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12th Report on Carcinogens

On June 10, 2011, the U.S. Department of Health and Human Services (HHS) released the 12th Report on Carcinogens (RoC)  . The Report on Carcinogens (RoC) is a science-based document that identifies chemicals and biological agents that represent cancer hazards. Eight new substances have been added in this edition of the Report on Carcinogens. The report identifies agents, substances, mixtures, or exposures in two categories: known to be a human carcinogenDictionary of Environmental Health or reasonably anticipated to be a human carcinogen. See Listing Criteria  for specific listing criteria.

A listing in the Report on Carcinogens does not by itself mean that a substance will cause cancer. Many factors, including the amount and duration of exposure, and an individual's susceptibility to a substance, affect whether a person will develop cancer.

The Report on Carcinogens and all related materials, including all 240 substance profiles, are available at 12th Report on Carcinogens (RoC)  .

The Report on Carcinogens, Twelfth Edition, is prepared by the National Toxicology Program  , an interagency program headquartered at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.

 


General Q & A

Formaldehyde (known carcinogen listing)

Styrene (reasonably anticipated listing)

Aristolochic Acids (known carcinogen listing)

Certain Glass Wool Fibers (Inhalable) (reasonably anticipated carcinogen)

 


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General Q & A

12th Edition of the Report on Carcinogens, 2011

What is the Report on Carcinogens (RoC)?  

The RoC is a scientific and public health document that provides information about the relationship between the environment and cancer. It is a congressionally mandated report (Section 301 (b) (4) of the Public Health Service Act) that identifies agents, substances, mixtures, or exposures (collectively called substances) that may potentially put people in the United States at an increased risk for cancer. Listed in the RoC are a wide range of substances, including metals, pesticides, drugs, and natural and synthetic chemicals.

 

The listings in the RoC identify a substance or exposure circumstance as a known or reasonably anticipated human carcinogen. The RoC is a hazard identification document and does not present quantitative assessments of the risks of cancer associated with exposure to these substances. Thus a listing in the RoC only indicates a potential hazard and does not estimate cancer risks to individuals associated with exposures in their daily lives.

 

The National Toxicology Program (NTP) prepares the RoC for review and approval by the Secretary of U.S. Department of Health and Human Services. The RoC can be used by regulatory agencies and others for decision making.

 

How can I access the report? 

The full Report on Carcinogens is available at 12th Report on Carcinogens (RoC)  . For each listed substance, the RoC provides information from cancer studies that support the listing, as well as information about potential sources of exposure and current federal regulations to limit exposures (substance profiles). The substance profiles for each substance are found at 12th Report on Carcinogens (RoC)  .

 

How are substances listed in the RoC? 

Agents, substances, mixtures, or exposures, collectively called substances, can be listed in the Report on Carcinogens, either as known to be a human carcinogen or as reasonably anticipated to be a human carcinogen. See Listing Criteria  for specific listing criteria.

 

Known to be a human carcinogen

This category is used primarily when there is sufficient evidence of cancer from human studies showing a cause-and-effect relationship between exposure to the substance and human cancer. Occasionally, substances are listed in this category based on human studies showing that the substance causes biological effects known to lead to the development of cancer.

 

Reasonably anticipated to be a human carcinogen

This category includes substances where there is limited evidence of cancer in humans, or sufficient evidence of cancer in experimental animals, showing a cause-and-effect relationship between exposure to the substance and cancer. Alternatively, a substance can be listed in this category, if there is evidence that it is a member of a class of substances already listed in the Report on Carcinogens or causes biological effects known to lead to the development of cancer.

 

Expert, scientific judgment, with consideration given to all relevant information, is used to review all cancer studies and to reach conclusions.

 

How does a substance get into the RoC? 

Anyone can nominate a substance to the NTP for consideration of its listing in or removal from the Report on Carcinogens by using the nomination form  .

 

A formal evaluation is conducted for the nominated substances, and candidate substances are selected to proceed through the scientific review process  .

 

What is the process for developing the 12th RoC? Did the NTP solicit public comments? 

