Archives: Causes and Preventions

Hexavalent Chromium Compounds

Hexavalent Chromium Compounds

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

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.

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.

Selected References:

  • Agency for Toxic Substances and Disease Registry: Chromium – ToxFAQs™. Atlanta, GA: Centers for Disease Control and Prevention, 2012. Also available online. Last accessed June 7, 2024.
  • National Institute of Occupational Safety and Health. Hexavalent Chromium, Workplace Safety and Health Topics. Atlanta, GA: Centers for Disease Control and Prevention, 2013. Available online. Last accessed February 15, 2019.
  • National Toxicology Program. Chromium Hexavalent Compounds, Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Also available online. Last accessed December 5, 2022.
  • Occupational Safety and Health Administration. Hexavalent Chromium, Safety and Health Topics. Washington, DC: U.S. Department of Labor. Available online. Last accessed June 7, 2024.
  • Office of Air Quality Planning and Standards. Methods to Develop Inhalation Cancer Risk Estimates for Chromium and Nickel Compounds. Research Triangle Park, NC: U.S. Environmental Protection Agency, 2011. Also available online. Last accessed July 3, 2024.

Formaldehyde and Cancer Risk

Formaldehyde and Cancer Risk

What is formaldehyde?

Formaldehyde is a colorless, flammable, strong-smelling chemical that is used in building materials and to produce many household products. It is used in pressed-wood products, such as particleboard, plywood, and fiberboard; glues and adhesives; permanent-press fabrics; paper product coatings; and certain insulation materials. In addition, formaldehyde is commonly used as an industrial fungicide, germicide, and disinfectant, and as a preservative in mortuaries and medical laboratories. Formaldehyde also occurs naturally in the environment. It is produced in small amounts by most living organisms as part of normal metabolic processes.

How is the general population exposed to formaldehyde?

According to a 1997 report by the U.S. Consumer Product Safety Commission, formaldehyde is normally present in both indoor and outdoor air at low levels, usually less than 0.03 parts of formaldehyde per million parts of air (ppm). Materials containing formaldehyde can release formaldehyde gas or vapor into the air. One source of formaldehyde exposure in the air is automobile tailpipe emissions.

During the 1970s, urea-formaldehyde foam insulation (UFFI) was used in many homes. However, few homes are now insulated with UFFI. Homes in which UFFI was installed many years ago are not likely to have high formaldehyde levels now. Pressed-wood products containing formaldehyde resins are often a significant source of formaldehyde in homes. Other potential indoor sources of formaldehyde include cigarette smoke and the use of unvented fuel-burning appliances, such as gas stoves, wood-burning stoves, and kerosene heaters.

Industrial workers who produce formaldehyde or formaldehyde-containing products, laboratory technicians, certain health care professionals, and mortuary employees may be exposed to higher levels of formaldehyde than the general public. Exposure occurs primarily by inhaling formaldehyde gas or vapor from the air or by absorbing liquids containing formaldehyde through the skin.

What are the short-term health effects of formaldehyde exposure?

When formaldehyde is present in the air at levels exceeding 0.1 ppm, some individuals may experience adverse effects such as watery eyes; burning sensations in the eyes, nose, and throat; coughing; wheezing; nausea; and skin irritation. Some people are very sensitive to formaldehyde, whereas others have no reaction to the same level of exposure.

Can formaldehyde cause cancer?

Although the short-term health effects of formaldehyde exposure are well known, less is known about its potential long-term health effects. In 1980, laboratory studies showed that exposure to formaldehyde could cause nasal cancer in rats. This finding raised the question of whether formaldehyde exposure could also cause cancer in humans. In 1987, the U.S. Environmental Protection Agency (EPA) classified formaldehyde as a probable human carcinogen under conditions of unusually high or prolonged exposure (1). Since that time, some studies of humans have suggested that formaldehyde exposure is associated with certain types of cancer. The International Agency for Research on Cancer (IARC) classifies formaldehyde as a human carcinogen (2). In 2011, the National Toxicology Program, an interagency program of the Department of Health and Human Services, named formaldehyde as a known human carcinogen in its 12th Report on Carcinogens (3).

What have scientists learned about the relationship between formaldehyde and cancer?

Since the 1980s, the National Cancer Institute (NCI), a component of the National Institutes of Health (NIH), has conducted studies to determine whether there is an association between occupational exposure to formaldehyde and an increase in the risk of cancer. The results of this research have provided EPA and the Occupational Safety and Health Administration (OSHA) with information to evaluate the potential health effects of workplace exposure to formaldehyde.

