Acetaldehyde Profile

INDUSTRIAL CHEMICALS  POSSIBLE CARCINOGEN (IARC 2B)

CAS No. 75-07-0
IARC Monograph Vol. 71, 1999 (Group 2B)

Acetaldehyde Profile

General Information

Acetaldehyde is a colourless and volatile liquid with a sharp and fruity odour.[1] It is widely used industrially as a chemical intermediate.[2] Acetaldehyde is also a metabolite of sugars and ethanol in humans,[2] is found naturally in the environment, and is a product of biomass combustion.[3] It may also be referred to as ethanal or acetic aldehyde. There are numerous other synonyms and product names; see the Hazardous Substances Data Bank (HSDB) for more information.[4]

Acetaldehyde has been classified by the International Agency for Research on Cancer (IARC) as Group 2B, possibly carcinogenic to humans, based on evidence in animals.[2] Acetaldehyde is a respiratory tract carcinogen in experimental animals, especially of the nasal mucosa in rats and of the larynx in hamsters.[2]

There is inadequate evidence for the carcinogenicity of acetaldehyde in humans. One small study of workers manufacturing several types of aldehydes found increased risk of bronchial tumours, but workers were exposed to many other chemicals in addition to acetaldehyde.[2] Three other studies on the carcinogenicity of alcoholic beverages found that people who developed cancer after heavy alcohol use had genetic differences and higher concentrations of acetaldehyde in their blood compared to those who didn’t develop cancer.[2] Further study is required to establish a causal relationship.

Acetaldehyde can cause respiratory and eye irritation and in severe cases, lung edema.[4] It also exacerbates the effects of alcohol and is a central nervous system depressant.[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 25 [c]
BC, AB, SK, MB, NU, ON, QC, NL, PE, NS, NT 25 [c]
NB, YT 100
150 [stel]
Other Jurisdiction OEL (ppm)
ACGIH 2018 TLV 25 [c]
ppm = parts per million
c = ceiling (not to be exceeded at any time)
stel = short term exposure limit (15 min. maximum)
ACGIH = American Conference of Governmental Industrial Hygienists
TLV = threshold limit value

Canadian Environmental Guidelines

Jurisdiction Limit Year
Residential Indoor Air Quality 5 ppm 1987[20]
Ontario Ambient Air Quality Criteria 24 hour: 500 μg/m3
1/2 hour: 500 μg/m3
2016[21]
Alberta Ambient Air Quality Criteria 1 hour: 90 μg/m3 2017[22]
ppm = parts per million

Acetaldehyde was not included in other Canadian government environmental guidelines reviewed.[23,24,25,26,27,28]

Canadian Agencies/Organizations

Agency Designation/Position Year
Health Canada DSL – low priority substance (already risk managed) 2006[29]
CEPA Schedule 1, paragraphs ‘b’ and ‘c’ 1999[30]
Agreement Respecting the Great Lakes Basin Ecosystem Listed as a “Hazardous Polluting Substance” 1987[31]
National Classification System for Contaminated Sites Rank = “High hazard”, potential human carcinogen 2008[32]
Environment Canada’s National Pollutant Release Inventory Reportable to NPRI if manufactured, processed, or otherwise used at quantities greater than 10 tonnes 2016[33]
PMRA List of Formulants List 3: formulants that do not meet the criteria of any of the other lists 2017[34]
DSL = domestic substance list
CEPA = Canadian Environmental Protection Act

Acetaldehyde was not included in other Canadian government chemical listings reviewed.[35]

Main Uses

Acetaldehyde is used primarily as a chemical intermediate, especially in producing acetic acid, pyridine, and butylene glycol.[1]

Acetaldehyde is also used as a food additive for flavouring.[1] In the US, it falls under the Food and Drug Administration’s definition of “generally recognized as safe” (GRAS),[36] although some researchers have been calling for a re-evaluation of this classification.[37] Acetaldehyde is also used to produce some fragrances and flavours, pesticides, dyes, synthetic rubber, disinfectants, lacquers and varnishes, photographic chemicals, and room air deodorizers.[3] Acetaldehyde has also been used in hydraulic fracturing fluids.[4]