NTP followed an established, multi-step process with multiple opportunities for public input. Public comments were solicited on the nominated substances, the draft background documents, the external expert panels’ recommendations on the substance listings, and the draft substance profiles.The public (including industry representatives) had the opportunity to submit testimony at the external expert panel meetings and the Board of Scientific Counselors meeting. The NTP website has more information about the scientific review process  for the 12th RoC.

 

Was the process used to develop the 12th RoC scientifically rigorous and have adequate external peer review? 

NTP followed an established, multi-step process with multiple opportunities for peer review to develop the 12th RoC. External expert panels conducted scientific peer-reviews of the draft background document of each substance, received public comments, and voted on the listing status of each substance, all in the setting of public meetings. The NTP Board of Scientific Counselors, a Federal advisory committee comprised of external scientific experts, peer-reviewed the draft substance profiles of each of the substances and received public comments in a public meeting.

 

What’s new in the 12th Report on Carcinogens? 

The 12th RoC includes 240 listings, some of which are classes of related chemicals or substances; 54 substances are listed as known human carcinogens, and 186 are reasonably anticipated to be human carcinogens.

 

In preparing the RoC, the NTP followed an established, multi-step process with at least 6 opportunities for public input on each substance.  The NTP used established criteria to evaluate the scientific evidence on each candidate substance under review.

 

The 12th Edition of RoC adds:

 

Known Carcinogen:

  • Aristolochic Acids
  • Formaldehyde

 

Anticipated Carcinogen:

  • Captafol
  • Cobalt-Tungsten Carbide
  • Certain Glass Wool Fibers (Inhalable)
  • o-Nitrotoluene
  • Riddelliine
  • Styrene

 

Does a listing in the RoC mean that a substance will cause cancer? 

A listing in the RoC does not by itself mean that a substance will cause cancer. Many factors, including the amount and duration of exposure, and an individual’s susceptibility to a substance,  impact whether a person will develop cancer or not.

 

For each listed substance, the RoC provides information from cancer studies that support the listing, as well as information about potential sources of exposure and current Federal regulations to limit exposures. Substance profiles for each substance are found at 12th Report on Carcinogens (RoC)  .

 

What should I do with the information in this report? 

Where possible, individuals should try to limit their exposure to the substances listed in this report.  If you have questions or concerns about current or past exposures to any of these substances, the information developed in the National Institutes of Health can help you to become better informed. Discuss these fact sheets and what you have learned with your health care providers. Another good resource is the Association of Occupational and Environmental Clinics (AOEC)  . The AOEC has a network of clinics across the country dedicated to the prevention and treatment of occupational and environmental illnesses.

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Formaldehyde (known carcinogen listing)

Image of construction site

Formaldehyde(373KB)

 

What is formaldehyde? 

Formaldehyde is a colorless, flammable, strong-smelling chemical widely used by industry to make home building products. It is a colorless gas at room temperature, or available as a liquid called formalin.

 

How is formaldehyde used? 

Formaldehyde is widely used to manufacture building materials and household products. Most formaldehyde produced in the United States is for the manufacture of resins, such as urea-formaldehyde, used to make the adhesives for pressed wood products, such as particleboard, furniture, paneling, cabinets, and other products. Formaldehyde is also commonly used as a preservative in medical laboratories, mortuaries, and consumer products, including some hair smoothing and straightening products. It is also a by-product of automobile combustion and is produced in small amounts by most living organisms, including humans.

 

How are people exposed to formaldehyde? 

People are exposed to formaldehyde in the workplace and in their home environment, but the highest levels are found in work settings where formaldehyde is used or produced. Exposure to formaldehyde can occur in numerous industries and professions, such as manufacturers of formaldehyde and formaldehyde-based resins, woodworking, and furniture making. Morticians and laboratory workers may also be exposed to formaldehyde.

