in several forms, with quartz being the most common. Quartz dust is respirable crystalline silica, which means it can be taken in by breathing.

How are people exposed to crystalline silica?

Exposure to tiny particles of airborne silica, primarily quartz dust, occurs mainly in industrial and occupational settings. For example, workers who use handheld masonry saws to cut materials such as concrete and brick may be exposed to airborne silica. When inhaled, these particles can penetrate deep into the lungs.

The primary route of exposure for the general population is inhaling airborne silica while using commercial products containing quartz. These products include cleansers, cosmetics, art clays and glazes, pet litter, talcum powder, caulk, and paint.

Which cancers are associated with exposure to crystalline silica?

Exposure of workers to respirable crystalline silica is associated with elevated rates of lung cancer. The strongest link between human lung cancer and exposure to respirable crystalline silica has been seen in studies of quarry and granite workers and workers involved in ceramic, pottery, refractory brick, and certain earth industries.

Dioxins are mainly byproducts of industrial practices. They are produced through a variety of incineration processes, including improper municipal waste incineration and burning of trash, and can be released into the air during natural processes, such as forest fires and volcanoes. Almost every living creature has been exposed to dioxins or dioxin-like compounds (DLCs).

Strict regulatory controls on major industrial sources of dioxin have reduced emissions into the air by 90 percent, compared to levels in 1987.

Today people are exposed to dioxins primarily by eating food, in particular animal products, contaminated by these chemicals. Dioxins are absorbed and stored in fat tissue and, therefore, accumulate in the food chain. More than 90 percent of human exposure is through food.

Before safeguards and regulations were introduced, dioxin releases were a major problem in the United States. The Polychlorinated Biphenyls (PCBs) worked with industry to ban products containing dioxin and to curb dioxin emissions. In 1979, the EPA banned the manufacture of products containing Polychlorinated Biphenyls (PCBs) some of which are included under the term dioxin.

Consumers should eat a balanced diet and follow the 2010 Dietary Guidelines for Americans. Each food group provides important nutrients needed for health.

The following steps can reduce the potential for exposure to dioxin:

• Remove skin from fish and chicken
• Select cuts of meat that are naturally lean, or trim visible fat
• When catching your own fish, check local fishing advisories, as there may be consumption limits for particular kinds of fish, in particular bodies of water where local contamination has occurred
• Use fat-free or low-fat milk and use butter in moderation

However, dioxins break down very slowly and emissions released long ago remain in the environment. Some dioxins endure a long time, are extremely resistant to environmental degradation, and therefore are classified as persistent organic pollutants (POPs). Dioxin contamination is an increasing problem in some developing countries, particularly with uncontrolled burning, and dismantling and recycling of electronic products, such as computers.

Health Effects

The dioxin TCDD, or Mutagen: Talking Glossary of Genetic Terms, is a known cancer-causing agent, and other DLCs are known to cause cancer in laboratory animals. Additionally, dioxin exposure has been linked to a number of other diseases, including type 2 diabetes, ischemic heart disease, and an acne-like skin disease called chloracne, a hallmark of dioxin exposure.

Dioxins can cause developmental problems in children, lead to reproductive and infertility problems in adults, result in miscarriages, damage the immune system, and interfere with hormones.

Exposure to dioxins has widespread effects in nearly every vertebrate species, at nearly every stage of development, including in the womb.

The Science of Dioxins

Dioxins are a family of compounds that share distinct chemical structures and characteristics. Numerous dioxin-like compounds have been identified that are considered to have significant toxicity and can cause disease. The singular term dioxin refers to the most toxic compound, TCDD.

NIEHS researchers continue to explore the detailed chemical pathway through which dioxin damages the body, but scientists are now confident that the first step takes place when dioxin binds to an intracellular protein known as the aryl hydrocarbon receptor (AhR). When that happens, the AhR can alter the expression, or function, of certain genes. The resulting cellular imbalance leads to a disruption in normal cell function and ultimately adverse health effects.

In addition to TCDD, many other chemicals bind to AhR. About 400 compounds in the environment act on the body through the AhR receptor. Public health officials around the world are concerned about the combined effects of multiple chemicals that activate the AhR, and are developing health standards that take into account the fact that people are exposed to mixtures of DLCs, not just one at a time.

Dioxins' Impact

The public health threats posed by dioxins were highlighted dramatically in the public consciousness in the late 1970s and early 1980s. Newspapers and television broadcasts were full of stories about ailing veterans who had been exposed to dioxins through Agent Orange, an herbicide and defoliant used in the Vietnam War.

Concerns about Agent Orange and other DLCs continue today. Research supported by NIEHS and many others, examining the link between dioxin and serious illnesses, has helped lead the U.S. Department of Veterans Affairs (VA) to recognize certain cancers and other health problems as presumptive diseases associated with exposure to Agent Orange or other herbicides during military service. Presumptive diseases are certain diseases that the VA assumes can be related to a Veteran's qualifying military service.

Dioxins were also brought to light in 1982, when the town of Times Beach, Mo., was declared off-limits, because of dioxin contamination. This incident in Missouri, as well as others, helped spark passage of legislation that created Superfund, the environmental program established to address abandoned hazardous waste sites.

In addition to funding work in labs across the nation, NIEHS administers the Superfund Research Program (SRP). SRP involves a network of university grants that are designed to seek solutions to the complex health and environmental issues associated with the nation's hazardous waste sites.

The research conducted by the SRP is a coordinated effort with the EPA, the federal entity charged with cleaning up the worst hazardous waste sites in the country, including those contaminated with dioxins.

Today, the hazards posed by dioxins have faded from public view. And, in fact, the extent of the hazard has diminished in the U.S., as environmental controls significantly reduced the introduction of new industrial sources of dioxin.

However, the problem has not vanished, and the scientific community has continued its work to reduce exposures and treat diseases that arise from them.

What are electric and magnetic fields?

Electric and magnetic fields are invisible areas of energy (also called radiation) that are produced by electricity, which is the movement of electrons, or current, through a wire.

An electric field is produced by voltage, which is the pressure used to push the electrons through the wire, much like water being pushed through a pipe. As the voltage increases, the electric field increases in strength. Electric fields are measured in volts per meter (V/m).

A magnetic field results from the flow of current through wires or electrical devices and increases in strength as the current increases. The strength of a magnetic field decreases rapidly with increasing distance from its source. Magnetic fields are measured in microteslas (μT, or millionths of a tesla).

Electric fields are produced whether or not a device is turned on, whereas magnetic fields are produced only when current is flowing, which usually requires a device to be turned on. Power lines produce magnetic fields continuously because current is always flowing through them. Electric fields are easily shielded or weakened by walls and other objects, whereas magnetic fields can pass through buildings, living things, and most other materials.

