Environment and Breast Cancer: Science Review
About
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.
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
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 - 10 million
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.
Detected in ambient air, soil, groundwater, and food. For general population, most important exposure through contaminated drinking water due to this chemical's former use as a gasoline additive. EPA estimated the daily intake from drinking water to range from 0 to 16 µg/kg per day. Ingestion of contaminated foods and inhalation of ambient air appear to be less important sources of exposure to 1,2-dibromoethane; EPA estimated the maximum intake from the former to be 0.09 µg/kg/day and from the latter to range from 0 to 79 µg/kg/day. However, inhalation of 1,2-dibromoethane released to indoor air from contaminated groundwater, such as while showering, may play an important role in human exposure (11th ROC). Exposure to ethylene dibromide (1,2-dibromoethane) may occur in pest control, petroleum refining and waterproofing (IARC 1999 vol.:71 p.641).
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. Used as a gasoline additive prior to 1990s, and consequently is an important groundwater contaminant. Was also used as a fumigant/pesticide (was used for post-harvest application to a variety of vegetable, fruit, and grain crops. It was also used to kill fruit flies on citrus fruits and in the soil to protect grasses in environments such as golf courses) (past uses); Currently, 1,2-dibromoethane is used as a chemical intermediate in synthesis and as a nonflammable solvent for resins, gums, and waxes. The major chemical made from 1,2-dibromoethane is vinyl bromide, which is used as a flame retardant in modacrylic fibers. It also has been used as an intermediate in the preparation of dyes and pharmaceuticals (11th ROC); not currently registered as a pesticide in the US (PAN Pesticides Database), but may be used outside the US.
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: 8,559 Females exposed: 792
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).
Weight of evidence narrative only
US EPA Weight of Evidence narrative
US EPA narrative statement of overall weight of
evidence for carcinogenicity (animal, human, and other supportive data).
Under the Draft Revised Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1999), 2-dibromoethane is considered "likely to be carcinogenic to humans" based on strong evidence of carcinogenicity in animals and inconclusive evidence of carcinogenicity in an exposed human population.
US EPA slope factor basis
Lists target organs used for estimating carcinogenic potency of the
chemical (17).
Oral: Forestomach tumors, hemangiosarcomas, thyroid follicular cell adenomas or carcinomas-male rat; Inhalation: Nasal cavity (includes adenoma, adenocarcinoma, papillary adenoma, squamous cell carcinoma, and or/papilloma), hemangiosarcomas, mesotheliomas-male rat
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).
no
Risk assessments not reviewed for this chemical