 

The general population is exposed to formaldehyde by breathing contaminated indoor or outdoor air and from tobacco smoke. Automobile and other combustion sources, such as woodstoves, incinerators, refineries, forest fires, and fumes released from new construction or home-finishing products, are some of the major sources of airborne formaldehyde. Other consumer goods, including some hair smoothing and straightening products used in salons, cleaning agents, glues, and adhesives, may contain formaldehyde. Formaldehyde levels can be higher in indoor air than in outdoor air.

 

The RoC lists Formaldehyde as a known carcinogen.  Do I need to be worried that I may get cancer? 

Reducing exposure to cancer-causing agents is important to public health and the Report on Carcinogens provides important information on substances that pose a cancer risk.  A listing in the RoC does not by itself mean that a substance will cause cancer. Many factors, including the amount and duration of exposure, and an individual’s susceptibility to a substance, impact whether a person will develop cancer or not.  

 

What evidence is there that formaldehyde causes cancer? 

Human Studies:  Studies of workers exposed to high levels of formaldehyde, such as industrial workers and embalmers, found that formaldehyde causes myeloid leukemiaDictionary of Environmental Health, and rare cancers including sinonasal and nasopharyngeal cancer.

 

Animal Studies:  In laboratory animal studies, formaldehyde caused cancer primarily in the animal’s nasal cavity.

 

Mechanistic Studies: The mechanisms by which formaldehyde causes cancer are not completely understood; however, formaldehyde clearly causes genetic damage in the nasal sinus of animals. Less is known about how it causes myeloid leukemia.

 

How can I prevent exposure to this substance? 

Use lower-emitting pressed wood products, such as those that are labeled CARB (California Air Resources Board) Phase 1 or Phase 2 compliant, or made with ULEF (ultra-low-emitting formaldehyde) or NAF (no-added formaldehyde) resins. Try to learn as much as you can about the manufacturer’s products visit the store where you bought the product. 

  • Increase ventilation, particularly after bringing new sources of formaldehyde into the home.
  • Open windows and use fans to bring in fresh air.
  • Use air conditioning and dehumidifiers to maintain moderate temperature and reduce humidity levels.
  • Employers who use formaldehyde in their workplaces must follow the requirements in the Occupational Safety and Health Administration standard on formaldehyde.

 

Where can I get more information? 

 

I work in a hair salon. What can I do to limit my exposure to formaldehyde? 

The Occupational Safety and Health Administration (OSHA) and several state OSHA programs are investigating questions and complaints from hair salon owners and workers about possible formaldehyde exposure from using Brazilian Blowout and other hair smoothing products. OSHA’s April 2011 Hazard Alert provides information about OSHA's investigations, the health hazards of formaldehyde, and how to protect workers using hair smoothing products that contain or release formaldehyde. The alert can be found at http://www.osha.gov/SLTC/formaldehyde/hazard_alert.html  .

 

Is formaldehyde found in nail products on the market today? 

Formaldehyde may be present in some nail hardeners, but an ongoing FDA survey has indicated it has been removed from many of them. Low amounts of formaldehyde may be present in the nail polishes depending on the purity of the resin used in the nail polish. These formaldehyde-containing resins are used in some nail polishes, which in conjunction with nitrocellulose (the main ingredient in nail polish), form a tough, shiny and durable film on nails.

 

Is formaldehyde found in cosmetics on the market today? 

In addition to some nail hardeners, formaldehyde is used occasionally as a cosmetic preservative, primarily in cosmetics that are in brief contact with the skin or hair and are then washed off. Formaldehyde is also present at low levels when preservatives designed to slowly release formaldehyde for microbiological protection are present. Although FDA has not set a limit on formaldehyde use in cosmetic products, the Cosmetic Ingredient Review (CIR), an industry-sponsored independent panel composed of dermatologists, toxicologist, pharmacologists and chemists, has stated that cosmetic products should not contain levels of formaldehyde above 0.2%. Formaldehyde's presence in some hair smoothing products is currently being investigated by FDA as a result of recently reported complaints.

 

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Styrene (reasonably anticipated listing)

Image of machine shop worker

Styrene(248KB)

 

What is styrene? 

Styrene is a colorless, flammable liquid, which has a sweet odor and is highly volatile. It is an industrial chemical used to make polystyrene and resins, such as reinforced plastic and rubbers.