Electric and magnetic fields together are referred to as electromagnetic fields, or EMFs. The electric and magnetic forces in EMFs are caused by electromagnetic radiation. There are two main categories of EMFs:

• Higher-frequency EMFs, which include x-rays and gamma rays. These EMFs are in the ionizing radiation part of the electromagnetic spectrum and can damage DNA or cells directly.
• Low- to mid-frequency EMFs, which include static fields (electric or magnetic fields that do not vary with time), magnetic fields from electric power lines and appliances, radio waves, microwaves, infrared radiation, and visible light. These EMFs are in the non-ionizing radiation part of the electromagnetic spectrum and are not known to damage DNA or cells directly. Low- to mid-frequency EMFs include extremely low frequency EMFs (ELF-EMFs) and radiofrequency EMFs. ELF-EMFs have frequencies of up to 300 cycles per second, or hertz (Hz), and radiofrequency EMFs range from 3 kilohertz (3 kHz, or 3,000 Hz) to 300 gigahertz (300 GHz, or 300 billion Hz). Radiofrequency radiation is measured in watts per meter squared (W/m²).

What are common sources of non-ionizing EMFs?

There are both natural and human-made sources of non-ionizing EMFs. The earth’s magnetic field, which causes the needle on a compass to point North, is one example of a naturally occurring EMF.

Human-made EMFs fall into both the ELF and radiofrequency categories of non-ionizing part of the electromagnetic spectrum. These EMFs can come from a number of sources.

Extremely low frequency EMFs (ELF-EMFs). Sources of ELF-EMFs include power lines, electrical wiring, and electrical appliances such as shavers, hair dryers, and electric blankets.

Radiofrequency radiation. The most common sources of radiofrequency radiation are wireless telecommunication devices and equipment, including cell phones, smart meters, and portable wireless devices, such as tablets and laptop computers. In the United States, cell phones currently operate in a frequency range of about 1.8 to 2.2 GHz.

Other common sources of radiofrequency radiation include:

• Radio and television signals. AM/FM radios and older VHF/UHF televisions operate at lower radio frequencies than cell phones. Radio signals are AM (amplitude-modulated) or FM (frequency-modulated). AM radio is used for broadcasting over very long distances, whereas FM radio covers more localized areas. AM signals are transmitted from large arrays of antennas that are placed at high elevation on sites that are off limits to the general public because exposures close to the source can be high. Maintenance workers could receive substantial radiofrequency exposures from AM radio antennas, but the general public would not. FM radio antennas and TV broadcasting antennas, which are much smaller than AM antennas, are generally mounted at the top of high towers. Radiofrequency exposures near the base of these towers are below guideline limits, so exposure of the general population is very low. Sometimes small local radio and TV antennas are mounted on the top of a building; access to the roof of such buildings is usually controlled.
• Radar, satellite stations, magnetic resonance imaging (MRI) devices, and industrial equipment. These operate at somewhat higher radio frequencies than cell phones.
• Microwave ovens used in homes, which also operate at somewhat higher radio frequencies than cell phones. Microwave ovens are manufactured with effective shielding that has reduced the leakage of radiofrequency radiation from these appliances to barely detectable levels.
• Cordless telephones, which can operate on analogue or DECT (Digital Enhanced Cordless Telecommunications) technology and typically emit radio frequencies similar to those of cell phones. However, because cordless phones have a limited range and require a nearby base, their signal strengths are generally much lower than those of cell phones.
• Cell phone base stations. Antenna towers or base stations, including those for mobile phone networks and for broadcasting for radio and for television, emit various types of radiofrequency energy. Because the majority of individuals in the general population are exposed only intermittently to base stations and broadcast antennas, it is difficult to estimate exposures for a population. The strength of these exposures varies based on the population density of the region, the average distance from the source, and the time of day or the day of the week (lower exposures on the weekends or at night). In general, exposures decrease with increasing distance from the source. Exposures among maintenance workers have been found to vary depending on their tasks, the type of antenna, and the location of the worker in relation to the source. Cumulative exposures of such workers are very difficult to estimate.
• Televisions and computer screens produce electric and magnetic fields at various frequencies, as well as static electric fields. The liquid crystal displays found in some laptop and desktop computers do not produce substantial electric or magnetic fields. Modern computers have conductive screens that reduce static fields produced by the screen to normal background levels.
• Wireless local area networks, commonly known as Wi-Fi. These are specific types of wireless networking systems and an increasingly common source of radiofrequency radiation. Wireless networks use radio waves to connect Wi-Fi–enabled devices to an access point that is connected to the internet, either physically or through some form of data connection. Most Wi-Fi devices operate at radio frequencies that are broadly similar to cell phones, typically 2.4 to 2.5 GHz, although in recent years Wi-Fi devices that operate at somewhat higher frequencies (5, 5.3, or 5.8 GHz) have appeared. Radiofrequency radiation exposure from Wi-Fi devices is considerably lower than that from cell phones. Both sources emit levels of radiofrequency radiation that are far below the guideline of 10 W/m ² as specified by the International Commission on Non-Ionizing Radiation Protection.
• Digital electric and gas meters, also known as “smart meters.” These devices, which operate at about the same radio frequencies as cell phones, transmit information on consumption of electricity or gas to utility companies. Smart meters produce very low level fields that sometimes cannot be distinguished from the total background radiofrequency radiation levels inside a home.

For household appliances and other devices used in the home that require electricity, magnetic field levels are highest near the source of the field and decrease rapidly the farther away the user is from the source. Magnetic fields drop precipitously at a distance of about 1 foot from most appliances. For computer screens, at a distance of 12–20 inches from the screen that most persons using computers sit, magnetic fields are similarly dramatically lower.

Why are non-ionizing EMFs studied in relation to cancer?

Power lines and electrical appliances that emit non-ionizing EMFs are present everywhere in homes and workplaces. For example, wireless local networks are nearly always “on” and are increasingly commonplace in homes, schools, and many public places.

No mechanism by which ELF-EMFs or radiofrequency radiation could cause cancer has been identified. Unlike high-energy (ionizing) radiation, EMFs in the non-ionizing part of the electromagnetic spectrum cannot damage DNA or cells directly. Some scientists have speculated that ELF-EMFs could cause cancer through other mechanisms, such as by reducing levels of the hormone melatonin. There is some evidence that melatonin may suppress the development of certain tumors.

