Cancer
Cancer affects millions of American families and adds billions of dollars to our nation’s annual health care bill. According to current statistics from the National Cancer Institute (NCI), over 11 million people are living with cancer in the U.S. (National Cancer Institute, Surveillance and Epidemiology End Results Program, "Data for Invasive Cancers," http://seer.cancer.gov/csr/1975_2006/) NCI estimates that 44% of men and 38% of women in the U.S. will be diagnosed with cancer at some point in their lives. (National Cancer Institute, Surveillance and Epidemiology End Results Program, “Data for Invasive Cancers,” http://seer.cancer.gov/csr/1975_2006/browse_csr.php?section=2&page=sect_02_table.11.html (accessed October 5, 2009))
Cancer is the second most common cause of death in the U.S., exceeded only by heart disease. More than 1.5 million people were diagnosed with new cases of cancer in 2009. In 2008 the direct medical costs of cancer were $93.2 billion and the overall costs were $228.1 billion. (American Cancer Society. Cancer Facts & Figures 2009 (Atlanta: American Cancer Society, 2009)) (American Cancer Society, “Costs of Cancer,” http://www.cancer.org/docroot/MIT/content/MIT_3_2X_Costs_of_cancer.asp (accessed October 5, 2009)) Medical costs for pediatric cancers alone in 1997 totaled an estimated $3.9 billion. (Philip J. Landrigan, et al., “Environmental Pollutants and Disease in American Children: Estimates of Morbidity, Mortality, and Costs for Lead Poisoning, Asthma, Cancer, and Developmental Disabilities,” Environmental Health Perspectives, 110, No. 7 (July 2002): 721–8)
Over the past two decades, the rates of some cancers rose significantly. These include:
- Kidney, liver, thyroid, esophageal and testicular cancer, as well as melanoma in men.
- Non-Hodgkin’s lymphoma, Hodgkin’s disease, melanoma and cancers of the thyroid, liver, and kidney in women.
- Childhood cancers overall, especially childhood leukemia and brain cancer (see Figure 1).
Figure 1 - Cancer Incidence and Mortality for Children Under 20
Cancer is the second most common cause of death for Americans under the age of 20. The incidence of childhood cancer increased more than 20% between 1975 and 1990. Since 1990, the incidence has remained roughly at this elevated rate. Although improved treatment options have led to a decline in the percentage of children who die from cancer, the percentage of children who are diagnosed with leukemia, brain, and other cancers has increased.
Source: U.S. EPA. America's Children and the Environment. www.epa.gov/envirohealth/children
Data: National Cancer Institute, Surveillance, Epidemiology, and End Results Program
Cancer and chemicals in the workplace
Much of what we know about chemicals and cancer comes from studies of workers who were diagnosed with cancer after exposure to chemicals in their place of employment. The U.S. Department of Health and Human Services Report on Carcinogens lists chemical hazards and vinyl chloride as known human carcinogens, and formaldehyde, trichloroethylene (TCE), and methylene chloride (dichloromethane) as likely human carcinogens. (Report on Carcinogens, Eleventh Edition; U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program) The classifications of these and the other chemicals listed in Table 1 are largely based on studies of similarly exposed and diagnosed workers. These human studies both confirm and are confirmed by animal testing and other research findings on the same chemicals.
Looking beyond workplace exposure
In the three decades since TSCA became law, it has become clear that the American people’s exposure to these and other cancer-causing chemicals is not limited to occupational settings. In an Arizona study designed to be representative of the general U.S. population, researchers found that 25% of homes contained formaldehyde levels above recommended exposure levels. (Sydney M. Gordon, et al., “Residential Environmental Measurements in the National Human Exposure Assessment Survey (NHEXAS) Pilot Study in Arizona: Preliminary Results for Pesticides and VOCs,” Journal of Exposure Analysis and Environmental Epidemiology, 9 (1999): 456–470) Formaldehyde, a known human carcinogen encountered in the workplace, is also a common indoor air contaminant because of its use in furniture, cabinets, countertops, insulation, wallpaper, paints, and paneling. Formaldehyde is found in a wide variety of consumer products such as antiseptics, medicines, cosmetics, nail polish, dishwashing liquids, fabrics and fabric softeners, shoe-care agents, carpet cleaners, glues and adhesives, lacquers, paper, coatings, and plastics. (Agency for Toxic Substances and Disease Registry, Toxicological Profile for Formaldehyde, (Washington, DC: Department of Health and Human Services, 1999))
Trichloroethylene (TCE) is another widely used chemical that is a likely human carcinogen. It is found in occupational settings as well as in consumer products such as paints and paint removers, adhesives, rug cleaners, typewriter correction fluids, metal cleaners, pepper sprays, and spot removers. (US Environmental Protection Agency, Trichloroethylene (TCE): TEACH Chemical Summary (Washington, DC: US Environmental Protection Agency, 2007))
TCE is one of the most common contaminants at toxic waste sites and is a common contaminant of groundwater aquifers. According to the Agency for Toxic Substances and Disease Registry (ATSDR), between 9% and 34% of drinking water supply sources tested in the U.S. contain some TCE. (Agency for Toxic Substances and Disease Registry, Toxicological Profile for Trichloroethylene (TCE), (Washington, DC: Department of Health and Human Services, 1997)) In one study, TCE was found in all samples of human breast milk from urban areas in the U.S. (Edo D. Pellizzari, et al., “Purgeable Organic Compounds in Mother’s Milk,” Bulletin of Environmental Contamination and Toxicology, 28, No. 23 (March1982): 322–8)