 

How is styrene used? 

Styrene is widely used to make plastics and rubber, which are used to manufacture a variety of products, such as insulation, pipes, automobile parts, printing cartridges, food containers, and carpet backing.

 

How are people exposed to styrene? 

People are exposed to styrene in the workplace and in the environment. Workers in certain occupations are potentially exposed to much higher levels of styrene than the general population.

 

For example, workers who fabricate boats, car and truck parts, tanks, and bath tubs and shower stalls with glass fiber-reinforced polyester composite plastics, may breathe in high levels of styrene in the workplace. Workers may also absorb styrene through the skin. Exposures in the workplace have decreased over time.

 

People may be exposed to styrene through breathing indoor air that has styrene vapors from building materials, photocopiers, tobacco smoke, and other products.

 

Smokers are exposed to styrene because it occurs in cigarette smoke.

 

Living near industrial facilities or hazardous waste sites is another way people may be exposed to styrene.

 

Styrene may also leach from polystyrene containers used for food products, but levels of styrene in food are very low.

 

What evidence is there that styrene causes cancer? 

Human Studies:  The limited evidence for cancer from styrene in humans is from occupational studies showing increased risks for lymphohematopoietic cancers, such as leukemia and lymphoma, and genetic damage in the white blood cells, or lymphocytes, of workers exposed to styrene. There is also some evidence for increased risk of cancer in the pancreas or esophagus among some styrene workers, but the evidence is weaker than that for lymphohematopoietic cancers.

 

Animal Studies:  Styrene caused lung tumors in several strains of mice.

 

Mechanistic Studies:  Exactly how styrene causes cancer is not fully understood, but styrene is converted, in laboratory animals and humans, to styrene–7,8–oxide, which is listed in the Report on Carcinogens as reasonably anticipated to be a human carcinogen. Styrene-7,8-oxide causes genetic damage and has been found in the blood of workers exposed to styrene.

 

If there was only “limited” evidence that styrene causes cancer in humans, shouldn’t there have been more research to make sure? 

The available evidence from studies in humans and animals supports the listing status of styrene as reasonably anticipated to be a human carcinogen.  Similar to other substances listed in the RoC, more research is needed to improve our understanding of health effects.

 

What are some things I can do to prevent exposure to styrene? 

  • Stop smoking. Styrene is found in tobacco smoke.
  • Limit children’s exposure to tobacco smoke.
  • Adhere to federal workplace regulations.

 

Workers and employers should practice good occupational health behaviors. This may include wearing protective clothing, respirators, and gloves.Work places should be well ventilated.

 

Where do I go for more information? 

 

My kids eat off polystyrene trays in the cafeteria and eat and drink from polystyrene products. Are they at risk of getting cancer? 

Styrene should not be confused with polystyrene (styrofoam). Although styrene, a liquid, is used to make polystyrene, which is a solid plastic, we do not believe that people are at risk from using polystyrene products. The listing in the RoC is specific for styrene and is based on studies of workers exposed to high levels of styrene in the workplace.

 

It is thought that styrene occurs in some foods at very low levels naturally, and if leaching of styrene into foods from polystyrene occurs, the levels of styrene remain very low.

 

Measurements of styrene in foods packaged in polystyrene show that levels in food are still orders of magnitude lower than air levels in the workplace where styrene is used.

 

The RoC listing of styrene was based on high levels of exposure such as that experienced by workers exposed to styrene in an industrial setting and it was not based on the very small amount of styrene that may possibly leach from a Styrofoam cup or plastic containers.

 

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Aristolochic Acids (known carcinogen listing)

Image of aristolochia Clematiris rendering

Aristolochic Acids(229KB)

 

What are aristolochic acids?

Aristolochic acids are a family of acids found naturally in the plants Aristolochia and Asarum.

 

How are aristolochic acids used?

Plants containing aristolochic acids are often used as herbal medicines or in other botanical products in the United States and abroad. Aristolochic acids may be found as a contaminant in herbal products used to treat a wide variety of symptoms and diseases, such as arthritis, gout, and inflammation.