Studies of animals have not provided any indications that exposure to ELF-EMFs is associated with cancer. The few high-quality studies in animals have provided no evidence that Wi-Fi is harmful to health. The National Institute of Environmental Health Sciences, which is part of the National Institutes of Health, is carrying out a large-scale study in rodents of exposure to radiofrequency energy (the type used in cell phones). This investigation is being conducted in highly specialized labs that can specify and control sources of radiation and measure their effects. Preliminary results from this study were released in May 2016.

Although there is no known mechanism by which non-ionizing EMFs could damage DNA and cause cancer, even a small increase in risk would be of clinical importance given how widespread exposure to these fields is.

What have studies shown about possible associations between non-ionizing EMFs and cancer in children?

Numerous epidemiologic studies and comprehensive reviews of the scientific literature have evaluated possible associations between exposure to non-ionizing EMFs and risk of cancer in children. (Magnetic fields are the component of non-ionizing EMFs that are usually studied in relation to their possible health effects.) Most of the research has focused on leukemia and brain tumors, the two most common cancers in children. Studies have examined associations of these cancers with living near power lines, with magnetic fields in the home, and with exposure of parents to high levels of magnetic fields in the workplace. No consistent evidence for an association between any source of non-ionizing EMF and cancer has been found.

Exposure from power lines. Although a study in 1979 pointed to a possible association between living near electric power lines and childhood leukemia, more recent studies have had mixed findings. Most of these studies did not find an association or found one only for those children who lived in homes with very high levels of magnetic fields, which are present in few residences.

Several studies have analyzed the combined data from multiple studies of power line exposure and childhood leukemia:

• A pooled analysis of nine studies reported a twofold increase in risk of childhood leukemia among children with exposures of 0.4 μT or higher. Less than 1 percent of the children in the studies experienced this level of exposure.
• A meta-analysis of 15 studies observed a 1.7-fold increase in childhood leukemia among children with exposures of 0.3 μT or higher. A little more than 3 percent of children in the studies experienced this level of exposure.
• More recently, a pooled analysis of seven studies published after 2000 reported a 1.4-fold increase in childhood leukemia among children with exposures of 0.3 μT or higher. However, less than one half of 1 percent of the children in the studies experienced this level of exposure.

For the two pooled studies and the meta-analysis, the number of highly exposed children was too small to provide stable estimates of the dose–response relationship. This means that the findings could be interpreted to reflect linear increases in risk, a threshold effect at 0.3 or 0.4 μT, or no significant increase.

The interpretation of the finding of increased childhood leukemia risk among children with the highest exposures (at least 0.3 μT) is unclear.

Exposure from electrical appliances. Another way that children can be exposed to magnetic fields is from household electrical appliances. Although magnetic fields near many electrical appliances are higher than those near power lines, appliances contribute less to a person’s total exposure to magnetic fields because most appliances are used for only short periods of time. And moving even a short distance from most electrical appliances reduces exposure dramatically. Again, studies have not found consistent evidence for an association between the use of household electrical appliances and risk of childhood leukemia.

Exposure to Wi-Fi. In view of the widespread use of Wi-Fi in schools, the UK Health Protection Agency (now part of Public Health England) has conducted the largest and most comprehensive measurement studies to assess exposures of children to radiofrequency electromagnetic fields from wireless computer networks. This agency concluded that radiofrequency exposures were well below recommended maximum levels and that there was “no reason why Wi-Fi should not continue to be used in schools and in other places”.

A review of the published literature concluded that the few high-quality studies to date provide no evidence of biological effects from Wi-Fi exposures.

Exposure to cell phone base stations. Few studies have examined cancer risk in children living close to cell phone base stations or radio or television transmitters. None of the studies that estimated exposures on an individual level found an increased risk of pediatric tumors.

Parental exposure and risk in offspring. Several studies have examined possible associations between maternal or paternal exposure to high levels of magnetic fields before conception and/or during pregnancy and the risk of cancer in their future children. The results to date have been inconsistent. This question requires further evaluation.

Exposure and cancer survival. A few studies have investigated whether magnetic field exposure is associated with prognosis or survival of children with leukemia. Several small retrospective studies of this question have yielded inconsistent results. An analysis that combined prospective data for more than 3,000 children with acute lymphoid leukemia from eight countries showed that ELF magnetic field exposure was not associated with their survival or risk of relapse.

What have studies shown about possible associations between non-ionizing EMFs and cancer in adults?

Many studies have examined the association between non-ionizing EMF exposure and cancer in adults, of which few studies have reported evidence of increased risk.

Residential exposures. The majority of epidemiologic studies have shown no relationship between breast cancer in women and exposure to extremely low frequency EMFs (ELF-EMFs) in the home, although a few individual studies have suggested an association; only one reported results that were statistically significant.

Workplace exposures to ELF radiation. Several studies conducted in the 1980s and early 1990s reported that people who worked in some electrical occupations that exposed them to ELF radiation (such as power station operators and telephone line workers) had higher-than-expected rates of some types of cancer, particularly leukemia, brain tumors, and male breast cancer. Most of the results were based on participants’ job titles and not on actual measurements of their exposures. More recent studies, including some that considered exposure measurements as well as job titles, have generally not shown an increasing risk of leukemia, brain tumors, or female breast cancer with increasing exposure to magnetic fields at work.

Workplace exposures to radiofrequency radiation. A limited number of studies have evaluated risks of cancer in workers exposed to radiofrequency radiation. A large study of U.S. Navy personnel found no excess of brain tumors among those with a high probability of exposure to radar (including electronics technicians, aviation technicians, and fire control technicians); however, nonlymphocytic leukemia, particularly acute myeloid leukemia, was increased in electronics technicians in aviation squadrons, but not in Navy personnel in the other job categories. A case-control study among U.S. Air Force personnel found the suggestion of an increased risk of brain cancer among personnel who maintained or repaired radiofrequency or microwave-emitting equipment. A case-control study found the suggestion of an increased risk of death from brain cancer among men occupationally exposed to microwave and/or radiofrequency radiation, with all of the excess risk among workers in electrical and electronics jobs involving design, manufacture, repair, or installation of electrical or electronics equipment. There was no evidence that electrical utility workers who were exposed to pulsed electromagnetic fields produced by power lines were more likely to develop brain tumors or leukemia than the general population. Employees of a large manufacturer of wireless communication products were not more likely to die from brain tumors or cancers of the hematopoietic or lymphatic system than the general population.

What do expert organizations conclude about the cancer risk from EMFs?

In 2002, the International Agency for Research on Cancer (IARC), a component of the World Health Organization, appointed an expert Working Group to review all available evidence on static and extremely low frequency electric and magnetic fields. The Working Group classified ELF-EMFs as “possibly carcinogenic to humans,” based on limited evidence from human studies in relation to childhood leukemia. Static electric and magnetic fields and extremely low frequency electric fields were determined “not classifiable as to their carcinogenicity to humans”.