Canadian Production and Trade

According to TradeMap, there were no reported imports or exports of acetaldehyde in Canada from 2001 to 2007.[38] Camford services reported that 62,250 tonnes of acetaldehyde were imported from the US in 2002, the highest amount reported since 1988.[25]

Until 2002, when production was phased out, one Canadian company produced 1,500 tonnes of acetaldehyde per year. It was used mainly to produce alkyd resins and pentaerythritol.[25]

Production and Trade

Activity Quantity Year
Canadian Production 0.5 kt 2001[39]
Domestic consumption 60 t 2005
(forecasted)[39]
t = tonne
kt = kilotonne

Environmental Exposures

In the environment, inhalation is the most important route of exposures to acetaldehyde.[1] A significant source of inhalation exposure to the general population is biomass combustion, which is typically higher in urban areas (from vehicles, industrial burning, forest fires, and cigarette smoke).[1,3] CAREX Canada estimates that the acetaldehyde levels in outdoor air do not result in higher risk of cancer at a population level (low data quality). However, results show that acetaldehyde levels in indoor air do result in an increased risk of cancer (moderate data quality).

Canadian studies in Prince Edward Island and Saskatchewan measured indoor air concentrations of several compounds, including acetaldehyde, and found that smoking was a significant source of acetaldehyde in homes. This was the case especially when air exchange rates were lower.[38,40] Cooking with oil was also associated with increased levels of acetaldehyde indoors.[40]

Acetaldehyde, along with several other volatile organic compounds, is released from common building materials such as engineered wood products typically used in manufactured homes. This creates potential for exposure to inhabitants of these homes.[41]

A review of acetaldehyde toxicity from the Government of California published in 2008 lists several studies from the last 15-20 years where measurements of acetaldehyde were taken in residences as well as portable classrooms.[42] According to this review, indoor measurements of acetaldehyde usually greatly exceed outdoor measurements.

Acetaldehyde is a metabolic intermediate in humans and other organisms. It is also found naturally in some foods in trace amounts, especially after cooking, ripening of fruit, or fermentation (i.e. in beer and wine).[25] The largest source of exposure to acetaldehyde in the general population is technically via alcohol consumption, where it is produced during alcohol metabolism. However, acetaldehyde is not carcinogenic via ingestion.

Searches of Environment Canada’s National Pollutant Release Inventory (NPRI) and the US Household Products Database yielded the following results on current potential for exposure to acetaldehyde in Canada:

NPRI and US Household Products Database

NPRI 2015[43]
Substance name: ‘Acetaldehyde’
Category Quantity Industry
Released into Environment 668 t Pulp, paper and paperboard mills,
veneer, plywood manufacture,
chemical manufacturing
(61 facilities)
Disposed of 0.024 t
Sent to off-site recycling None
US Household Products 2016[44]
Results: 13 products
Search Term Quantity Product Type
‘Acetaldehyde’ 13 Arts & crafts adhesives (5), home adhesives (5),
landscape adhesive(1); powdered roof leveler (1);
automotive products (1)
t = tonne

For more information, see the environmental exposure estimate for acetaldehyde. 

Occupational Exposures Overview

Inhalation is the most important route of occupational exposure.[1] CAREX Canada estimates that approximately 8,600 Canadians are exposed to acetaldehyde in the workplace. By industry, the largest exposed groups are plastic products manufacturing, food manufacturing, and farming. By occupation, the greatest exposures occur among plastic machine operators, followed by farmers, farm managers, and rubber and plastic manufacturing labourers.

In food manufacturing, workers are exposed to acetaldehyde during diacetyl production. Diacetyl is a substance used for food flavouring, especially in microwave popcorn. Recent studies from the Netherlands[38] and the US[41] have measured acetaldehyde exposure during production of diacetyl.