 

How are people exposed to aristolochic acids?

Exposure may occur though the intentional or unintentional eating or drinking of herbal or food products that contain aristolochic acids.

In 2001, the U.S. Food and Drug Administration (FDA) advised consumers to stop using any products that may contain aristolochic acids, after seeing an increase in nephropathyhttp://www.Merriam-webster.com, or kidney disease, among users; however, products containing aristolochic acids can still be purchased on the Internet and abroad.

 

Aristolochic Acids are now listed as a known carcinogen.  Where can I get more information on Aristolochic Acids and what herbal products contain Aristolochic Acids?

Aristolochic acids are often used as herbal medicines or other botanical products in the United States and abroad to treat a wide variety of symptoms and ailments. Exposure may occur though the intentional or unintentional eating or drinking of herbal or food products that contain aristolochic acids.

In 2001, the U.S. Food and Drug Administration (FDA) advised consumers to stop using any products that may contain aristolochic acids, after seeing an increase in nephropathy, or kidney disease, among users; however, products containing aristolochic acids can still be purchased on the Internet and abroad.

See the FDA website at http://www.fda.gov/Food/RecallsOutbreaksEmergencies/SafetyAlertsAdvisories/ucm095283.htm  for a listing of products that may contain aristolochic acids.

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Certain Glass Wool Fibers (Inhalable) (reasonably anticipated carcinogen)

Image of glass wool fibers

Certain Glass Wool Fibers (Inhalable)(575KB)

 

What are glass wool fibers?

Glass wool fibers are synthetic or man-made, very small finely spun fibers of glass that form a mass resembling wool.  They are commonly used for insulation or filtration.  There is considerable variation in the properties of individual fibers within this class, depending on the manufacturing process and end use.

 

How are glass wool fibers used?

There are generally two categories of glass wool fibers that consumers might use: low-cost general-purpose fibers and premium special-purpose fibers. Most home and building insulation projects use general-purpose glass wool. Special-purpose glass fibers are used for applications, such as separating the negative and positive plates in a battery, and in high-efficiency air filters and aircraft, spacecraft, and acoustical insulation. In general, insulation fibers are less durable and less biopersistent than special-purpose fibers, and may be less likely to cause cancer than the more durable, more persistent special-purpose fibers.

 

How are people exposed to glass wool fibers?

People are primarily exposed to wool fibers by inhaling them in workplaces where products containing glass wool fibers are produced.  Individuals working on home improvement projects installing or removing insulation made of glass wool products may also be potentially exposed. However, in general, due to their low durability, most home insulation fibers are less likely to cause cancer in humans.

 

What evidence is there that certain inhalable glass wool fibers cause cancer?

Human Studies:  The available human studies are unable to determine whether exposure to glass wool fibers causes cancer.

 

Animal Studies:  There is sufficient evidence in laboratory animal studies showing that glass wool fibers, as a class, cause tumors in the animal’s lungs and at other tissue sites. However, the ability of glass wool fibers to cause cancer in animals varied depending on the types of fibers tested. Studies evaluating the relationship between fiber properties and cancer have shown that only certain fibers, specifically those biopersistent in the lung, are likely to cause cancer. Glass wool products should be tested on a case-by-case basis to determine if they are biopersistent.

 

Mechanistic Studies:  Mechanistic studies have shown that some glass wool fibers have the potential to cause damage to DNA.

 

How can I prevent exposure to this substance?

Follow safe work practices and wear appropriate protective equipment, such as long-sleeved work clothing or disposable coveralls, a respirator, safety glasses, and gloves. For more information about safe work practices and protective equipment, go to: http://www.osha.gov/SLTC/syntheticmineralfibers/index.html 

 

Does the insulation I use in my home contain glass wool fibers? Will I get cancer from using it?

In general, the fibers used in home insulation appear to be less durable and less likely to be biopersistent (remain in the lungs for long periods of time), and thus less likely to cause cancer in humans.

 

Where can I get more information?

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