CAREX Canada

Full Profile

CAS No. 107-13-1

Photo: Wikimedia Commons^[1]

IARC Monograph Vol. 71, 1999 (Group 2B)

General Information

Acrylonitrile is a volatile, highly reactive, colourless liquid.^[2] It is soluble in water and many other common organic solvents.^[3] Acrylonitrile does not occur naturally,^[4] but has been an important industrial chemical since the 1940s.^[2]

Acrylonitrile may also be referred to as vinyl cyanide or cyanoethylene.^[5] There are numerous other synonyms and product names; see the HSDB for more information.^[5]

Acrylonitrile was classified by IARC in 1999 as Group 2B, possibly carcinogenic to humans, based on evidence in experimental animals.^[6] Acrylonitrile was found to be carcinogenic to rats with tumours reported in the central nervous system, mammary gland, and a few other rare tumour sites.^[6]

Several epidemiological studies in the 1970s and 80s noted a link between occupational acrylonitrile exposure and lung cancer, however these findings have not been conclusively confirmed in more recent, larger studies.^[6]

Inhalation of acrylonitrile can cause respiratory irritation and, at higher levels, neurological symptoms including dizziness, weakness, headache, and impaired judgment.^[7] Dermal exposure can result in skin irritation and blistering.^[7]

Acrylonitrile has been ranked by CAREX Canada as Group A (immediate high priority) for occupational settings and as Group B (possible high priority) for environmental settings. 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	2 [sk]
BC, AB, MB, ON, NL, PE, NB, NS	2 [sk]
SK	2 [sk] 4 [stel]
QC	2 [sk, em]
YT	20 [sk]
NT, NU	2 [sk] 4 [stel]
Other Jurisdiction	OEL (ppm)
ACGIH 2011 TLV	2 [sk]

ppm = parts per million

sk = easily absorbed through the skin

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

em = exposure must be reduced to the minimum

Canadian Environmental Guidelines

Acrylonitrile was not included in the Canadian government environmental guidelines reviewed.^[8,9]

Canadian Agencies/Organizations

Agency	Designation/Position	Year
Health Canada	DSL – low priority substance (already risk managed)	2006^[10]
CEPA	Schedule 1, paragraph 'c' (human health)	1999^[11]
Environment Canada	Pollution Prevention Plans – Part 4 of CEPA 1999	2003^[3]

Main Uses

Acrylonitrile has widespread use in a variety of industrial applications.^[2] It is used extensively, for example, in the manufacture of acrylic fibres, resins, plastics, and nitrile rubbers.^[2] Common resins containing acrylonitrile includes acrylonitrile-butadiene-styrene (ABS), used in business machines and construction material, and styrene-acrylonitrile (SAN), used in automotive applications, household goods and packaging.^[2]

A significant use of acrylonitrile is as a chemical intermediate in the production of adiponitrile (used in nylon production) and acrylamide.^[6] Speciality applications of acrylonitrile include the production of carbon fibres used to reinforce composites for applications such as aircraft and the aerospace industry.^[6]

Historically, acrylonitrile was used as a pesticide when mixed with carbon tetrachloride;^[3] the use of acrylonitrile as a pesticide ceased in Canada in 1976.^[4]

Canadian Production and Trade

Acrylonitrile is not produced in Canada, but it is imported for the production of adiponitrile, nitrile-butadiene rubber, diamines, ABS polymers, SAN polymers, and styrene-butadiene latex.^[12,13] As of 1999, nitrile-butadiene rubber (NBR – a copolymer of acrylonitrile and butadiene) was produced by one Canadian company with a forecasted production of 30,000 tonnes for 2001.^[14]

With no domestic producers, Canadian companies are reliant on imports of acrylonitrile.^[13] The US, the largest global manufacturer of acrylonitrile, produces approximately 1.5 million tonnes per year.^[4] The EU and Asia are also major producers.^[4] As of 2004, the major buyers of acrylonitrile in Canada included Akzo Chemicals, Saskatoon, SK; Bayer Rubber, Sarnia, ON; Dow Chemical, Varennes, QC; and Solutia Canada, LaSalle, QC.^[13]

