INDUSTRIAL CHEMICALS – KNOWN CARCINOGEN (IARC 1)
- A by-product of incomplete combustion of organic matter; produced commercially for industrial use
- Associated cancers: Blood and lymphatic system cancers
- Most important route of exposure: Inhalation
- Uses: Found in synthetic elastomers (ex. in automobile tires), butadiene rubbers (ex. in rubber products, chewing gum), and styrene-butadiene latex (ex. in coated paper, flooring)
- Occupational exposures: Approx. 3,300 Canadians are exposed at work, primarily in basic chemical manufacturing and oil and gas extraction industries
- Environmental exposures: Via combustion sources in indoor and outdoor air such as vehicle exhaust, cigarette smoke, cooking, heating, and forest fires
- Fast fact: Newer vehicles with catalytic converters emit less 1,3-butadiene than older vehicles.
1,3-Butadiene is a non-corrosive colourless gas with an odour similar to that of gasoline. It is emitted as a byproduct of incomplete combustion of organic matter, and is produced commercially for use in the chemical polymer industry. 1,3-Butadiene may also be referred to as butadiene or vinylethylene. There are numerous other synonyms and product names; see the Hazardous Substances Data Bank (HSDB) for more information.
1,3-Butadiene has been classified by the International Agency for Research on Cancer (IARC) as Group 1, carcinogenic to humans, with sufficient evidence of carcinogenicity in humans. 1,3-Butadiene causes cancer of the haematolymphatic organs, and this is also supported by sufficient evidence of carcinogenicity in animals.
Concurrent exposure to other chemicals complicates analysis of additional adverse health effects related to 1,3-butadiene. However, cardiovascular and respiratory effects have been reported. Low levels of exposure may result in sensory irritation while short term high levels may damage the central nervous system. Dermal exposure to liquid 1,3-butadiene can cause irritation and frostbite. Animal data indicates potential for reproductive effects, although there is as yet no evidence in humans.
Regulations and Guidelines
|Canadian Jurisdictions||OEL (ppm)|
|Canada Labour Code||2|
|BC, AB, MB, NB, NS, NL, ON, PE, QC||2|
|NT, NU, SK||2
|Other Jurisdiction||OEL (ppm)|
|ACGIH 2020 TLV||2|
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*
|Cosmetics Hotlist||Not Permitted||2011|
|National Classification System for Contaminated Sites||Rank= “High hazard”, confirmed human carcinogen||2008|
|BC’s Contaminated Sites Regulation, BC Reg 375/96||Sets soil standards for the protection of human health:
Agricultural and low density residential sites: 2 μg/g
Urban park and high density residential sites: 4 μg/g
Commercial and industrial sites: 9.5 μg/g
Drinking water: 1 μg/L
Sets vapour standards for the protection of human health:
|Ontario Ambient Air Quality Criteria||Annual: 2 µg/m3
24-hour: 10 µg/m3
|Ontario’s Air Pollution – Local Air Quality Regulation Standards||Annual: 2 µg/m3; Prohibited discharge into the air if the concentration of 1,3-butadiene exceeds the annual standard||2020|
|Government of Canada’s Indoor Air Reference Levels||1.7 µg/m3 (critical effect: leuekmia)||2018|
*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
|Health Canada||DSL – low priority substance (already risk managed)||2006|
|CEPA||Schedule 1, paragraphs ‘b’ and ‘c’||1999|
|Challenge to Industry||Batch 2||2009|
|Environment Canada’s National Pollutant Release Inventory||Reportable to NPRI if manufactured, processed, or otherwise used at quantities greater than 10 tonnes or if released at quantities greater than 1 tonne of 10-tonne total VOC air release||2016|
DSL = domestic substance list
CEPA = Canadian Environmental Protection Act
1,3-Butadiene was not included in other Canadian government guidelines, standards, or chemical listings reviewed.
1,3-Butadiene is used primarily to manufacture synthetic elastomers, including polybutadiene rubber used in automobile tires, vehicle parts, and appliance and electrical equipment components; styrene-butadiene rubber used in rubber products and chewing gum; styrene-butadiene latex, used in coated paper, certain types of flooring, adhesives, and tire cord latex; and nitrile-butadiene rubber, a copolymer of butadiene and acrylonitrile used in products that require oil resistance, such as hoses and belting.