The long-term effects of formaldehyde exposure have been evaluated in epidemiologic studies (studies that attempt to uncover the patterns and causes of disease in groups of people). One type of epidemiologic study is called a cohort study. A cohort is a group of people who may vary in their exposure to a particular factor, such as formaldehyde, and are followed over time to see whether they develop a disease. Another kind of epidemiologic study is called a case-control study. Case-control studies begin with people who are diagnosed as having a disease (cases) and compare them to people without the disease (controls), trying to identify differences in factors, such as exposure to formaldehyde, that might explain why the cases developed the disease but the controls did not.

Several NCI surveys of professionals who are potentially exposed to formaldehyde in their work, such as anatomists and embalmers, have suggested that these individuals are at an increased risk of leukemia and brain cancer compared with the general population. However, specific work practices and exposures were not characterized in these studies. An NCI case-control study among funeral industry workers that characterized exposure to formaldehyde also found an association between increasing formaldehyde exposure and mortality from myeloid leukemia (4). For this study, carried out among funeral industry workers who had died between 1960 and 1986, researchers compared those who had died from hematopoietic and lymphatic cancers and brain tumors with those who died from other causes. (Hematopoietic or hematologic cancers such as leukemia develop in the blood or bone marrow. Lymphatic cancers develop in the tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases.) This analysis showed that those who had performed the most embalming and those with the highest estimated formaldehyde exposure had the greatest risk of myeloid leukemia. There was no association with other cancers of the hematopoietic and lymphatic systems or with brain cancer.

A number of cohort studies involving workers exposed to formaldehyde have recently been completed. One study, conducted by NCI, looked at 25,619 workers in industries with the potential for occupational formaldehyde exposure and estimated each worker’s exposure to the chemical while at work (5). The results showed an increased risk of death due to leukemia, particularly myeloid leukemia, among workers exposed to formaldehyde. This risk was associated with increasing peak and average levels of exposure, as well as with the duration of exposure, but it was not associated with cumulative exposure. An additional 10 years of data on the same workers were used in a follow-up study published in 2009 (6). This analysis continued to show a possible link between formaldehyde exposure and cancers of the hematopoietic and lymphatic systems, particularly myeloid leukemia. As in the initial study, the risk was highest earlier in the follow-up period. Risks declined steadily over time, such that the cumulative excess risk of myeloid leukemia was no longer statistically significant at the end of the follow-up period. The researchers noted that similar patterns of risks over time had been seen for other agents known to cause leukemia.

A cohort study of 11,039 textile workers performed by the National Institute for Occupational Safety and Health (NIOSH) also found an association between the duration of exposure to formaldehyde and leukemia deaths (7). However, the evidence remains mixed because a cohort study of 14,014 British industry workers found no association between formaldehyde exposure and leukemia deaths (8).

Formaldehyde undergoes rapid chemical changes immediately after absorption. Therefore, some scientists think that formaldehyde is unlikely to have effects at sites other than the upper respiratory tract. However, some laboratory studies suggest that formaldehyde may affect the lymphatic and hematopoietic systems. Based on both the epidemiologic data from cohort and case-control studies and the experimental data from laboratory research, NCI investigators have concluded that exposure to formaldehyde may cause leukemia, particularly myeloid leukemia, in humans.

In addition, several case-control studies, as well as analysis of the large NCI industrial cohort (6), have found an association between formaldehyde exposure and nasopharyngeal cancer, although some other studies have not. Data from extended follow-up of the NCI cohort found that the excess of nasopharyngeal cancer observed in the earlier report persisted (9).

Earlier analysis of the NCI cohort found increased lung cancer deaths among industrial workers compared with the general U.S. population. However, the rate of lung cancer deaths did not increase with higher levels of formaldehyde exposure. This observation led the researchers to conclude that factors other than formaldehyde exposure might have caused the increased deaths. The most recent data on lung cancer from the cohort study did not find any relationship between formaldehyde exposure and lung cancer mortality.

What has been done to protect workers from formaldehyde?

In 1987, OSHA established a Federal standard that reduced the amount of formaldehyde to which workers can be exposed over an 8-hour workday from 3 ppm to 1 ppm. In May 1992, the standard was amended, and the formaldehyde exposure limit was further reduced to 0.75 ppm.

How can people limit formaldehyde exposure in their homes?

