Environment and Breast Cancer: Science Review
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Major use
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.
Industrial chemical
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.
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)
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
Air pollutant
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).
Yes
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.
> 1 billion
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.
The general population may be exposed to ethylene oxide through use of products that have been sterilized with the compound, such as medical products, foods, clothing, cosmetics, beekeeping equipment, and other products. Ethylene oxide has been detected in tobacco smoke, automobile exhausts, and in some foods and spices (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.
5 consumer products listed with EPA contain chemical including: disinfectants (SRD). Home maintenance products, landscaping/yard products (HPD). Also used as chemical intermediate, for sterilizing medical equipment, for the fumigation of spices (IARC 1994 vol.:60 p.73). Used as an insecticide and to produce antifreeze and non ionic surfactants (found in soaps, detergents, and textile chemicals) (11th ROC). Currently registered for use as a pesticide in the US (PAN Pesticides Database).
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: 270,683 Females exposed: 120,086 Occupational fields: nurses, stock and inventory clerks, various machine operators, assemblers. Occupational exposure to ethylene oxide may occur among workers involved in ethylene oxide production, in the manufacture of its end products, or in the use of these compounds in hospital and industrial sterilization (11th ROC). Biomarkers of exposure/effect have been developed and applied in some studies - haemoglobin adducts indicate recent exposure to ethylene oxide; chromosomal damage to peripheral lymphcytes has been measured two years following cessation of exposure (IARC).
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).
NA
USA EPA notes
Any Silent Spring Institute notes on treatment of mammary tumors in US EPA
risk assessment.
EPA IRIS risk assessment in progress as part of FIFRA RED for ethylene oxide (1)
NIOSH Pocket Guide - potential carcinogen?
This field indicates whether NIOSH identifies the chemical as a potential
carcinogen for workers (yes/no) (24).
yes
OSHA-Is medical surveillance required?
This field indicates whether medical surveillance is
required for exposed workers and whether required surveillance includes breast exams or
mammography (25).
yes, but no mammography
NIOSH Pocket Guide - cancer sites
Lists target organs from animal cancer bioassays (24).
peritoneum, leukemia
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.
Listed as "known human carcinogen" in the 11th ROC, and mammary gland is mentioned as a target site in animal studies. An increased risk of breast cancer has been observed in some studies of exposed workers, but strongest evidence is for lymphatic and haematopoietic cancers. The US OSHA requires medical surveillance for workers exposed to ethylene oxide above the action level, but this regulation does not mention breast cancer or mammary gland tumors and the required surveillance does not include breast cancer screening (2). Regulatory agencies have determined that significant risks are associated with occupational exposure during sterilization of medical equipment and nuts/spices, and with ambient releases near point sources (3, 4).
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.
Health Canada (3) notes that "available epidemiological evidence for an association between exposure to ethylene oxide and lymphopoietic/hematopoietic cancer is suggestive," and that "while increases in mortality due to liver, colon, breast, bladder, kidney, esophageal, stomach, brain or pancreatic cancer have occasionally been reported in epidemiological studies of workers exposed to ethylene oxide, evidence is not consistent or convincing" Health Canada considered animal mammary tumors in its dose-response evaluation of ethylene oxide, but the incidence of monocellular leukemia in rats was the most sensitive cancer endpoint (3). IARC does not mention breast cancers in occupational studies, but does note mammary gland tumors in mice (5). Health Canada estimates that predicted cancer risks in the vicinity of industrial point sources, based on limited modelling and monitoring data, are greater than one per 100,000 (6). Occupational exposures, for example during sterilization of medical equipment and food/spices, are also expected to be associated with significant risk; for example "some of the cancer risks associated with the medical instrument sterilization use exceeded the US EPA's level of concern of 1 x 10-6 to 1 x 10-4 (i.e., risks range from 1.2 x 10-5 to 1.8 x 10-2). Some detail on these uses is provided in Health Canada 2001 and in US EPA FIFRA RED (draft) for ethylene oxide (3,7). The US EPA RED reviews breast cancer findings in the epidemiologic studies in some detail. The US OSHA requires medical surveillance for workers exposed to ethylene oxide above the action level, but this regulation does not mention breast cancer or mammary tumors and the required surveillance does not include breast cancer screening (2).
(1) - US EPA. IRIS Database for Risk Assessment. 2005. - Link
(2) - Occupational Safety and Health Administration. Medical surveillance guidelines for ethylene
oxide. vol. 29 CFR 1910.1047 App C. - Link
(3) - Health Canada. Canadian Environmental Protection Act, 1999: Priority Substances List Assessment Report for Ethylene Oxide. 2001. - Link
(4) - US Environmental Protection Agency. Preliminary Occupational Exposure Assessment of the Antimicrobial Uses of
Ethylene Oxide for the Reregistration Eligibility Decision (RED). 2005. - Link
(5) - International Agency for Research on Cancer. Ethylene Oxide. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, vol. 60, Some Industrial Chemicals. World Health Organization, 1994:73. - Link
(6) - Health Canada. Concise International Chemical Assessment Document (CICAD) for ethylene oxide. Concise International Chemical Assessment Document Vol:54, World Health Organization: 52 p.2003 - Link
(7) - US Environmental Protection Agency. Ethylene Oxide Risk Assessment; Notice of Availability. vol. 70: Federal Register, 2005:44632-34. - Link