Environment and Breast Cancer: Science Review
We assigned each chemical into one of the following groups based on its major sources and uses: industrial chemicals, chlorinated solvents, products of combustion, pesticides, dyes, radiation and drinking water disinfection, pharmaceuticals, hormones, natural products, and research chemicals.Product of combustion
Found in consumer products
"Likely" indicates that the chemical is contained in consumer products or traces of the chemical are present in products, including food and water, resulting in likely exposure for the general population. For some chemicals marked as "likely," consumer product uses have been discontinued, and this will be indicated in the "Use in Consumer Products" field.Not likely
Food additive in US
Chemicals are classified as "Listed" or "Not listed" in the Everything Added to Food in the United States database developed by the US Food and Drug Administration.(22)Not listed
California Proposition 65
Chemicals are labeled "Listed" or "Not listed" based on the Proposition 65 list of chemicals updated on May 27, 2005. Listed chemicals are "chemicals known by the State of California to cause cancer or reproductive toxicity"(19).Listed
Chemicals classified as "Likely" air pollutants are those likely to be found in indoor or outdoor air, including products of combustion and industrial chemicals that may offgas from consumer products, leading to human exposure.Likely
Current High Production Volume chemical
Chemicals are classified "Yes" or "No," based on 2002 production volume information submitted to the US EPA: "Yes" for >1 million pounds produced; "No" for < 1 million pounds produced. Some past production volumes are referenced, where appropriate, in the HPV comment column (20). In addition, Scorecard.org is referenced and noted in the HPV comment column when it was inconsistent with current production volume information obtained from US EPA (21).No
Production volume information
Production volume information is from the US EPA database on non-confidential production volume information submitted by companies for chemicals under the 1986-2002 Inventory Update Rule (IUR) using the most updated (2002) values (20). The Inventory Update Rule requires the submission of basic production data every four years on chemical substances manufactured (including imported) for commercial purposes in amounts of 25,000 pounds or more at a single site. Out of over 80,000 chemicals on the TSCA Chemical Substances Inventory, reports are required for approximately 9,000 substances. For those substances with annual volumes of 300,000 lbs or more per site, reporters also submit chemical processing and use information.--
General population exposure
This field includes information describing pathways of exposure for the general population obtained from a variety of sources including: IARC Monographs (9), NTP 11th ROC on Carcinogens (4), NTP Study Reports and Abstracts (3), Hazardous Substance Database (10), and other sources located through use of the Google search engine.Exposure occurs primarily through the smoking of tobacco, inhalation of polluted air and by ingestion of food and water contaminated by combustion effluents (IARC 1983 vol.:32 p.211) (11th ROC).
Use in consumer products
Summaries of chemical use in consumer products were developed from information found in US EPA SRD (11), NLM HPD (12), and Scorecard (12). Major uses were taken from IARC Monographs (9), NTP 11th ROC (4), NTP Study Reports (3), HSDB (10), and PAN Pesticides Database (13). If a chemical could not be found in these sources, we searched ToxNet (14), PubChem (15), and The Merck Index (16), and conducted searches by both name and CAS No. using Google.No consumer products listed in SRD, HPD, or Scorecard. Benzo[a]pyrene is found in gasoline and diesel exhaust, cigarette smoke and smoke condensate, pyrolysis products of carbohydrates, amino acids, fatty acids, coal tar and coal tar pitch, soot and smoke, petroleum asphalt, creosote oil, shale oil, and commercial solvents (11th ROC). Used as a research chemical (HSDB).
Occupational exposure to women
We extracted the total number of potentially exposed workers and the number of potentially exposed female workers from the National Occupational Exposure Survey (NOES) 1981-1983; we listed specific industry classifications if >5,000 women were potentially exposed in that industry. Note: NOES does not include farm workers.NOES 1981-1983-Total exposed: 896 Females exposed: 299 Occupational situations involving heating organic material may potentially result in exposure to this compound through inhalation of air particulate matter and dermal contact with combustion products (HSDB).
US EPA cancer classification
The US EPA Weight of Evidence Characterization of the chemical’s carcinogenic potential is listed: Group A: Carcinogenic to humans; Group B: Probably carcinogenic to humans. Group C: Possibly carcinogenic to humans. Group D: Not classifiable as to human carcinogenicity. Group E: Evidence of non-carcinogenicity for humans. NA: Not evaluated by US EPA (17).B2: Probably Carcinogenic to Humans, inadequate evidence
US EPA Weight of Evidence narrative
US EPA narrative statement of overall weight of evidence for carcinogenicity (animal, human, and other supportive data).Human data specifically linking benzo[a]pyrene (BAP) to a carcinogenic effect are lacking. There are, however, multiple animal studies in many species demonstrating BAP to be carcinogenic following administration by numerous routes. BAP has produced positive results in numerous genotoxicity assays.
