Cancer
Cancer and the Indoor Environment

Cancer and the Indoor Environment

Carcinogens
Common agents known to be human carcinogens
Treatments for cancer

Cancers are the second leading cause of death in the United States after cardiovascular disease. Cancer cells are different than normal cells in that they are bigger, divide quicker, serve no useful purpose, and exhibit uncontrolled growth and eventual spread to other parts of the body. Spread of cancer cells from their site of origin to another part of the body is called metastasis.

Cancer is not a single disease, but rather many different diseases, each affecting particular body tissues, but sharing the abnormalities of cell growth and function. Each kind of cancer will be caused by different factors. Substances that can cause cancer are called carcinogens.

Carcinogens

Public health authorities in the US have regulated indoor exposures to asbestos and radon because they are known carcinogens. Asbestos is a naturally occurring mineral fiber that was frequently used in building construction in the U.S. during the 20th century. Exposure to asbestos has been associated with lung cancer and mesothelioma, a cancer of the lining of the chest wall. Radon is a radioactive element commonly found in soils containing uranium. Because radon is a gas, it can escape the soil and enter structures (such as homes) built upon these soils. Once inside the building, the concentration of radon and related radioactive elements may increase if ventilation is inadequate. Inhalation of radioactive elements by uranium miners has been associated with increased rates of lung cancer.

In 1978, the Secretary of Health and Human Services established the National Toxicology Program (NTP) to coordinate toxicology research and testing activities within the Department; to provide information about potentially toxic chemicals to regulatory and research agencies and the public; and to strengthen the science base in toxicology. Since its inception, the NTP has become the world's leader in designing, conducting, and interpreting animal assays for toxicity and carcinogenicity. The NTP maintains a Report on Carcinogens, which lists substances that either are known to be human carcinogens or are likely to be human carcinogens, and to which a significant number of persons residing in the U.S. are exposed. The report also gives information about each of the substances and information concerning the nature of exposure and the estimated number of persons exposed to such substances.

Common Agents Known To Be Human Carcinogens

The following are some common agents that are known to be human carcinogens as listed in the 9th Report on Carcinogens:1

  • Aflatoxins

  • Asbestos

  • Benzene

  • Creosote (coal and wood)

  • Direct Black 38/Direct Blue 6: when heated to decomposition, emits toxic fumes of nitrogen oxides (NOx) and sulfur oxides (SOx)

  • Dyes that metabolize to benzidine

  • Environmental tobacco smoke

  • Radon

  • Soots

  • Vinyl chloride

In addition, in November of 1986, the state of California adopted Proposition 65 (also know as The Safe Drinking Water and Toxic Enforcement Act of 1986) in order to address growing concerns about exposures to toxic chemicals. Proposition 65 requires the listing of chemicals known or suspected of causing cancer, birth defects or other reproductive harm. This list contains over 400 carcinogens and over 200 reproductive toxicants. The list is provided to allow California consumers to make informed choices about products they purchase and to enable residents or workers to take appropriate actions to protect themselves from exposure. The list contains many kinds of chemicals, including formaldehyde, dyes, solvents, pesticides, drugs, food additives and byproducts of certain processes.2

Treatments for Cancer

  • Chemotherapy (toxic drugs to kill the cancerous cells)

  • Radiation therapy

  • Surgery

  • Bone marrow treatments

The choice of treatment for cancer usually is made by a patient in consultation with an oncologist, a physician specializing in the care of people with cancer. Treatment choices will vary for different types of cancer and for different stages of cancer.

References

  1. National Toxicology Program (NTP). 9th report on carcinogens. U.S. Department of Health and Human Services, Public Health Services, National Toxicology Program. Pursuant to section 301(b)(4) of the Public Health Service Act as amended by section 262, PL 95-622. Revised Jan. 2001.

  2. State of California environmental protection agency office of environmental health hazard assessment. Safe drinking water and toxic enforcement act of 1986. Chemicals listed effective August 4, 2000 as known to the state of California to cause cancer. Updated 8/04/2000: www.oehha.ca.gov/prop65/prop65_list/Newlist.html.