CAREX Canada

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CAS No. 100-41-4

Photo: Wikimedia Commons^[1]

IARC Monograph Vol. 77, 2000 (Group 2B)

General Information

Ethylbenzene is a volatile organic compound (VOC) in the ‘BTEX’ substance group which includes benzene, toluene, ethylbenzene and xylene.^[2] Ethylbenzene is a colourless liquid that smells similar to gasoline.^[2] It exists naturally in petroleum, and is also an industrial chemical with a variety of uses.^[3]

Ethylbenzene may be referred to as phenylethane or EB.^[3] See the HSDB for other synonyms and more information.^[3]

Ethylbenzene has been classified by IARC as Group 2B, possibly carcinogenic to humans.^[4] Available epidemiological studies do not provide adequate evidence of carcinogenicity in humans, however animal studies show an increase in lung and liver cancers in mice and kidney cancers in rats exposed to ethylbenzene.^[4]

Additionally, short term exposure to high concentrations of ethylbenzene can cause eye and throat irritation. Chronic exposure may also cause haematological effects and damage to the inner ear.^[5]

Ethylbenzene has been ranked by CAREX Canada for both the occupational and environmental settings as Group A (immediate high priority). Prioritization was based on the carcinogenicity and other toxic properties of the substance, the prevalence of exposure in Canada, and the feasibility of assessing exposure.

Regulations and Guidelines

Occupational Exposure Limits (OEL)

Canadian Jurisdictions	OEL (ppm)
Canada Labour Code	20
BC, MB, NL, PE, NB, NS	20
AB, SK, QC, YT, NT, NU	100 125 [stel]
Other Jurisdiction	OEL (ppm)
ACGIH 2011 TLV	20

ppm = parts per million

stel = short term exposure limit (15 min. maximum)

Canadian Environmental Guidelines

Jurisdiction	Limit	Year
Canadian Drinking Water Guidlines	< 0.0024 mg/L	2005^[6]

Ethylbenzene was not included in other Canadian government environmental guidelines reviewed.^[7,13,14]

Canadian Agencies/Organizations

Agency	Designation/Position	Year
Health Canada*	DSL – high priority substance with greatest potential for exposure	2006^[8]

*Under CEPA 1999, ethylbenzene was chosen for screening to investigate potential for the substance to enter the environment in harmful amounts. A State of the Science Report was commissioned to provide a profile of current use and exposure across Canada, including information up until May 2005.^[10] The compound was still undergoing a risk assessment as of August 2011.^[11]

Ethylbenzene was not included in other Canadian government chemical listings reviewed.^[9,15]

Main Uses

Pure ethylbenzene is used almost exclusively as a precursor for styrene production.^[4]

Ethylbenzene is often found in mixed xylene solvents (at up to 25%) which are used in paints, coatings, lacquers, varnishes, adhesives, inks, insecticides, cleaning materials, dyes, perfumes, pharmaceuticals, rubber and plastics.^[4,5,12] It is also used as a solvent and in the production of various other chemicals, and is also found in asphalt and naphtha, tobacco products,^[4] and gasoline (at up to 15%).^[4]

Canadian Production and Trade

Almost all ethylbenzene in Canada is produced by the alkylation of benzene for the industrial production of styrene, although small amounts may be marketed for solvent use.^[16] Thus, ethylbenzene demand follows the same market fluctuations as styrene, and was generally strong from 2002-2006.^[16]

As of 2006, there were 2 Canadian companies producing ethylbenzene (in Sarnia, Ontario and Scotford, Alberta).^[16]

Production and Trade

Activity	Quantity	Year
Canadian Production	930,000 t	2006 (forecasted in 2004)^[16]
Domestic Consumption	930,000 t	2006 (forecasted in 2004)^[16]
Export: Mainly to US	421 t of ‘ethylbenzene’	2010^[17]
Import: Mainly from US	138 t of ‘ethylbenzene’	2010^[17]

t = tonne

Occupational Exposures

Inhalation is the most important route of occupational exposure.^[5]

Occupational exposure to ethylbenzene can occur during the production and handling of ethylbenzene.^[4] More commonly, occupational ethylbenzene exposures occur during the use of mixed xylenes, which are used as solvents for paints, inks, lacquers, etc., and in rubber and plastic production.^[4] Exposures are also common in coal and petroleum refining and in the production and handling of gasoline and bitumens.^[5]

Transportation workers (i.e. service station attendants, drivers) can be exposed to ethylbenzene, particularly near gas pumps and areas where combustion products accumulate, such as tunnels, highways and parking lots.^[5]

Styrene production is typically accomplished using a closed process which limits the potential for exposure.^[18] Low levels of ethylbenzene, however, were reported in the 1990s as a by-product of styrene production.^[5]

Environmental Exposures

According to Health Canada, the primary source of ethylbenzene exposure is indoor air.^[10] Ethylbenzene has also been detected in outdoor air, drinking water, soil and food.^[10]

Sources of atmospheric ethylbenzene include petroleum and coal refining, evaporation from solvents and thinners, and vehicle emissions.^[12] Tobacco and wood smoke also contain ethylbenzene.^[20]

Sources of soil and groundwater contamination include leaking underground gasoline storage tanks, landfill sites, transportation spills, pesticide use, municipal waste, and industrial discharges.^[20] Ethylbenzene is allowed for use as a formulant in pesticide preparations in Canada, but not an active ingredient.^[19]

Exposure estimates to ethylbenzene in consumer products were produced for Health Canada’s State of the Science Report. Exposure sources included acrylic enamel aerosol spray paint, latex wall paint, gasoline and cigarettes.^[10] In Ontario, ethylbenzene is typically 1.4% of regular unleaded gasoline and 1.7% of premium unleaded gasoline.^[12]

Estimates of daily intake for the general population were also calculated using values for indoor and outdoor air, drinking water, food and beverages and soil. Estimates ranged from 95 to 287 µg/kg-body weight per day depending on age.^[10]

In the environment, ethylbenzene typically exists as a vapour. It can also bind to some soils and clay minerals, but tends to be mobile enough to be of concern for groundwater contamination.^[5]

Searches of environmental and consumer product databases yielded the following results on current potential for exposure to ethylbenzene in Canada:

NPRI and US Household Products Database

NPRI 2009^[21]
Search term: ‘ethylbenzene'
Category	Quantity	Industry
Released into Environment	878 t	Oil sands, refineries, and vehicle manufacture (292 companies)
Disposed of	1.1 t
Sent to off-site recycling	None