US EPA slope factor basis
Lists target organs used for estimating carcinogenic potency of the chemical (17).Oral: Forestomach, squamous cell papillomas and carcinomas; forestomach, larynx and esophagus, papillomas and carcinomas (combined)-mice sex unknown, male and female rat
NIOSH Pocket Guide - potential carcinogen?
This field indicates whether NIOSH identifies the chemical as a potential carcinogen for workers (yes/no) (24).NA
NIOSH Pocket Guide - cancer sites
Lists target organs from animal cancer bioassays (24).NA
Risk assessment summary
For 11 chemicals that are of particular interest because of recent regulatory attention, a Silent Spring Institute summary of how the evidence on mammary gland tumors and the potential for breast cancer was considered in major governmental risk assessments and regulations is available.Benzo[a]pyrene is the most well-studied of the PAHs, which are products of combustion processes. Primary sources of exposure to PAHs include tobacco smoke, grilled foods, and air pollution. Diesel exhaust and automobile exhaust are primary sources of PAH air pollution, and other contributors include coal, wood, and other fuel burning. Indoor concentrations of PAHs can also be elevated from cooking and burning of candles and incense. Cancer risk from diesel exhaust is a major contributor to overall cancer risk from air pollution -- for example the California Air Resources Board has estimated that 70% of cancer risk from toxic air pollution is due to diesel exhaust (focus is lung cancer). Most of the carcinogenic risk of diesel exhaust is estimated to come from PAHs, such as benzo[a]pyrene (1), and PAHs in diesel exhaust have been shown to cause mammary gland tumors in animals. Despite the fact that many PAHs have been consistently shown to cause mammary gland tumors, the US EPA IRIS (2) record on diesel exhaust does not mention mammary gland tumors or breast cancer and US EPA's 669-page Health Assessment Document for Diesel Exhaust (3) focuses exclusively on lung cancer, not discussing the potential for breast cancer. In contrast, risk assessments by IARC (4), the World Health Organization (1) and the NTP Report on Carcinogens (5) include discussion of mammary gland tumors. A search of PubMed for "diesel exhaust", risk assessment, and "breast cancer" did not produce any articles, and "diesel" with "breast cancer" brought up two in vitro studies.
Other governmental risk assessment documents
For 11 chemicals that are of particular interest because of recent regulatory attention, we identified and summarized risk assessment materials developed by a wide range of agencies and groups. We specifically searched for documents by the following organizations: California EPA Office of Health Hazard Assessment, Health Canada, IARC, International Program on Chemical Safety (IPCS), World Health Organization, RIVM (Dutch chemical standards agency), Toxicology Excellence for Risk Assessment ITER database and Peer Consultation documents, and by searching PubMed, ToxLine, the National Library of Medicine, and Google for documents related to “risk assessment” and the CAS No. or chemical name.Primary sources of exposure to PAHs include tobacco smoke, grilled foods, and air pollution. Diesel exhaust and automobile exhaust are primary sources of PAH air pollution, and other contributors include coal, wood, and other fuel burning. Indoor concentrations of PAHs can also be elevated from cooking and burning of candles and incense. Auto/diesel exhaust:Cancer risk from diesel exhaust is a major contributor to overall cancer risk from air pollution -- for example the California Air Resources Board has estimated that 70% of cancer risk from toxic air pollution is due to diesel exhaust (focus is lung cancer)(6). Most of the carcinogenic risk of diesel exhaust is estimated to come from PAHs, such as benzo[a]pyrene (4), and PAHs in diesel exhaust have been shown to cause mammary gland tumors in animals. However, neither the US EPA IRIS record on diesel exhaust(1) or US EPA's 669-page Health Assessment Document for Diesel Exhaust (2) mention mammary gland tumors or breast cancer. In contrast, risk assessments by IARC (4), the World Health Organization (1) and the NTP Report on Carcinogens (5) include discussion of mammary gland tumors. A search of PubMed for "diesel exhaust", risk assessment, and "breast cancer" did not produce any articles, and "diesel" with "breast cancer" brought up two in vitro studies.
Links to risk assessment summary
(1) - World Health Organization International Program on Chemical Safety. Environmental Health Criteria 229: Selected nitro- and nitro-oxy-polycyclic aromatic hydrocarbons. World Health Organization, Geneva, Switzerland, 2003. - Link
(2) - US EPA. Integrated Risk Information System Database for Risk Assessment. 2005. - Link
(3) - US Environmental Protection Agency. Health Assessment Document for Diesel Engine Exhaust. In: NCEA, ed.: NTIS, 2002. - Link
(4) - International Agency for Research on Cancer. Diesel and Gasoline Engine Exhausts. VOL. 46 (1989) (p. 41), 1989. - Link
(5) - National Toxicology Program: Department of Health and Human Services. 11th Report on Carcinogens. 2005. - Link