In 2015, the European Commission Scientific Committee on Emerging and Newly Identified Health Risks reviewed electromagnetic fieldsExit Disclaimer in general, as well as cell phones in particular. It found that, overall, epidemiologic studies of extremely low frequency fields show an increased risk of childhood leukemia with estimated daily average exposures above 0.3 to 0.4 μT, although no mechanisms have been identified and there is no support from experimental studies that explains these findings. It also found that the epidemiologic studies on radiofrequency exposure do not show an increased risk of brain tumors or other cancers of the head and neck region, although the possibility of an association with acoustic neuroma remains open.

Do children have a higher risk of developing cancer due to cell phone use than adults?

There are theoretical considerations as to why the possible risk should be investigated separately in children. Their nervous systems are still developing and, therefore, more vulnerable to factors that may cause cancer. Their heads are smaller than those of adults and consequently have a greater proportional exposure to the field of radiofrequency radiation that is emitted by cell phones. And, children have the potential of accumulating more years of cell phone exposure than adults do.

Thus far, the data from studies in children with cancer do not support this theory. The first published analysis came from a large case-control study called CEFALO, which was conducted in Denmark, Sweden, Norway, and Switzerland. The study included children who were diagnosed with brain tumors between 2004 and 2008, when their ages ranged from 7 to 19. Researchers did not find an association between cell phone use and brain tumor risk either by time since initiation of use, amount of use, or by the location of the tumor.

What can cell phone users do to reduce their exposure to radiofrequency energy?

The FDA has suggested some steps that concerned cell phone users can take to reduce their exposure to radiofrequency energy:

• Reserve the use of cell phones for shorter conversations or for times when a landline phone is not available.
• Use a device with hands-free technology, such as wired headsets, which place more distance between the phone and the head of the user.

Hands-free kits reduce the amount of radiofrequency energy exposure to the head because the antenna, which is the source of energy, is not placed against the head. Exposures decline dramatically when cell phones are used hands-free.

How common is brain cancer? Has the incidence of brain cancer changed over time?

Brain cancer incidence and mortality (death) rates have changed little in the past decade.

In the United States, 23,770 new diagnoses and 16,050 deaths from brain and other central nervous system cancers are estimated for 2016.

The 5-year relative survival for brain cancers diagnosed from 2005 through 2011 was 35 percent. This is the percentage of people diagnosed with brain cancer who will still be alive 5 years after diagnosis compared with the survival of a person of the same age and sex who does not have cancer.

The risk of developing brain cancer increases with age. From 2008 through 2012, there were fewer than 5 brain cancer cases for every 100,000 people in the United States under age 65, compared with approximately 19 cases for every 100,000 people in the United States who were ages 65 or older.

What is erionite?

Erionite is a naturally occurring fibrous mineral that belongs to a group of minerals called zeolites. It forms fibrous masses in the hollows of rock formations. Some of the mineral’s properties are similar to those of asbestos; for example, the fibers pose a hazard only if they are disturbed and become airborne.

How are people exposed to erionite?

In the past, occupational exposure occurred during erionite mining and production operations, but erionite is no longer mined or marketed for commercial purposes. Erionite-related disease has been reported most often among road construction and maintenance workers who may have been exposure to erionite-containing gravel used in road surfacing.

Little is known about current exposures experienced by workers in the United States. However, erionite is found in some other commercial zeolite products. Therefore, the use of other zeolites may result in exposure to erionite among workers and members of the general population who use the zeolites in various processes and products. The commercial uses of other natural zeolites include pet litter, soil conditioners, animal feed, wastewater treatment, and gas absorbents.

Erionite is a fibrous mineral whose properties are similar to those of asbestos.

Which cancers are associated with exposure to erionite?

Exposure to erionite is associated with increased risks of lung cancer and mesothelioma.

How can exposures be reduced?

There are no regulatory or consensus standards or occupational exposure limits for airborne erionite fibers. The U.S. Occupational Safety and Health Administration’s guidance for working with asbestos could serve as a model for limiting the generation and inhalation of dust known or thought to be contaminated with erionite.

What is ethylene oxide?

At room temperature, ethylene oxide is a flammable colorless gas with a sweet odor. It is used primarily to produce other chemicals, including antifreeze. In smaller amounts, ethylene oxide is used as a pesticide and a sterilizing agent. The ability of ethylene oxide to damage DNA makes it an effective sterilizing agent but also accounts for its cancer-causing activity.

A model of the ethylene oxide molecule.

How are people exposed to ethylene oxide?

The primary routes of human exposure to ethylene oxide are inhalation and ingestion, which may occur through occupational, consumer, or environmental exposure. Because ethylene oxide is highly explosive and reactive, the equipment used for its processing generally consists of tightly closed and highly automated systems, which decreases the risk of occupational exposure.

Despite these precautions, workers and people who live near industrial facilities that produce or use ethylene oxide may be exposed to ethylene oxide through uncontrolled industrial emissions. The general population may also be exposed through tobacco smoke and the use of products that have been sterilized with ethylene oxide, such as medical products, cosmetics, and beekeeping equipment.

Which cancers are associated with exposure to ethylene oxide?

Lymphoma and leukemia are the cancers most frequently reported to be associated with occupational exposure to ethylene oxide. Stomach and breast cancers may also be associated with ethylene oxide exposure.

How can exposures be reduced?

The U.S. Occupational Safety and Health Administration has information about limiting occupational exposure to ethylene oxide.

What is formaldehyde?

Formaldehyde is a colorless, strong-smelling, flammable chemical that is produced industrially and used in building materials such as particleboard, plywood, and other pressed-wood products. In addition, it is commonly used as a fungicide, germicide, and disinfectant, and as a preservative in mortuaries and medical laboratories. Formaldehyde also occurs naturally in the environment. It is produced during the decay of plant material in the soil and during normal chemical processes in most living organisms. It is also a combustion product found in tobacco smoke.

Formaldehyde is commonly used as a preservative.

How are people exposed to formaldehyde?

People are exposed primarily by inhaling formaldehyde gas or vapor from the air or by absorbing liquids containing formaldehyde through the skin. Workers who produce formaldehyde or products that contain formaldehyde—as well as laboratory technicians, certain health care professionals, and mortuary employees—may be exposed to higher levels of formaldehyde than people in the general population.

The general public may be exposed to formaldehyde by breathing contaminated air from sources such as pressed-wood products, tobacco smoke, and automobile tailpipe emissions. Another potential source of exposure to formaldehyde is the use of unvented fuel-burning appliances, such as gas stoves, wood-burning stoves, and kerosene heaters.

