Ethylbenzene Profile
INDUSTRIAL CHEMICALS – POSSIBLE CARCINOGEN (IARC 2B)
Contents
Ethylbenzene Profile
General Information
Ethylbenzene is a volatile organic compound (VOC) in the ‘BTEX’ substance group which includes benzene, toluene, ethylbenzene, and xylene.[1] Ethylbenzene is a colourless liquid that smells similar to gasoline.[1] It exists naturally in petroleum, and is also an industrial chemical with a variety of uses.[2] Ethylbenzene may be referred to as phenylethane or EB.[2] See the Hazardous Substances Data Bank (HSDB) for other synonyms and more information.[2]
Ethylbenzene has been classified by the International Agency for Research on Cancer (IARC) as Group 2B, possibly carcinogenic to humans.[3] Available epidemiological studies did not provide adequate evidence of carcinogenicity in humans, however animal studies showed an increase in lung and liver cancers in mice and kidney cancers in rats exposed to ethylbenzene.[3]
Additionally, short term exposure to high concentrations of ethylbenzene can irritate eyes and throat. Chronic exposure may also cause haematological effects and damage to the inner ear.[4]
Regulations and Guidelines
Occupational exposure limits (OEL) [5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]
| Canadian Jurisdictions | OEL (ppm) |
|---|---|
| Canada Labour Code | 20 |
| AB, NB, NT, NU, QC, SK, YT | 100 125 [stel] |
| BC, MB,NL, NS, ON, PE | 20 |
| Other Jurisdiction | OEL (ppm) |
| ACGIH 2020 TLV | 20 |
ppm = parts per million
stel = short term exposure limit (15 min. maximum)
ACGIH = American Conference of Governmental Industrial Hygienists
TLV = threshold limit value
Canadian environmental guidelines and standards*
| Jurisdiction | Limit | Year |
|---|---|---|
| Drinking Water Guidelines (Canada, BC) and Standards (ON) | 0.14 mg/L | 2014-2020 [20,21,22] |
| Ontario Ambient Air Quality Criteria | 24 hour: 1000 µg/m3 | 2016[23] |
| **10 minute: 1900 µg/m3 | 2012[23] | |
| Alberta Ambient Air Quality Objectives and Guidelines | 1 hr: 2000 μg/m3 | 2005[24] |
| Government of Canada’s Indoor Air Reference Levels | 2000 µg/m3 (critical effect: kidney, pituitary gland, and liver effects) | 2018[25] |
| Ontario’s Air Pollution – Local Air Quality Regulation | 24-hour standard: 1000 µg/m3; Prohibited discharge into the air if the concentration of ethylbenzene exceeds the standard | 2020[26] |
| Quebec’s Clean Air Regulation | 4 minute limit: 740 µg/m3 1 year limit: 200 µg/m3; Prohibited discharge into the air if the concentration of ethylbenzene exceeds the standard |
2011[27] |
| BC’s Contaminated Sites Regulation, BC Reg 375/96 | Sets soil standards for: Agricultural and low density residential soil: 4000 μg/g Urban park and high density residential soil: 8500 μg/g Commercial soil: 25 000 μg/g Industrial soil: 700 000 μg/gDrinking water standards: 140 μg/L
Sets vapour standards for the protection of human health: |
2017[28] |
mg/L = milligrams per litre
µg/m3 = micrograms per cubic meter
µg/g = micrograms per gram
µg/L = micrograms per litre
* Standards are legislated and legally enforceable, while guidelines (including Ontario ambient air quality criteria) describe concentrations of contaminants in the environment (e.g. air, water) that are protective against adverse health, environmental, or aesthetic (e.g. odour) effects
** for limiting the effect of odour
Canadian agencies/organizations
| Agency | Designation/Position | Year |
|---|---|---|
| Health Canada* | DSL – high priority substance with greatest potential for exposure | 2006[29] |
| National Classification System for Contaminated Sites | Rank = “Medium hazard” | 2008[30] |
| PMRA list of formulants | List 2 contains formulants that are considered to be potentially toxic, based on either structural similarity to List 1 formulants or data suggestive of toxicity, and are of high priority for testing. | 2020[31] |
| Environment Canada’s National Pollutant Release Inventory | Reportable to NPRI if manufactured, processed, or otherwise used at quantities greater than: 10 tonnes. | 2016[32] |
* Under the Canadian Environmental Protection Act (CEPA) 1999, ethylbenzene was chosen for screening to investigate its potential to enter the environment in harmful amounts. This screening assessment includes updated information: ecological sections include recent literature searches up to December 2009 and the human health sections include information up to January 2013.[33] The final screening assessment, published in April 2016, concluded that ethylbenzene does not constitute a danger to human health or life.[34]
DSL = domestic substance list
Ethylbenzene was not included in other Canadian government guidelines, standards, or chemical listings reviewed.