The EPA recommends the use of “exterior-grade” pressed-wood products to limit formaldehyde exposure in the home. These products emit less formaldehyde because they contain phenol resins, not urea resins. (Pressed-wood products include plywood, paneling, particleboard, and fiberboard and are not the same as pressure-treated wood products, which contain chemical preservatives and are intended for outdoor use.) Before purchasing pressed-wood products, including building materials, cabinetry, and furniture, buyers should ask about the formaldehyde content of these products. Formaldehyde levels in homes can also be reduced by ensuring adequate ventilation, moderate temperatures, and reduced humidity levels through the use of air conditioners and dehumidifiers.

Where can people find more information about formaldehyde?

The following organizations can provide additional resources that readers may find helpful:

The EPA offers information about the use of formaldehyde in building materials and household products. The EPA can be contacted at:

U.S. Environmental Protection Agency
Office of Radiation and Indoor Air
Indoor Environments Division
Mail Code 6609J
1200 Pennsylvania Avenue, NW.
Washington, DC 20460
202–554–1404 (EPA Toxic Substance Control Act (TCSA) Assistance Line)
http://www.epa.gov/iaq/formalde.html

The U.S. Consumer Product Safety Commission (CPSC) has information about household products that contain formaldehyde. CPSC can be contacted at:

U.S. Consumer Product Safety Commission
4330 East West Highway
Bethesda, MD 20814
1–800–638–2772 (1–800–638–CPSC)
301–595–7054 (TTY)
http://www.cpsc.gov

The U.S. Food and Drug Administration (FDA) maintains information about cosmetics and drugs that contain formaldehyde. FDA can be contacted at:

U.S. Food and Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993–0002
1–888–463–6332 (1–888–INFO–FDA)
http://www.fda.gov

The Federal Emergency Management Agency (FEMA) has information about formaldehyde exposure levels in mobile homes and trailers supplied by FEMA after Hurricane Katrina. FEMA can be contacted at:

Federal Emergency Management Agency
Post Office Box 10055
Hyattsville, MD 20782–7055
1–800–621–3362 (1–800–621–FEMA)
http://www.fema.gov

The Occupational Safety and Health Administration (OSHA) has information about occupational exposure limits for formaldehyde. OSHA can be contacted at:

U.S. Department of Labor
Occupational Safety and Health Administration
200 Constitution Avenue
Washington, DC 20210
1–800–321–6742 (1–800–321–OSHA)
http://www.osha.gov

The National Toxicology Program (NTP) is an interagency program of the Department of Health and Human Services that was created to coordinate toxicology testing programs within the federal government; to develop and validate improved testing methods; and to provide information about potentially toxic chemicals to health, regulatory, and research agencies, scientific and medical communities, and the public. NTP is headquartered at the National Institute of Environmental Health Sciences, which is part of NIH. NTP can be contacted at:

National Toxicology Program
111 TW Alexander Drive
Building 101
Research Triangle Park, NC 27709
919–541–0530
http://ntp.niehs.nih.gov

Formaldehyde

Formaldehyde

Formaldehyde is commonly used as a preservative.

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.

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.

Selected References:

  • National Institute of Occupational Safety and Health. Formaldehyde, Workplace Safety and Health Topics. Atlanta, GA: Centers for Disease Control and Prevention. Available online. Last accessed August 6, 2024.
  • National Toxicology Program. Formaldehyde, Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Also available online. Last accessed December 5, 2022.
  • U.S. Environmental Protection Agency. Formaldehyde. Washington, DC: U.S. Environmental Protection Agency, 2013. Available online. Last accessed February 14, 2019.

Cadmium

Cadmium

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

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.

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.

Selected References:

  • Agency for Toxic Substances and Disease Registry. Toxic Substances Portal – Cadmium. Atlanta, GA: Centers for Disease Control and Prevention, 2014. Available online. Last accessed June 7, 2024.
  • National Institute of Occupational Safety and Health. Cadmium Dust, NIOSH Pocket Guide to Chemical Hazards. Atlanta, GA: Centers for Disease Control and Prevention, 2010. Available online. Last accessed February 1, 2019.
  • National Toxicology Program. Cadmium and Cadmium Compounds, Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Available online. Last accessed December 5, 2022.
  • U.S. Environmental Protection Agency. Basic Information about Cadmium in Drinking Water. Washington, DC: U.S. Environmental Protection Agency, 2013. Available online. Last accessed June 7, 2024.

Coal Tar and Coal-Tar Pitch

Coal Tar and Coal-Tar Pitch

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

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.

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.