Which cancers are associated with exposure to formaldehyde?

Studies of workers exposed to high levels of formaldehyde, such as industrial workers and embalmers, have found that formaldehyde causes myeloid leukemia and rare cancers, including cancers of the paranasal sinuses, nasal cavity, and nasopharynx.

How can exposures be reduced?

The U.S. Environmental Protection Agency recommends the use of “exterior-grade” pressed-wood products to limit formaldehyde exposure in the home. Formaldehyde levels in homes and work settings can also be reduced by ensuring adequate ventilation, moderate temperatures, and reduced humidity levels through the use of air conditioners and dehumidifiers.

What are indoor emissions from the household combustion of coal?

Burning coal inside the home for the purposes of heating or cooking produces particulate and gas emissions that may contain a number of harmful chemicals, such as benzene, carbon monoxide, formaldehyde, and polycyclic aromatic hydrocarbons.

Burning coal inside the home can release a number of harmful chemicals.

How are people exposed to indoor emissions from the household combustion of coal?

People in some parts of the world, particularly in certain regions of China, have been exposed to indoor emissions from coal combustion through the use of unvented stoves and fire pits.

Which cancers are associated with exposure to indoor coal combustion emissions?

Lung cancer is associated with exposure to indoor coal combustion emissions.

How can exposures be reduced?

Installing indoor stoves with chimneys can reduce the level of indoor air pollution.

Sunlamps and tanning beds promise consumers a bronzed body year-round, but the ultraviolet (UV) radiation from these devices poses serious health risks.

“Although some people think that a tan gives them a ‘healthy’ glow, any tan is a sign of skin damage,” says Sharon Miller, M.S.E.E., a Food and Drug Administration (FDA) scientist and international expert on UV radiation and tanning.

“A tan is the skin’s reaction to exposure to UV rays,” says Miller. “Recognizing exposure to the rays as an ‘insult,’ the skin acts in self-defense by producing more melanin, a pigment that darkens the skin. Over time, this damage will lead to prematurely aged skin and, in some cases, skin cancer.”

Two types of UV radiation that penetrate the skin are UV-B and UV-A rays.

• UV-B rays penetrate the top layers of skin and are most responsible for sunburns.
• UV-A rays penetrate to the deeper layers of the skin and are often associated with allergic reactions, such as a rash.

Both UV-B and UV-A rays damage the skin and can lead to skin cancer. Tanning salons use lamps that emit both UV-A and UV-B radiation.

Cancer Risk

Exposure to UV radiation—whether from the sun or from artificial sources such as sunlamps used in tanning beds—increases the risk of developing skin cancer, according to the National Cancer Institute (NCI). Melanoma, the deadliest form of skin cancer, is linked to getting severe sunburns, especially at a young age.

In July 2009, the International Agency for Research on Cancer (IARC), part of the World Health Organization, concluded that tanning devices that emit UV radiation are more dangerous than previously thought. IARC moved these devices into the highest cancer risk category: “carcinogenic to humans.” Previously, it had categorized the devices as “probably carcinogenic to humans.”

Development of cancer is a long process that may take decades. Therefore, IARC also recommended banning commercial indoor tanning for those younger than 18 years to protect them from the increased risk for melanoma and other skin cancers.

IARC’s conclusions and recommendations were based on its 2006 review of 19 studies conducted over 25 years on the use of indoor tanning equipment. The review found evidence of:

• An association between indoor tanning and two types of skin cancer: squamous cell carcinoma and melanoma;
• An association between UV-emitting tanning devices and cancer of the eye (ocular melanoma);
• Both UV-A and UV-B rays causing DNA damage, which can lead to skin cancer in laboratory animals and humans; and
• The risk of melanoma of the skin increasing by 75 percent when tanning bed use started before age 35.

IARC’s review had some limitations, says Ron Kaczmarek, M.D., M.P.H., an FDA epidemiologist who analyzed the review. Limitations include possible inaccuracy of people’s memories of their tanning experiences, not knowing the amount of UV radiation emitted by each tanning device, and the inability to separate the effects of individuals’ indoor and outdoor exposure. Nevertheless, IARC concluded that there is convincing evidence of an association between the use of indoor tanning equipment and melanoma risk, and that the use of tanning beds should be discouraged.

“It’s well established that UV radiation from the sun causes skin cancer,” says Miller. “Since lamps used in tanning beds emit UV radiation, the use of indoor tanning devices also increases your risk of skin cancer.”

Other Risks

In addition to the serious risk of skin cancer, tanning can cause:

• Premature aging. Tanning causes the skin to lose elasticity and wrinkle prematurely. This leathery look may not show up until many years after you’ve had a tan or sunburn.
• Immune suppression. UV-B radiation may suppress proper functioning of the body’s immune system and the skin’s natural defenses, leaving you more vulnerable to diseases, including skin cancer.
• Eye damage. Exposure to UV radiation can cause irreversible damage to the eyes.
• Allergic reaction. Some people who are especially sensitive to UV radiation may develop an itchy red rash and other adverse effects.

Advocates of tanning devices sometimes argue that using these devices is less dangerous than sun tanning because the intensity of UV radiation and the time spent tanning can be controlled. But there is no evidence to support these claims. In fact, sunlamps may be more dangerous than the sun because they can be used at the same high intensity every day of the year—unlike the sun whose intensity varies with the time of day, the season, and cloud cover.

Tanning in Children and Teens

FDA is particularly concerned about children and teens being exposed to UV rays. Intermittent exposures to intense UV radiation leading to sunburns, especially in childhood and teen years, increase the risk of melanoma, according to NCI.

FDA believes that limiting sun exposure and using sunscreen or sunblock are particularly important for children since these measures can prevent sunburn at a young age.

NCI reports that women who use tanning beds more than once a month are 55 percent more likely to develop melanoma. Teenage girls and young women make up a growing number of tanning bed customers.

“Young people may not think they are vulnerable to skin cancer,” says Kaczmarek. “They have difficulty thinking about their own mortality.” Yet of the more than 68,000 people in the United States who will learn they have melanoma this year, one out of eight will die from it, according to NCI estimates. In addition, the American Academy of Dermatology reports that melanoma is the second most common cancer in women 20 to 29 years old.

Some states are considering laws to ban those under age 18 from using tanning beds. And many states now have laws that require minors to have a parent’s consent or be accompanied by a parent to the tanning facility.

FDA’s current performance standard requires that a sunlamp product’s label include a recommended exposure schedule. (Performance standards, among other things, help ensure devices function as intended, which may help to reduce risks to consumers.) FDA has advised manufacturers that this schedule should provide for exposures of no more than three sessions in the first week.