Because acetaldehyde is also a combustion product, exposure in the petroleum, transportation, waste burning, fire fighting, and wood products industries is also possible.[3]

For more information, see the occupational exposure estimate for acetaldehyde.

Sources

1. National Toxicology Program (NTP). 14th report on carcinogens for Acetaldehyde (2016) (PDF)
2. International Agency for Research on Cancer (IARC). Monograph summary, Volume 71 (1999) (PDF)
3. Environment Canada and Health Canada. Priority Substances List assessment report (CEPA) for Acetaldehyde (2000) (PDF)
4. US National Library of Medicine. Household Products Database (US) (Search term: ‘Acetaldehyde’)
10. Government of Newfoundland and Labrador. Regulation 5,12 Occupational Health and Safety Regulations (2012)
11. Government of the Northwest Territories. Occupational Health and Safety Regulations, R-039-2015 (2016) (PDF)
13. The Canadian Legal Information Institute (CanLII). Government of Nunavut’s Occupational Health and Safety Regulations, Nu Reg 003-2016 (2010)
15. Government of Prince Edward Island. Occupational Health and Safety Act Regulations Chapter 0-1 (2013) (PDF)
17. Government of Saskatchewan. The Occupational Health and Safety Regulations, 1996 (2016) (PDF)
18. The Canadian Legal Information Institute (CanLII). Yukon’s Occupational Health Regulations, O.I.C. 1986/164 (2012) (PDF)
19. Occupational Safety and Health Administration (OSHA). Annotated PELs (2018)
21. Ontario Ministry of the Environment and Climate Change. Ontario’s Ambient Air Quality Criteria (2016)
22. Alberta Environment and Parks. Ambient Air Quality Objectives (2017)
23. Government of British Columbia. Contaminated Sites Regulation B.C. Reg. 375/96 (2017)
25. Government of Canada. List of Permitted Food Additives (2017)
26. Health Canada. Cosmetic Ingredient Hotlist (2014)
27. The Canadian Legal Information Institute (CanLII). Ontario Drinking Water Quality Standards, O Reg 169/03 (2017)
28. The Canadian Legal Information Institute (CanLII). Regulation respecting the quality of drinking water, CQLR c Q-2, r 40 (2016)
29. Health Canada. Prioritization of the DSL (2006)
30. Environment and Climate Change Canada. CEPA List of Toxic Substances (2016)
31. International Joint Commission. Revised Great Lakes Water Quality Agreement of 1978 (1978) (PDF)
32. Canadian Council of Ministers of the Environment (CCME). National Classification System for Contaminated Sites (2008) (PDF)
37. Camford Information Services. CPI Product Profiles: Acetaldehyde (2003)
38. Gilbert NL, Guay M, David Miller J, Judek S, Chan CC, Dales RE. “Levels and determinants of formaldehyde, acetaldehyde, and acrolein in residential indoor air in Prince Edward Island, Canada.” Environ Res 2005; 99(1):11-17.
39. International Trade Centre. TradeMap (Free subscription required)
40. Héroux ME, Clark N, Van Ryswyk K, Mallick R, Gilbert NL, Harrison I, Rispler K, Wang D, Anastassopoulos A, Guay M, MacNeill M, Wheeler AJ.“Predictors of indoor air concentrations in smoking and non-smoking residences.” Intern Journ of Environ Res and Pub Health 2010;7(8):3080-99.
41. Hodgson AT, Beal D, McIlvaine JE. “Sources of formaldehyde, other aldehydes and terpenes in a new manufactured house.”Indoor Air 2002;12(4): 235-242.
42. Office of Environmental Health Hazard Assessment. Draft Acetaldehyde Reference Exposure Levels (2008) (PDF)
43. Environment and Climate Change Canada. National Pollutant Release Inventory (NPRI) Facility Search (Substance name: ‘Acetaldehyde’)
44. US Household Products Database. Household Products (Search term: ‘Acetaldehyde’)

Other Resources

  1. International Programme for Chemical Safety (IPCS) INCHEM. WHO 1995: Acetaldehyde

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