Other uses include neoprene rubber, ABS resins, co-polymer resins and latexes for paints, coatings and adhesives, oil lubricant additives, and rocket propellants. A non-polymer use is for producing adiponitrile, a nylon intermediate.
1,3-Butadiene has also been used to produce the agricultural fungicides captan and captafol.
Environmental Exposures Overview
The most important route of exposure for the general Canadian population is inhalation.
CAREX Canada’s environmental estimates indicate that 1,3-butadiene levels in indoor air result in an increased lifetime risk of cancer at a population level (moderate data quality). Factors contributing to indoor levels of butadiene include cigarette smoke, proximity to a vehicle exhaust source (traffic or garage), cooking activity involving heated fats and oils (such as Chinese grapeseed, peanut, soybean and canola oils), wood burning, and natural gas/oil space heating.
CAREX Canada estimates that levels of 1,3-butadiene in outdoor air may also result in an increased risk of cancer (high data quality). Factors contributing to levels in outdoor air include forest fires, vehicle emissions, aircraft, marine and rail transportation, waste incinerator emissions, and thermal breakdown of butadiene-based rubbers and plastics.[1,2] Newer vehicles with catalytic converters emit less 1,3-butadiene than older vehicles.
Butadiene is not persistent in air and has an atmospheric half life of a few hours, depending on weather conditions. Levels in ambient air have been measured at several sites across Canada since 1987. Data published in 2006 indicates that the average 1,3-butadiene concentration from 2000-2003 was 0.22µg/m3 and 0.02 µg/m3 for urban and rural sites, respectively. The highest recorded 24-hour concentration was 2.58 µg/m3, measured near an industrial point source in Sarnia in 2001. Other industrial point sources where concentrations may be high include Yellowknife, Fort McMurray, Port Mellon, Montreal/Varennes, and Oakville. However, industrial emissions have declined since 2004.
There is currently little available data to indicate whether butadiene is present in drinking water, food, and soil in Canada. The potential for butadiene to migrate to food from containers exists, but is expected to be minimal; this route of exposure is likely much less important than inhalation.
Searches of environmental and consumer product databases yielded the following results on current potential for exposure to 1,3-butadiene in Canada:
NPRI and US Consumer Product Information Database
|Substance name: ‘1,3-Butadiene’|
|Released into Environment||26 t||Manufacturing (basic chemical; resin, synthetic
rubber, and fibres; petroleum and coal product),
oil and gas extraction,
pulp, paper and paperboard mills (21 facilities)
|Disposed of||0.049 t|
|Sent to off-site recycling||0.004 t|
|US Consumer Products 2016|
|Search Term||Quantity||Product Type|
|‘butadiene’||4||Roofing and cement adhesives|
t = tonne
For more information, see the environmental exposure estimate for 1,3-butadiene.
Inhalation is the most important route of occupational exposure. The potential for exposure exists in petroleum refining, as well as during production of purified butadiene monomer, various butadiene-based rubber and plastic polymers, and rubber and plastic products, such as tyres, hoses and a variety of molded objects.
CAREX Canada estimates that approximately 3,300 Canadians are exposed to 1,3-butadiene in their workplaces. The largest industrial groups exposed are basic chemical manufacturing, oil and gas extraction, and petroleum and coal product manufacturing. The largest exposure groups by occupation are construction trades helpers and labourers, central control and process operators in petroleum, gas and chemical processing, and rubber processing machine operators and related workers.
For more information, see the occupational exposure estimate for 1,3-butadiene.
- US Environmental Protection Agency (EPA). Integrated Risk Information System (IRIS) Chemical Assessment Summary (2002) (PDF)
- Cheng H, et al. “1,3-Butadiene and leukemia among synthetic rubber industry workers: Exposure response relationships.”Chemico-Biological Interactions 2007;166(1-3):15-24.
- Sathiakumar N, Graff J, Macaluso M, Maldonado G, Matthews R, Delzell E. “An updated study of mortality among North American synthetic rubber industry workers.” Occup and Environ Med 2005;62:822-829.
- Hughes K, Meek ME, Walker M, Beauchamp R. “1,3-Butadiene: Exposure Estimation, Hazard Characterization, and Exposure- Response Analysis.” J of Toxicol Environ Health B: Crit Rev 2003;6(1):55-83.
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