In an NCI-sponsored study published in September 2009 in the Archives of Dermatology, the study researchers hired and trained college students to pose as 15-year-old, fair-skinned girls who had never tanned before. By telephone, the students asked more than 3,600 tanning facilities in all 50 states about their practices.

Less than 11 percent of the facilities followed FDA’s recommended exposure schedule of three or fewer sessions the first week. About 71 percent said they would allow a teen to tan all seven days the first week, and many promoted frequent tanning with “unlimited tanning” discount price packages.

About 87 percent of the facilities required parental consent, leading the researchers to conclude that “many parents are allowing their teens to tan and are providing written consent or accompaniment.”

FDA Regulation

FDA regulates products that emit radiation, including sunlamp products and products that use sunlamp products, such as tanning beds and tanning booths.

FDA also regulates medical devices and classifies them into one of three classes: class I, class II, and class III. FDA classifies devices based on the risks associated with the device. Class I devices are low risk and are subject to the least regulatory controls. Class II devices, such as sunlamp products, are higher risk devices than class I devices and generally must meet additional regulatory requirements to provide a reasonable assurance of the device’s safety and effectiveness.

Manufacturers of sunlamp products must comply with applicable FDA regulations, including the current performance standard for sunlamp products.

FDA previously reclassified sunlamp products from class I to class II, and that order was effective on September 2, 2014. That reclassification established additional requirements for the devices (called “special controls”) and required manufacturers to submit a premarket notification, which is commonly called a 510(k).

In December 2015, FDA proposed a rule to amend the sunlamp products and UV lamps performance standard. FDA also proposed to restrict sunlamp product use to users 18 and older, and to require adult users to sign a risk acknowledgement certification before their first tanning sessions and every six months after that.

The Riskiest Practices

FDA, NCI, the American Academy of Dermatology, and other health organizations advise limiting exposure to natural UV radiation from the sun and avoiding artificial UV sources such as tanning beds entirely.

All use of tanning beds increases the risk of skin cancer. Certain practices are especially dangerous. These include:

• Failing to wear the goggles provided, which can lead to short- and long-term eye injury.
• Starting with long exposures (close to the maximum time for the particular tanning bed), which can lead to burning. Because sunburn takes 6 to 48 hours to develop, you may not realize your skin is burned until it’s too late.
• Failing to follow manufacturer-recommended exposure times on the label for your skin type.
• Tanning while using certain medications or cosmetics that may make you more sensitive to UV rays. Talk to your doctor or pharmacist first.

Melanoma: One Woman's Story

Brittany Lietz Cicala of Chesapeake Beach, Md., began tanning indoors at age 17. She stopped at age 20 when she was diagnosed with melanoma, the deadliest form of skin cancer. The former Miss Maryland says she used tanning beds at least four times a week, and sometimes every day.

"Growing up, until I started using tanning beds, my parents were very strict about me wearing sunscreen," says Cicala. Although she also tanned in the summer sun during her 3 years of tanning bed use, Cicala estimates that 90 percent of her UV exposure was in tanning beds during this period.

In the 4 years since she was diagnosed with melanoma, Cicala’s surgeries have left her with about 25 scars. Cicala gets a head-to-toe skin exam every 3 months, which usually results in removal of a suspicious growth.

What are strong inorganic acid mists containing sulfuric acid?

At room temperature, sulfuric acid is a clear, colorless, oily, corrosive liquid. Strong inorganic acid mists containing sulfuric acid may be generated during various manufacturing processes.

Copper smelting and other manufacturing processes generate mists containing sulfuric acid.

How are people exposed to strong inorganic acid mists containing sulfuric acid?

The major routes of occupational exposure are inhalation, ingestion, or absorption through the skin. Workers with potential exposure include those involved in manufacturing phosphate fertilizer, isopropanol, sulfuric acid, nitric acid, and lead batteries. Exposure may also occur during copper smelting, pickling (removing scale and oxides from metal surfaces), and other acid treatment of metals.

Which cancers are associated with exposure to strong inorganic acid mists containing sulfuric acid?

Occupational exposure to strong inorganic acid mists containing sulfuric acid is associated with increased risks of laryngeal and lung cancers.

How can exposures be reduced?

The U.S. Occupational Safety & Health Administration has information about exposure limits for sulfuric acid.

What are mineral oils?

The name mineral oil has been used to describe many colorless, odorless liquids. Most often, the term refers to a liquid by-product of the distillation of petroleum to produce gasoline and other petroleum-based products from crude oil. These oils, including lubricant base oils and products derived from them, are used in manufacturing, mining, construction, and other industries.

A complete description of mineral oils should include how the oils are refined. Oils used in cosmetic products are typically highly refined, whereas those used in automotive oils and fluids tend to be unrefined or only mildly treated. Highly refined products are not covered in this section.

Workers in engine repair are among those most commonly exposed to mineral oils.

How are people exposed to mineral oils?

Occupational exposure to mineral oils may occur among workers in various industries, including the manufacture of automobiles, airplanes, steel products, screws, pipes, and transformers. Workers in brass and aluminum production, engine repair, copper mining, and newspaper and commercial printing may also be exposed to mineral oils. The general population may be exposed to mineral oils that occur naturally or are present as environmental contaminants.

Which cancers are associated with exposure to mineral oils?

Exposure to mineral oils is strongly associated with an increased risk of nonmelanoma skin cancer, particularly of the scrotum.

How can exposures be reduced?

The U.S. Occupational Safety & Health Administration provides information about exposure limits to mineral oils.

What are nickel and nickel compounds?

Nickel is a silvery-white metallic element found in the earth’s crust. It can be combined with other elements to form nickel compounds. Because of its unique properties, nickel has many industrial uses. Most nickel is used in metal alloys because it imparts useful properties, such as corrosion resistance, heat resistance, hardness, and strength.

Grinding, mining, welding, and other occupations expose workers to nickel compounds.

How are people exposed to nickel and nickel compounds?

Occupational exposure is common in workplaces where nickel and nickel compounds are produced or used, including mining, smelting, welding, casting, and grinding. Occupational exposure to nickel occurs mainly through inhalation of dust particles and fumes or through skin contact.

The general population is exposed to low levels of nickel in air, water, food, and tobacco smoke. Nickel and its compounds get into the atmosphere through natural processes, such as the spread of dust and volcanic eruptions by the wind, as well as through industrial activities. The general public may also be exposed through nickel-plated materials, such as coins, jewelry, and stainless steel cooking and eating utensils.

Which cancers are associated with exposure to nickel and nickel compounds?

Exposure to various nickel compounds is associated with increased risks of lung cancer and nasal cancer.