Selected References:

  • National Toxicology Program. Coal Tars and Coal-Tar Pitches, Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Also available online. Last accessed December 5, 2022.
  • National Water-Quality Assessment Program. Frequently Asked Questions—Parking-Lot Sealcoat: A Major Source of PAHs in Urban and Suburban Environments. Reston, VA: U.S. Geological Survey, 2014. Available online. Last accessed June 7, 2024.
  • Occupational Safety and Health Administration. Coal Tar Pitch Volatiles, Safety and Health Topics. Washington, DC: U.S. Department of Labor. Available online. Last accessed June 7, 2024.
  • Office of Water. Stormwater Best Management Practice: Coal-Tar Sealcoat, Polycyclic Aromatic Hydrocarbons, and Stormwater Pollution. Washington, DC: U.S. Environmental Protection Agency, 2012. Also available online. Last accessed June 7, 2024.

1,3-Butadiene

1,3-Butadiene

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

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.

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.

Selected References:

  • Health Effects Notebook for Hazardous Air Pollutants. 1,3-Butadiene Fact Sheet. Washington, DC: U.S. Environmental Protection Agency, 2009. Available online. Last accessed June 5, 2024.
  • International Agency for Research on Cancer. 1,3 Butadiene, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 97. Lyon, France: World Health Organization, 2012. Also available online. Last accessed August 6, 2024.
  • National Toxicology Program. 1,3 Butadiene, Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Also available online. Last accessed December 5, 2022.
  • Occupational Safety and Health Administration. 1,3-Butadiene, Safety and Health Topics. Washington, DC: U.S. Department of Labor. Available online. Last accessed January 31, 2019.

Coke Oven Emissions

Coke Oven Emissions

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

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.

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.

Selected References:

  • Health Effects Notebook for Hazardous Air Pollutants. Coke Oven Emissions Fact Sheet. Washington, DC: U.S. Environmental Protection Agency, 2013. Available online. Last accessed February 1, 2019.
  • International Agency for Research on Cancer. Coke Production, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 100F. Lyon, France: World Health Organization, 2012. Available online. Last accessed June 10, 2024.
  • National Institute of Occupational Safety and Health. Coke Oven Emissions, NIOSH Pocket Guide to Chemical Hazards. Atlanta, GA: Centers for Disease Control and Prevention, 2010. Available online. Last accessed February 1, 2019.
  • National Toxicology Program. Coke-Oven Emissions, Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Available online. Last accessed December 5, 2022.

Crystalline Silica

Crystalline Silica

Quartz is the most common form of crystalline silica.

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.

How can exposures be reduced?

The Mine Safety and Health Administration and the U.S. Occupational Safety & Health Administration (OSHA) have regulations related to silica. For example, OSHA has a fact sheet on Control of Silica Dust in Construction: Handheld Power Saws.

Selected References:

  • International Agency for Research on Cancer. Silica Dust, Crystalline, In the Form of Quartz or Cristobalite, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 100C. Lyon, France: World Health Organization, 2012. Available online. Last accessed December 13, 2023.
  • National Institute for Occupational Safety and Health. Preventing Silicosis and Deaths in Construction Workers. Atlanta, GA: Centers for Disease Control and Prevention, 2014. Available online. Last accessed December 13, 2023.
  • National Institute for Occupational Safety and Health. Silica, Crystalline (as respirable dust), NIOSH Pocket Guide to Chemical Hazards. Atlanta, GA: Centers for Disease Control and Prevention, 2010. Available online. Last accessed December 13, 2023.
  • National Toxicology Program. Silica, Crystalline (Respirable Size), Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Available online. Last accessed December 5, 2022.
  • Occupational Safety and Health Administration. Silica, Crystalline. Washington, DC: U.S. Department of Labor. Available online. Last accessed December 13, 2023.

Beryllium

Beryllium

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

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.

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.

How can exposure be reduced?

The U.S. Occupational Safety & Health Administration has information about preventing adverse health effects from exposure to beryllium on the job.

Selected References:

  • Agency for Toxic Substances and Disease Registry. Toxic Substances Portal – Beryllium. Atlanta, GA: Centers for Disease Control and Prevention, 2014. Available online. Last accessed June 5, 2024.
  • International Agency for Research on Cancer. Beryllium and Beryllium Compounds, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 100C. Lyon, France: World Health Organization, 2012. Available online. Last accessed August 6, 2024.
  • National Institute of Occupational Safety and Health. Beryllium and Beryllium Compounds, NIOSH Pocket Guide to Chemical Hazards. Atlanta, GA: Centers for Disease Control and Prevention, 2010. Available online. Last accessed January 31, 2019.
  • National Toxicology Program. Beryllium and Beryllium Compounds, Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Available online. Last accessed December 8, 2022.

