Environment and Breast Cancer: Science Review

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CAS RN 100-42-5

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
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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.
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)
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).
Not 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.
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).
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.
Production and use in plastic and resin manufacture may result in its release to the environment through various waste streams. It has been found in exhausts from combustion engines, waste incineration, and cigarette smoke. The general population may be exposed to styrene via ingestion of drinking water and by inhalation of air contaminated by industrial sources, auto exhaust, or incineration emission, and by inhalation of smoke from cigarettes. Typical concentrations of styrene in air and drinking water in US are 0.6 ug/cu m and 0 to 18.4 ug/l, respectively. Exposure may also occur through the use of consumer products containing styrene; styrene and styrene oligomers leach from polystyrene food-contact articles - estimated 9 micrograms/day styrene, on average, in the daily diet of people in the US (Lickly 1995). Exposure to the general population occurs at levels of micrograms per day due mainly to inhalation of ambient air and cigarette smoke and intake of food that has been in contact with styrene-containing polymers (IARC 2002 vol.:82 p.437).
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.
24 consumer products listed with EPA contain styrene including: carpets and rugs, adhesives, building materials (insulation, flooring), hobby and craft supplies, home matainence products (filler putty) (SRD) (HPD). Styrene's major use is in the production of polystyrene (plastic packaging, disposable cups and containers), insulation, acrylonitrile-butadiene-styrene resins, styrene-butadiene rubbers and latexes, and unsaturated polystyrene resins (IARC 1994 vol.:60 p.233). A widely used intermediate in the manufacture of plastics, elastomers, and resins (NTP Report No. 185).
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: 333,212 Females exposed: 86,902 Occupational fields exposed: janitors and cleaners, assemblers, various machine operators, maids and housemen, health aids (except nurses), food preparation occupations
US EPA cancer classification
The US EPA Weight of Evidence Characterization of the chemicalís 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).
USA EPA notes
Any Silent Spring Institute notes on treatment of mammary tumors in US EPA risk assessment.
No carcinogenicity assessment
NIOSH Pocket Guide - potential carcinogen?
This field indicates whether NIOSH identifies the chemical as a potential carcinogen for workers (yes/no) (24).
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).
NIOSH Pocket Guide - cancer sites
Lists target organs from animal cancer bioassays (24).
not listed as potential carcinogen
Risk assessments not reviewed for this chemical