How can exposures be reduced?

Exposures of the general population to nickel compounds are almost always too low to be of concern. To protect workers, the U.S. Occupational Safety & Health Administration has issued exposure limits for nickel compounds.

Radiation of certain wavelengths, called ionizing radiation, has enough energy to damage DNA and cause cancer. Ionizing radiation includes radon, x-rays, gamma rays, and other forms of high-energy radiation. Lower-energy, non-ionizing forms of radiation, such as visible light and the energy from cell phones and electromagnetic fields, do not damage DNA and have not been found to cause cancer.

Radon

Radon is a radioactive gas given off by rocks and soil. Radon is formed when the radioactive element radium breaks down. Radium in turn is formed when the radioactive elements uranium and thorium break down. People who are exposed to high levels of radon have an increased risk of lung cancer.

If you live in an area of the country that has high levels of radon in its rocks and soil, you may wish to test your home for this gas. Home radon tests are easy to use and do not cost much. Most hardware stores sell test kits. There are many ways to lessen the amount of radon in a home to a safe level.

X-Rays and Other Sources of Radiation

High-energy radiation, such as x-rays, gamma rays, alpha particles, beta particles, and neutrons, can damage DNA and cause cancer. These forms of radiation can be released in accidents at nuclear power plants and when atomic weapons are made, tested, or used.

Certain medical procedures, such as chest x-rays, computed tomography (CT) scans, positron emission tomography (PET) scans, and radiation therapy can also cause cell damage that leads to cancer. However, the risks of cancer from these medical procedures are very small, and the benefit from having them is almost always greater than the risks.

Talk with your doctor if you think you may be at risk for cancer because you were exposed to radiation. People considering CT scans should talk with their doctors about whether the procedure is necessary for them and about its risks and benefits. Cancer patients may want to talk with their doctors about how radiation treatment could increase their risk for a second cancer later on.

​​​​​What is radon?

Radon is a radioactive gas that is released from the normal decay of the elements uranium, thorium, and radium in rocks and soil. The invisible, odorless gas seeps up through the ground and diffuses into the air. In a few areas, depending on local geology, radon dissolves into ground water and can be released into the air when the water is used. Radon gas usually exists at very low levels outdoors, but the gas can accumulate in areas without adequate ventilation, such as underground mines.

How are people exposed to radon?

Radon is present in nearly all air, so everyone breathes in radon every day, usually at very low levels. Radon can enter homes through cracks in floors, walls, or foundations, and collect indoors. It can also be released from building materials or from water obtained from wells that contain radon. Radon levels may be higher in homes that are well insulated, tightly sealed, and/or built on soil rich in the elements uranium, thorium, and radium. Basements and first floors typically have the highest radon levels because of their closeness to the ground.

Workers employed in uranium, hard rock, and phosphate mining potentially are exposed to radon at high concentrations. Uranium miners generally are believed to have the highest exposures.

Which cancers are associated with exposure to radon?

Radon was identified as a health problem when scientists noted that underground uranium miners who were exposed to it died of lung cancer at high rates. Experimental studies in animals confirmed the results of the miner studies by showing higher rates of lung tumors among rodents exposed to high levels of radon. There has been a suggestion of an increased risk of leukemia associated with radon exposure in adults and children; the evidence, however, is not conclusive.

What is secondhand tobacco smoke?

Secondhand tobacco smoke is the combination of the smoke given off by a burning tobacco product and the smoke exhaled by a smoker. It is also called environmental tobacco smoke, involuntary smoke, and passive smoke.

More than 7,000 chemicals have been identified in secondhand tobacco smoke. At least 69 of these chemicals are known to cause cancer, including arsenic, benzene, beryllium, chromium, and formaldehyde.

At least 69 chemicals found in secondhand tobacco smoke are carcinogens.

How are people exposed to secondhand smoke?

People can be exposed to secondhand smoke in homes, cars, the workplace, and public places. In the United States, the source of most secondhand smoke is from cigarettes, followed by pipes, cigars, and other tobacco products.

Which cancers are associated with secondhand smoke?

Inhaling secondhand smoke causes lung cancer in nonsmokers. Some research also suggests that secondhand smoke may increase the risk of breast cancer, nasal sinus cavity cancer, and nasopharyngeal cancer in adults and leukemia, lymphoma, and brain tumors in children, although more research is needed on this subject.

How can exposures to nonsmokers be reduced?

There is no safe level of exposure to secondhand smoke; even low levels of secondhand smoke can be harmful. In the United States, legislation has helped to reduce nonsmokers' exposure to secondhand smoke. Federal law bans smoking on all domestic airline flights, nearly all flights between the United States and foreign destinations, interstate buses, and most trains. Smoking is also banned in most federally owned buildings. Many state and local governments have also passed laws prohibiting smoking in public facilities, such as schools, hospitals, and airports, as well as private workplaces, including restaurants and bars.

Internationally, a growing number of nations require all workplaces, including bars and restaurants, to be smoke free.

​​​​​​What is soot?

Soot is a byproduct of the incomplete burning of organic (carbon-containing) materials, such as wood, fuel oil, plastics, and household refuse. The fine black or brown powder that makes up soot may contain a number of carcinogens, including arsenic, cadmium, and chromium.

Soot comes from the incomplete burning of organic materials, such as wood.

How are people exposed to soot?

People may be exposed to soot by inhalation, ingestion, or absorption through the skin. Chimney sweeps likely have the highest occupational exposure to soot. Heating-unit service personnel, brick masons, building demolition personnel, horticulturists, and anyone who works where organic materials are burned may also be exposed through their work. The general public may be exposed through fireplaces, furnaces, engine exhaust, and particulate emissions from any combustion source.

Which cancers are associated with exposure to soot?

Exposure to soot was first associated with skin cancer of the scrotum among British chimney sweeps in 1775. Since then, many studies have found that chimney sweeps have an increased risk of scrotal and other skin cancers. Studies of chimney sweeps in several European countries have also found associations with other cancers, including lung, esophageal, and bladder cancers.

How can exposures be reduced?

In the United States, professional organizations for chimney sweeps keep members up to date on changing technology and safety issues.

The sun, sunlamps, and tanning booths all give off ultraviolet (UV) radiation. Exposure to UV radiation causes early aging of the skin and damage that can lead to skin cancer.

People of all ages and skin tones should limit the amount of time they spend in the sun, especially between mid-morning and late afternoon, and avoid other sources of UV radiation, such as tanning beds. Keep in mind that UV radiation is reflected by sand, water, snow, and ice and can go through windshields and windows. Even though skin cancer is more common among people with a light skin tone, people of all skin tones can develop skin cancer, including those with dark skin.