Asbestos Exposure and Cancer Risk

Asbestos Exposure and Cancer Risk

What is asbestos?

Asbestos is the name given to six minerals that occur naturally in the environment as bundles of fibers that can be separated into thin, durable threads for use in commercial and industrial applications. These fibers are resistant to heat, fire, and chemicals and do not conduct electricity. For these reasons, asbestos has been used widely in many industries. Additional asbestos-like minerals are found in the natural environment, including erionite.

Chemically, asbestos minerals are silicate compounds, meaning they contain atoms of silicon and oxygen in their molecular structure.

Asbestos minerals are divided into two major groups: Serpentine asbestos and amphibole asbestos. Serpentine asbestos includes the mineral chrysotile, which has long, curly fibers that can be woven. Chrysotile asbestos is the form that has been used most widely in commercial applications. Amphibole asbestos includes the minerals actinolite, tremolite, anthophyllite, crocidolite, and amosite. Amphibole asbestos has straight, needle-like fibers that are more brittle than those of serpentine asbestos and are more limited in their ability to be fabricated (1, 2).

How is asbestos used?

Asbestos has been mined and used commercially in North America since the late 1800s. Its use increased greatly during World War II (3, 4). Since then, asbestos has been used in many industries. For example, the building and construction industries have used it for strengthening cement and plastics as well as for insulation, roofing, fireproofing, and sound absorption. The shipbuilding industry has used asbestos to insulate boilers, steam pipes, and hot water pipes. The automotive industry uses asbestos in vehicle brake shoes and clutch pads. Asbestos has also been used in ceiling and floor tiles; paints, coatings, and adhesives; and plastics. In addition, asbestos has been found in vermiculite-containing garden products and some talc-containing crayons.

In the late 1970s, the U.S. Consumer Product Safety Commission (CPSC) banned the use of asbestos in wallboard patching compounds and gas fireplaces because the asbestos fibers in these products could be released into the environment during use. In addition, manufacturers of electric hairdryers voluntarily stopped using asbestos in their products in 1979. In 1989, the U.S. Environmental Protection Agency (EPA) banned all new uses of asbestos; however, uses developed before 1989 are still allowed. The EPA also established regulations that require school systems to inspect buildings for the presence of damaged asbestos and to eliminate or reduce asbestos exposure to occupants by removing the asbestos or encasing it (2).

In June 2000, the CPSC concluded that the risk of children’s exposure to asbestos fibers in crayons was extremely low.  U.S. manufacturers of these crayons agreed to eliminate talc from their products.

In August 2000, the EPA conducted a series of tests to evaluate the risk for consumers of adverse health effects associated with exposure to asbestos-contaminated vermiculite. The EPA concluded that exposure to asbestos from some vermiculite products poses only a minimal health risk. The EPA recommended that consumers reduce the low risk associated with the occasional use of vermiculite during gardening activities by limiting the amount of dust produced during vermiculite use. Specifically, the EPA suggested that consumers use vermiculite outdoors or in a well-ventilated area; keep vermiculite damp while using it; avoid bringing dust from vermiculite into the home on clothing; and use premixed potting soil, which is less likely to generate dust (2).

The regulations described above and other actions, coupled with widespread public concern about the health hazards of asbestos, have resulted in a significant annual decline in the U.S. use of asbestos. Domestic consumption of asbestos amounted to about 803,000 metric tons in 1973, but it had dropped to about 360 metric tons by 2015 (3, 5).

What are the health hazards of exposure to asbestos?

People may be exposed to asbestos in their workplace, their communities, or their homes. 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, these fibers can accumulate and cause scarring and inflammation, which can affect breathing and lead to serious health problems (6).

Asbestos has been classified as a known human carcinogen (a substance that causes cancer) by the U.S. Department of Health and Human Services (HHS), the U.S. Environmental Protection Agency (EPA), and the International Agency for Research on Cancer (IARC) (2, 3, 7, 8). According to IARC, there is sufficient evidence that asbestos causes mesothelioma (a relatively rare cancer of the thin membranes that line the chest and abdomen), and cancers of the lung, larynx, and ovary (8). In fact, it is thought that most mesotheliomas are due to asbestos exposure (9). There is limited evidence that asbestos exposure is linked to increased risks of cancers of the stomach, pharynx, and colorectum (8).