Production and Trade

Activity	Quantity	Year
Domestic Consumption	2,000 t	2005^[13]
Export: None	None	2010^[15]
Import: Mainly from US	2,598 t of 'acrylonitrile'	2010^[15]

t=tonne

Occupational Exposures

Inhalation and dermal contact are the most important routes of occupational exposure.^[4] Highest exposures are expected when acrylonitrile is used to make other products, where it may not be as easily contained.^[4] European occupational exposure data was summarized in a risk assessment by the EU; the highest mean exposures were found in fibre production, although they were still ≤ 1 ppm.^[16]

Occupations commonly exposed include those involved in the production of acrylonitrile,^[2] and in the manufacture of synthetic rubber, acrylic resins, acrylamide and synthetic fibres.^[4]

Further exposures can occur during industrial processes such as burning of synthetic polymers, working with glues and adhesives, and firefighting.^[17] Firefighters may be exposed to acrylonitrile because the chemical can be released from burning plastics.^[17] Yet acrylonitrile is very flammable itself and is likely to burn off in a fire, producing hydrogen cyanide, another very toxic gas.^[18]

Environmental Exposures

According to Health Canada, the main route of exposure to acrylonitrile for the general population is indoor air, followed by ambient air.^[12] Exposure is expected to be higher near industrial point sources.^[3]

Children may be exposed to higher levels than adults, due to their lung surface:body weight ratio, and because concentrations may be higher closer to the ground (acrylonitrile is heavier than air).^[3]

In Canada, the two major sources of acrylonitrile released into the environment are the organic chemical industry (97.4%) and municipal wastewater treatment facilities (2.6%).^[3,12] During the 1990s, most acrylonitrile releases reported to the NPRI were from synthetic rubber manufacturers, although this sector voluntarily decreased their emissions by 66% between 1994 and 1999, primarily due to control of fugitive emissions by one company.^[3]

In 2003, under CEPA 1999, notice was published in the Canadian Gazette requiring the synthetic rubber industry to prepare and implement Pollution Prevention Plans to reduce acrylonitrile emissions to the lowest achievable levels.^[19] Emissions from plastic manufacture, however, have risen substantially since 2000, such that total emissions in 2006 were over four times the emissions in 2000.^[20]

Tobacco smoke contributes to indoor air levels of acrylonitrile. In 1990, the ATSDR speculated that cigarette smoking would no longer be a major source of exposure since acrylonitrile use as a fumigant on stored tobacco crops had been discontinued.^[3] Recent studies, however, report that acrylonitrile is emitted directly from cigarettes,^[21] and that tobacco smoke is a significant source of acrylonitrile in indoor air.^[21]

In the past, vehicle exhaust was a source of acrylonitrile. With the improved catalysts in engines today, little if any acrylonitrile is expected to enter the environment in this way.^[12]

There is limited data to assess the exposure to acrylonitrile through foodstuffs.^[12] Although a past Canadian study suggested the potential for acrylonitrile to migrate into foodstuffs from acrylonitrile-based polymers used in food packaging,^[26] Health Canada reports that the packaging is currently not extensively used in Canada where food is in direct contact.^[12]

The sale of food containing acrylonitrile is prohibited under the Food and Drug Act.^[12] Acrylonitrile has not been detected above trace amounts in Canadian ambient surface water or drinking water.^[4]

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

NPRI and US Household Products Database

NPRI 2009^[20]
Search term: 'acrylonitrile'
Category	Quantity	Industry
Released into Environment	4.9 t	Plastics and foams products, resin and rubber manufacture (7 companies)
Disposed of	4.8 t
Sent to off-site recycling	None

US Household Products 2010^[22]
Search Term	Quantity	Product Type
'acrylonitrile polymer'	1	Auto defogger (1)
'acrylonitrile copolymer'	6	Olay® body washes (6)
'ABS copolymer'	2	adhesives (2)