Follow these tips to protect your skin from sunlight.

• Wear a hat with a wide brim all around that shades your face, neck, and ears. Baseball caps and some sun visors protect only parts of your skin.
• Wear sunglasses that block UV radiation to protect the skin around your eyes.
• Wear long sleeves and long pants. Tightly woven, dark fabrics are best. Some fabrics are rated with an ultraviolet protection factor (UPF). The higher the rating, the greater the protection from sunlight.
• Use sunscreen products with a sun protection factor (SPF) of at least 15. (Some doctors suggest using a product with an SPF of at least 30.) Apply the product’s recommended amount to uncovered skin 30 minutes before going outside, and apply again every two hours or after swimming or sweating.

Keep in mind that the sun's rays...

• are strongest between 10:00 a.m. and 4:00 p.m.
• can go through light clothing, windshields, windows, and clouds
• are reflected by sand, water, snow, ice, and pavement

​​​​​​What is thorium?

Thorium is a naturally occurring radioactive metal that is found in soil, rock, and water. It is formed by the radioactive decay of uranium. Minerals such as monazite, thorite, and thorianite are rich in thorium and may be mined for the metal.

Thorium has coloring properties that have made it useful in ceramic glazes. Thorium also has been widely used in lantern mantles for the brightness it imparts (though alternatives are replacing it), and in welding rods, which burn better with small amounts of added thorium. Until the 1950s, thorium dioxide was used as a contrast agent (called Thorotrast) in medical radiology.

Thorium is a naturally occurring radioactive metal found in soil, rock, and water.

How are people exposed to thorium?

The primary ways people are exposed to thorium are inhalation, intravenous injection, ingestion, and absorption through the skin. More than 2.5 million people worldwide were exposed to thorium in Thorotrast between 1930 and 1950. Once injected, Thorotrast remains in the body, resulting in lifelong exposure to thorium.

Although thorium is widespread in the environment, most people are not exposed to dangerous levels of the metal. However, people who live near thorium-mining areas or facilities that manufacture products with thorium may have increased exposure, especially if their water comes from a private well. Analytical laboratories can test water for thorium content.

Which cancers are associated with exposure to thorium?

Studies of patients who received intravascular injections of Thorotrast found an increased risk of liver tumors among these individuals. And there is research evidence that inhaling thorium dust increases the risk of lung and pancreatic cancer. Individuals exposed to thorium also have an increased risk of bone cancer because thorium may be stored in bone.

How can exposures be reduced?

Occasionally, household items may be found to contain thorium, such as some older ceramic wares in which uranium was used in the glaze, or gas lantern mantles. Although these exposures generally do not pose serious health risks, such household items should be retired from use to avoid unnecessary exposures. A radiation counter is required to confirm if ceramics contain thorium.

Tobacco use is a leading cause of cancer and of death from cancer. People who use tobacco products or who are regularly around environmental tobacco smoke (also called secondhand smoke) have an increased risk of cancer because tobacco products and secondhand smoke have many chemicals that damage DNA.

Tobacco use causes many types of cancer, including cancer of the lung, larynx (voice box), mouth, esophagus, throat, bladder, kidney, liver, stomach, pancreas, colon and rectum, and cervix, as well as acute myeloid leukemia. People who use smokeless tobacco (snuff or chewing tobacco) have increased risks of cancers of the mouth, esophagus, and pancreas.

There is no safe level of tobacco use. People who use any type of tobacco product are strongly urged to quit. People who quit smoking, regardless of their age, have substantial gains in life expectancy compared with those who continue to smoke. Also, quitting smoking at the time of a cancer diagnosis reduces the risk of death.

What is trichloroethylene?

Trichloroethylene (TCE) is a volatile, colorless liquid organic chemical. TCE does not occur naturally and is created by chemical synthesis. It is used primarily to make refrigerants and other hydrofluorocarbons and as a degreasing solvent for metal equipment. TCE is also used in some household products, such as cleaning wipes, aerosol cleaning products, tool cleaners, paint removers, spray adhesives, and carpet cleaners and spot removers. Commercial dry cleaners also use trichloroethylene as a spot remover.

Trichloroethylene, which can cause kidney cancer, was originally developed as an anesthetic.

How are people exposed to trichloroethylene?

TCE may be found in the air, water, and soil at places where it is produced or used. It breaks down slowly and remains in the environment for a long time. It readily passes through soil and can accumulate in groundwater.

People in the general population can be exposed to trichloroethylene by inhaling it in indoor and outdoor air, drinking contaminated water, or eating foods that have been washed or processed with contaminated water. Because this chemical was used extensively by the US military to degrease equipment, contaminated soil and groundwater can be found near many current and former military bases.

People who work with TCE may inhale the chemical from the air and absorb it through the skin.

Historically, TCE was used as a surgical anesthetic and inhaled analgesic. The Food and Drug Administration banned such use in the United States in 1977.

Which cancers are associated with exposure to trichloroethylene?

Prolonged or repeated exposure of trichloroethylene causes kidney cancer. Some evidence suggests that it may be associated with an increased risks of non-Hodgkin lymphoma and, possibly, liver cancer.

How can exposures be reduced?

People who work with or near TCE should wear protective equipment and minimize exposure to the chemical.

In general, people should avoid drinking water known to be contaminated with TCE, and children should be prevented from playing in areas where the chemical has been found in the soil. Always follow instructions on product labels to minimize exposure to hazardous chemicals such as TCE.

​​​​​What is vinyl chloride?

Vinyl chloride is a colorless gas that burns easily. It does not occur naturally and must be produced industrially for its commercial uses. Vinyl chloride is used primarily to make polyvinyl chloride (PVC); PVC is used to make a variety of plastic products, including pipes, wire and cable coatings, and packaging materials. Vinyl chloride is also produced as a combustion product in tobacco smoke.

Vinyl chloride is used primarily to make PVC, a substance used in products such as pipes.

How are people exposed to vinyl chloride?

Workers at facilities where vinyl chloride is produced or used may be exposed primarily through inhalation. The general population may be exposed by inhaling contaminated air or tobacco smoke. In the environment, the highest levels of vinyl chloride are found in air around factories that produce vinyl products. If a water supply is contaminated, vinyl chloride can enter household air when the water is used for showering, cooking, or laundry.

Which cancers are associated with exposure to vinyl chloride?

Vinyl chloride exposure is associated with an increased risk of a rare form of liver cancer (hepatic angiosarcoma), as well as brain and lung cancers, lymphoma, and leukemia.

How can exposures be reduced?

The U.S. Occupational Safety & Health Administration provides information about exposure limits to vinyl chloride.