Asbestos exposure may also increase the risk of asbestosis (an inflammatory condition affecting the lungs that can cause shortness of breath, coughing, and permanent lung damage) and other nonmalignant lung and pleural disorders, including pleural plaques (changes in the membranes surrounding the lung), pleural thickening, and benign pleural effusions (abnormal collections of fluid between the thin layers of tissue lining the lungs and the wall of the chest cavity). Although pleural plaques are not precursors to lung cancer, evidence suggests that people with pleural disease caused by exposure to asbestos may be at increased risk for lung cancer (2, 10).

Erionite has also been classified as a known human carcinogen by IARC (8) and by HHS (3). It is not currently regulated by the EPA.

Everyone is exposed to asbestos at some time during their life. Low levels of asbestos are present in the air, water, and soil. However, most people do not become ill from their exposure. People who become ill from asbestos are usually those who are exposed to it on a regular basis, most often in a job where they work directly with the material or through substantial environmental contact.

Since the early 1940s, millions of American workers have been exposed to asbestos. Health hazards from asbestos fibers have been recognized in workers exposed in the shipbuilding trades, asbestos mining and milling, manufacturing of asbestos textiles and other asbestos products, insulation work in the construction and building trades, and a variety of other trades. Demolition workers, drywall removers, asbestos removal workers, firefighters, and automobile workers also may be exposed to asbestos fibers. Studies evaluating the cancer risk experienced by automobile mechanics exposed to asbestos through brake repair are limited, but the overall evidence suggests there is no safe level of asbestos exposure (3, 8). As a result of government regulations and improved work practices, today’s workers (those without previous exposure) are likely to face smaller risks than did those exposed in the past.

Individuals involved in the rescue, recovery, and cleanup at the site of the September 11, 2001, attacks on the World Trade Center (WTC) in New York City are another group at risk of developing an asbestos-related disease. Because asbestos was used in the construction of the North Tower of the WTC, when the building was attacked, hundreds of tons of asbestos were released into the atmosphere. Those at greatest risk include firefighters, police officers, paramedics, construction workers, and volunteers who worked in the rubble at Ground Zero. Others at risk include residents in close proximity to the WTC towers and those who attended schools nearby. These individuals will need to be followed to determine the long-term health consequences of their exposure (11). However, it is important to note that any symptoms these individuals experience may be related to exposure to debris components other than asbestos.

Although it is clear that the health risks from asbestos exposure increase with heavier exposure and longer exposure time, investigators have found asbestos-related diseases in individuals with only brief exposures. Generally, those who develop asbestos-related diseases show no signs of illness for a long time after exposure. It can take from 10 to 40 years or more for symptoms of an asbestos-related condition to appear (2).

There is some evidence that family members of workers heavily exposed to asbestos face an increased risk of developing mesothelioma (12). This risk is thought to result from exposure to asbestos fibers brought into the home on the shoes, clothing, skin, and hair of workers. To decrease these exposures, Federal law regulates workplace practices to limit the possibility of asbestos being brought home in this way. Some employees may be required to shower and change their clothes before they leave work, store their street clothes in a separate area of the workplace, or wash their work clothes at home separately from other clothes (2).

Cases of mesothelioma have also been seen in individuals without occupational asbestos exposure who live close to asbestos mines (12).

Several factors can help to determine how asbestos exposure affects an individual, including:

  • Dose (how much asbestos an individual was exposed to)
  • Duration (how long an individual was exposed)
  • Size, shape, and chemical makeup of the asbestos fibers
  • Source of the exposure
  • Individual risk factors, such as smoking and pre-existing lung disease
  • Genetic factors, such as having a germline mutation in BAP1 (13)

Although all forms of asbestos are considered hazardous, different types of asbestos fibers may be associated with different health risks. For example, the results of several studies suggest that amphibole forms of asbestos may be more harmful than chrysotile, particularly for mesothelioma risk, because they tend to stay in the lungs for a longer period of time (1, 2).

How does smoking affect risk?

Many studies have shown that the combination of smoking and asbestos exposure is particularly hazardous. Smokers who are also exposed to asbestos have a risk of developing lung cancer that is greater than the individual risks from asbestos and smoking added together (3, 6). There is evidence that quitting smoking will reduce the risk of lung cancer among asbestos-exposed workers (4). Smoking combined with asbestos exposure does not appear to increase the risk of mesothelioma (10). However, people who were exposed to asbestos on the job at any time during their life or who suspect they may have been exposed should not smoke. 