Early exposure and later cancer
Recent research has revealed how early life exposures can lead to cancer many decades later, a finding that suggests that not all carcinogens can be identified through worker exposures. Among the new studies that show the importance of the timing of exposure is a 2007 report that found a linkage between early exposure to DDT (dichloro diphenyl trichloroethane, a pesticide) and later development of breast cancer. (Barbara A. Cohn, et al., “DDT and Breast Cancer in Young Women: New Data on the Significance of Age at Exposure,” Environmental Health Perspectives, 115, No. 10 (October 2007): 1406–14)
Researchers have been investigating the relationship between DDT and breast cancer for decades. (Julia Green Brody, et al., “Environmental Pollutants and Breast Cancer: Epidemiologic Studies,” Cancer, 109, No. 12 (June 12, 2007): 2667–2711) Older studies looked at the relationship between breast cancer and the levels of DDT in women at the time of breast cancer diagnosis. Those studies did not find a strong connection between DDT and breast cancer. But in 2007, researchers published a new study of women with breast cancer that documented the DDT levels these women were exposed to when they were younger than 14 years old, through analysis of stored blood samples. The study vividly illustrates that the timing of exposure matters. Women who were exposed to DDT at ages younger than 14 had an increased risk of breast cancer. But for women exposed only after the age of 14, the increased risk from DDT was essentially zero. This study demonstrates that when children or adolescents are exposed during vulnerable periods of development, chemicals can have profound effects that are not manifest until later in life. (Barbara A. Cohn, et al., “DDT and Breast Cancer in Young Women: New Data on the Significance of Age at Exposure,” Environmental Health Perspectives, 115, No. 10 (October 2007): 1406–14)
Breast cancer rates in the U.S. increased by more than 40% between 1973 and 1998, and though in the last several years there has been a slight decline in breast cancer incidence, it remains one of the leading causes of death in women. Today, a woman’s lifetime risk of breast cancer is one in eight, up from 1 in 10 in 1973. (Janet Gray, ed, State of the Evidence: The Connection Between Breast Cancer and the Environment, (San Francisco: Breast Cancer Fund, 2008)) The human study described above has been modeled in laboratory animals, where early life exposures to low doses of chemicals have been shown to increase the risk for breast cancer by affecting mammary development and lifetime susceptibility to cancer. In laboratory studies, bisphenol A is one of the chemicals that has also been shown to cause normal breast tissue to express genes associated with a highly aggressive, and often fatal, form of breast cancer. (SH Dairkee, et al., ”Bisphenol A induces a profile of tumor aggressiveness in high-risk cells from breast cancer patients.” Cancer Research, 68, no. 7(April 1, 2008): 2076-80)
Reforming TSCA to close gaps in knowledge
While there has been a marked increase in the number of published studies on the connection between chemical exposure and cancer, researchers continue to be thwarted by all that is not known about the many chemicals that pervade daily life. Under TSCA, EPA has only required testing on 200 of the 80,000 chemicals that have been produced and used in the U.S. Most of the chemicals in use today were simply grandfathered in when TSCA became law in 1976, with no requirement that they be tested or shown to be safe. So we do not know how many other chemicals may act like DDT, leading to cancer many decades after exposure.
To be effective, TSCA reform must require chemical manufacturers to provide information on the health hazards associated with their chemicals, how they are used, and how much the public or workers could be exposed. Chemical manufacturers need to be made responsible for demonstrating the safety of their products.
Under TSCA, EPA has only required testing on 200 of the 80,000 chemicals that have been produced and used in the U.S. Most of the chemicals in use today were simply grandfathered in when TSCA became law in 1976, with no requirement that they be tested or shown to be safe.
TSCA’s failure: The asbestos example
Effective TSCA reform will give EPA the power to restrict dangerous substances like asbestos, a silicate material that has been banned in 40 other countries. (International Ban Asbestos Secretariat, “Current Asbestos Ban Restrictions,” http://ibasecretariat.org/lka_alpha_asb_ban_ 280704.php (accessed October 1, 2009)) In 1989, after a ten-year, $10 million cost-benefit analysis and the development of a 100,000 page administrative record, EPA attempted to ban asbestos. But a federal court in 1991 overturned the ban, ruling that TSCA requires that EPA not only show that a chemical is harming human health but also that the proposed restriction is the “least burdensome alternative” for eliminating “an unreasonable risk.” Since that ruling, EPA has never tried again to ban a substance using its TSCA authority. (Lowell Center for Sustainable Production, The Promise and Limits of the United States Toxic Substances Control Act, (Lowell, MA: Lowell Center for Sustainable Production, 2003)) To protect public health, TSCA reform should give EPA the power to restrict asbestos and other known human carcinogens to which people are exposed. New legislation should require EPA to assess chemicals against a health-based standard that is designed to protect the health of even the most vulnerable Americans. (This entire section is informed by the article “Environmental and Occupational Causes of Cancer: New Evidence 2005–2007.” by R.W. Clapp, M.M. Jacobs, and E.L. Loechler, published in the journal Reviews on Environmental Health, 23, no. 1 (2008): 1–47)