Main Uses
Pure ethylbenzene is used almost exclusively as a precursor for styrene production.[3]
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.[3,4,35] It is also used as a solvent and reagent for making various other chemicals. It is found in asphalt and naphtha, tobacco products,[3] and gasoline (at up to 15%).[3]
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.[36]
Production and trade
| Activity | Quantity | Year |
|---|---|---|
| Export | 1 t of ‘ethylbenzene’ | 2021[37] |
| Import | 365 t of ‘ethylbenzene’ | 2021[37] |
t = tonne
Environmental Exposures Overview
According to Health Canada, the primary route of ethylbenzene exposure is inhalation.[33] CAREX Canada estimates that ethylbenzene levels in indoor air result in an increased risk of cancer (high data quality).
Ethylbenzene has also been detected in outdoor air, drinking water, soil, and food.[33] CAREX Canada estimates that ethylbenzene levels in outdoor air (high data quality), drinking water (moderate data quality), and food and beverages (very low data quality) do not result in increased risks of cancer.
Sources of atmospheric ethylbenzene include petroleum and coal refining, evaporation from solvents and thinners, and vehicle emissions.[35] Tobacco and wood smoke also contain ethylbenzene.[35]
In the environment, ethylbenzene typically exists as a vapour. It can also bind to some soils and clay minerals, but is mobile enough to cause concern as a potential groundwater contaminant.[4] Sources of soil and groundwater contamination include leaking underground gasoline storage tanks, landfill sites, transportation spills, municipal waste, industrial discharges, and pesticide use.[34,35] Ethylbenzene is allowed to be used as a formulant in pesticide preparations in Canada.[34,38]
Ethylbenzene has been detected in numerous consumer products including acrylic enamel aerosol spray paint, latex wall paint, gasoline, and cigarettes.[33] In Ontario, ethylbenzene is typically 1.4% of regular unleaded gasoline and 1.7% of premium unleaded gasoline.[33]
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 9.83 to 28.7 µg/kg-body weight per day depending on age.[33]
Searches of Environment Canada’s National Pollutant Release Inventory (NPRI) and the US Consumer Product Information Database yielded the following results on current potential for exposure to ethylbenzene in Canada:
NPRI and US Consumer Product Information Database
| NPRI 2015[39] | ||
|---|---|---|
| Substance name: ‘Ethylbenzene’ | ||
| Category | Quantity | Industry |
| Released into Environment | 378 t | Oil sands, vehicle manufacture, petroleum and coal product manufacturing, metal manufacturing (224 facilities) |
| Disposed of | 223 t | |
| Sent to off-site recycling | 1,956 t | |
t = tonne
| US Consumer Products 2016[40] | ||
|---|---|---|
| Search Term | Quantity | Product Type |
| ‘Ethylbenzene’ | >449 | Hobby paints, home interior and exterior paints, decorative snow materials, and five insecticides |
For more information, see the environmental exposure estimate for ethylbenzene.
Occupational Exposures Overview
Inhalation is the most important route of occupational exposure.[4]
CAREX Canada estimates that approximately 217,000 Canadians are exposed to ethylbenzene in their workplaces. Industrial groups that typically operate in or around areas where combustion products accumulate tend to be at higher risk for ethylbenzene exposure. The largest exposed industrial groups are automotive repair and maintenance, public administration (includes firefighters), taxi and limousine services, and automotive dealers. The largest exposed occupational groups are automotive service technicians, truck and bus mechanics, firefighters, and professional drivers (e.g. taxi, limousine, or truck drivers, chauffeurs).
Occupational exposure to ethylbenzene can also occur during production and handling of ethylbenzene or while using mixed xylenes, which are used as solvents for paints, inks, lacquers, and in rubber and plastic production.[3] Exposure can also occur in coal and petroleum refining and in production and handling of gasoline and bitumens.[4]
Although ethylbenzene is used in styrene production, exposure is expected to be low since the process is typically enclosed.[41] Low levels of ethylbenzene were reported in the 1990s as a by-product of styrene production.[4]
For more information, see the occupational exposure estimate for ethylbenzene.
Sources
Other Resources
- BC Ministry of the Environment. Environment Protection Division: Ambient air quality guidelines for Ethylbenzene; overview report (1981)
- World Health Organization (WHO). Ethylbenzene in Drinking Water (1996) (PDF)
- Agency for Toxic Substances and Disease Registry (ATSDR). ToxGuide for Ethylbenzene (2007) (PDF)
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