Individuals who have been exposed (or suspect they have been exposed) to asbestos fibers on the job, through the environment, or at home via a family contact should inform their doctor about their exposure history and whether or not they experience any symptoms. The symptoms of asbestos-related diseases may not become apparent for many decades after the exposure. It is particularly important to check with a doctor if any of the following symptoms develop:

  • Shortness of breath, wheezing, or hoarseness
  • A persistent cough that gets worse over time
  • Blood in the sputum (fluid) coughed up from the lungs
  • Pain or tightening in the chest
  • Difficulty swallowing
  • Swelling of the neck or face
  • Loss of appetite
  • Weight loss
  • Fatigue or anemia

A thorough physical examination, including a chest x-ray and lung function tests, may be recommended. The chest x-ray is currently the most common tool used to detect asbestos-related diseases. Although chest x-rays cannot detect asbestos fibers in the lungs, they can help identify any early signs of lung disease resulting from asbestos exposure (2).

A lung biopsy, which detects microscopic asbestos fibers in pieces of lung tissue removed by surgery, is the most reliable test to confirm exposure to asbestos (2). A bronchoscopy is a less invasive test than a biopsy and detects asbestos fibers in material that is rinsed out of the lungs (2). It is important to note that these procedures cannot determine how much asbestos an individual may have been exposed to or whether disease will develop. Asbestos fibers can also be detected in urine, mucus, and feces, but these tests are not reliable for determining how much asbestos may be in an individual’s lungs (2).

How can workers protect themselves from asbestos exposure?

The Occupational Safety and Health Administration (OSHA) is a component of the U.S. Department of Labor (DOL) and is the Federal agency responsible for health and safety regulations in maritime, construction, manufacturing, and service workplaces. OSHA established regulations dealing with asbestos exposure on the job, specifically in construction work, shipyards, and general industry, that employers are required to follow. In addition, the Mine Safety and Health Administration (MSHA), another component of DOL, enforces regulations related to mine safety. Workers should use all protective equipment provided by their employers and follow recommended workplace practices and safety procedures. For example, National Institute for Occupational Safety and Health (NIOSH)-approved respirators that fit properly should be worn by workers when required.

Workers who are concerned about asbestos exposure in the workplace should discuss the situation with other employees, their employee health and safety representative, and their employers. If necessary, OSHA can provide more information or make an inspection. Information about regional offices can also be found on OSHA’s website at https://www.osha.gov/html/RAmap.html.

More information about asbestos is available on OSHA’s Asbestos page, which has links to information about asbestos in the workplace, including what OSHA standards apply, the hazards of asbestos, evaluating asbestos exposure, and controls used to protect workers. OSHA’s national office can be contacted at:

Office of Public Affairs
Occupational Safety and Health Administration
U.S. Department of Labor
202–693–1999
1–800–321–6742 (1–800–321–OSHA)
1–877–889–5627 (TTY)
https://www.osha.gov/workers (workers’ page)

Mine workers can contact MSHA at:

Office of Public Affairs
Mine Safety and Health Administration
U.S. Department of Labor
202–693–9400
https://www.msha.gov
https://egov.msha.gov/HazardousConditionComplaint.aspx  (Hazardous Condition Complaint)

The National Institute for Occupational Safety and Health (NIOSH), which is part of the Centers for Disease Control and Prevention (CDC), is another Federal agency that is concerned with asbestos exposure in the workplace. NIOSH conducts asbestos-related research, evaluates work sites for possible health hazards, and makes exposure control recommendations. In addition, NIOSH distributes publications on the health effects of asbestos exposure and can suggest additional sources of information. NIOSH can be contacted at:

Education and Information Division
Information Resources Branch
National Institute for Occupational Safety and Health
1–800–CDC–INFO (1–800–232–4636)
https://www.cdc.gov/niosh
 

Some people with asbestos-related illness may be eligible for Medicare coverage. Information about benefits is available from Medicare’s Regional Offices, located in 10 major cities across the United States and serving specific geographic areas. The Regional Offices serve as the agency’s initial point of contact for beneficiaries, health care providers, state and local governments, and the general public. General information about Medicare is available by calling toll-free 1–800–633–4227 (1–800–MEDICARE) or by visiting the Medicare website.

People with occupational asbestos-related diseases also may qualify for financial help, including medical payments, under state workers’ compensation laws. Because eligibility requirements vary from state to state, workers employed by private companies or by state and local government agencies should contact their state workers’ compensation board. Contact information for state workers’ compensation officials may be found at the U.S. Department of Labor (DOL) website.

If exposure occurred during employment with a Federal agency, medical expenses and other compensation may be covered by the Federal Employees’ Compensation Program, which is administered by the DOL Employment Standards Administration’s Office of Workers’ Compensation Programs. This program provides workers’ compensation benefits to Federal (civilian) employees for employment-related injuries and diseases. Benefits include wage replacement, payment for medical care, and, where necessary, medical and vocational rehabilitation assistance in returning to work. Benefits may also be provided to dependents if the injury or disease causes the employee’s death.

In addition, the Longshore and Harbor Workers’ Compensation Program provides benefits to longshoremen, harbor workers, other maritime workers, and other classes of private industry workers who are injured during the course of employment or suffer from diseases caused or worsened by conditions of employment. Information about eligibility and how to file a claim for benefits under either of these programs is available from:

Office of Workers’ Compensation Programs
Employment Standards Administration
U.S. Department of Labor
1–866–692–7487 (1–866–OWCPIVR)
202–693–0040 (Federal Employees’ Compensation Program)
202–693–0038 (Longshore and Harbor Workers’ Compensation Program)
https://www.dol.gov/agencies/owcp

Eligible veterans may receive health care at a Department of Veterans Affairs (VA) Medical Center for an asbestos-related disease. Veterans can receive treatment for service-connected and nonservice-connected medical conditions. Information about eligibility and benefits is available from the VA Health Benefits Service Center at 1–877–222–8387 (1–877–222–VETS) or on the VA website.

The organizations listed below can provide more information about asbestos exposure.

The Agency for Toxic Substances and Disease Registry (ATSDR) is the principal Federal agency responsible for evaluating the human health effects of exposure to hazardous substances. This agency works in close collaboration with local, state, and other Federal agencies, with tribal governments, and with communities and local health care providers to help prevent or reduce harmful human health effects from exposure to hazardous substances. The ATSDR provides information about asbestos and where to find occupational and environmental health clinics. The ATSDR can be contacted at:

Agency for Toxic Substances and Disease Registry
1–800–232–4636 (1–800–CDC–INFO)
1–888–232–6348 (TTY)
https://www.atsdr.cdc.gov/

The U.S. Environmental Protection Agency (EPA) regulates the general public’s exposure to asbestos in buildings, drinking water, and the environment. The EPA offers a Toxic Substances Control Act (TSCA) Hotline and an Asbestos Ombudsman. The TSCA Hotline provides technical assistance and information about asbestos programs implemented under the TSCA, which include the Asbestos School Hazard Abatement Act and the Asbestos Hazard Emergency Response Act. The Asbestos Ombudsman focuses on asbestos in schools and handles questions and complaints. Both the TSCA Hotline and the Asbestos Ombudsman can provide publications on a number of topics, particularly on controlling asbestos exposure in schools and other buildings. The Ombudsman operates a toll-free hotline for small businesses, trade associations, and others seeking free, confidential help.

The EPA website includes a list of EPA state asbestos contacts. In addition, EPA’s Asbestos page provides links to information about asbestos and its health effects, including suggestions for homeowners who suspect asbestos in their homes, and laws and regulations applicable to asbestos. Questions may be directed to:

U.S. Environmental Protection Agency
202–554–1404 (TSCA Hotline)
1–800–368–5888 (Asbestos Ombudsman)
https://www.epa.gov/asbestos

Another EPA resource that may be of interest is the brochure titled Current Best Practices for Preventing Asbestos Exposure Among Brake and Clutch Repair Workers. Released in April 2007, this brochure includes work practices for both automotive professionals and home mechanics that may be used to avoid asbestos exposure. It also summarizes existing OSHA regulatory requirements for professional auto mechanics.

The U.S. Consumer Product Safety Commission (CPSC) is responsible for protecting the public from unreasonable risks of serious injury or death from more than 15,000 types of consumer products, including asbestos, under the agency’s jurisdiction. The CPSC maintains a toll-free 24-hour hotline where callers can obtain product safety and other agency information and report unsafe products. In addition, CPSC publications provide guidelines for repairing and removing asbestos, and general information about asbestos in the home. CPSC can be contacted at:

Office of Information and Public Affairs
U.S. Consumer Product Safety Commission
(301) 504-7923 (M-F 8 am – 4:30 pm ET)
1–800–638–2772 (Hotline)
301-595-7054 (TTY)
https://www.cpsc.gov/

Individuals can also contact their local or state health department with questions or concerns about asbestos.