1,2-Dichloropropane Profile

INDUSTRIAL CHEMICALS  KNOWN CARCINOGEN (IARC 1)

CAS No. 78-87-5
IARC Monograph Vol. 41, Suppl. 7, 1986 (Group 3)
IARC Monograph Vol. 71, 1999 (Group 3)
IARC Monograph Vol. 110, 2016 (Group 1)

1,2-Dichloropropane Profile

General Information

1,2-Dichloropropane (1,2-DCP), also known as propylene dichloride, is a colourless, flammable liquid that smells like chloroform. 1,2-DCP is used as a chemical intermediate to produce other organic compounds including perchloroethylene, propylene, carbon tetrachloride, and tetrachloroethylene.[1,2] Up until the 1980s in Canada, it was sold in a mixture with 1,3-dichloropropene as a soil fumigant (major trade names: D-D mixture®, Nemafene®, Vidden-D®).[3,4] It was also found in industrial solvents and paint strippers, varnishes, and furniture finish removers.[5]

The International Agency for Research on Cancer (IARC) classified 1,2-DCP as carcinogenic to humans (Group 1) in 2014.[1] Two studies examining exposure to 1,2-DCP in a Japanese printing plant in Osaka found an extremely high associated risk of a very rare bile duct cancer (17 of 111 workers were diagnosed).[6,7] IARC found that these two studies provided sufficient evidence for a causal association between 1,2-DCP and bile duct cancer.[1] Sufficient evidence for carcinogenicity was also reported in experimental animals, where malignant lung and liver tumors were observed in exposed mice.[1]

Acute exposure by intentionally or accidentally consuming or inhaling 1,2-DCP has resulted in dizziness, headache, nausea, injury to liver and kidneys, anemia, coma, and death.[3] Occupational exposures may lead to skin sensitization and dermatitis.[8]

Regulations and Guidelines

Occupational Exposure Limits (OEL) [9,10,11,12,13,14,15,16,17,18,19,20,21,22,23]

Canadian Jurisdictions OEL (ppm) Notes
Canada Labour Code 10 Follows ACGIH’s TLV-TWA; s
AB 10 TWA
BC 75
110
TWA; dsen
[stel]
NU, QC, SK 75
110
TWA
[stel]
MB, NL, NS, PE 10 Follows ACGIH’s TLV-TWA; s
NB 75
110
TWA
[stel]
Follows ACGIH’s 1994 TLV
ON 10 TWA
NT, YT 75
115
TWA
[stel]
Other Jurisdiction OEL (ppm) Notes
ACGIH 2018 TLV 10 TWA; s
ppm = parts per million
ACGIH = American Conference of Governmental Industrial Hygienists
TLV = threshold limit value
TWA = time weighted average (8 hours)
s = sensitizer (a substance that stimulates an immune reaction; subsequent exposures result in intense responses, even at exposures below the TLV)
dsen = dermal sensitizer
stel = short term exposure limit (15 min. maximum)

Canadian Environmental Guidelines

Jurisdiction Limit Year
Canadian Council of Ministers for the Environment (CCME) National Classification System for Contaminated Sites Rank: “High priority”; no guideline developed 2008[24]
Ontario Ambient Air Quality Criteria 2400 µg/m3 2016[25]
Environment Canada’s National Pollutant Release Inventory Listed under Part 1A: Threshold Category. Reportable to NPRI if manufactured, processed, or otherwise used at quantities greater than 10 tonnes 2016[26]
BC’s Contaminated Sites Regulation, BC Reg 375/96 Sets vapour standards for the protection of human health:
Agricultural, urban park, residential use standard: 4 μg/m3
Commercial use standard: 10 μg/m3
Industrial use standard: 35 μg/m3
Parkade use standard: 30 μg/m3
2017[27]
WHO Drinking Water Guideline 0.04 mg/L (provisional guideline value) 2011[28]
 
1,2-DCP was not included in other Canadian government environmental guidelines reviewed.[24,29,30,31,32,33,34]

Canadian Legal Status[35]

Jurisdiction Legislation Notes
Federal Pest Control Products Act, SC 2002, c 28 1,2-DCP is not registered for use as a pesticide
Provincial/Territorial    
AB, BC, MB, NB, NL, NS, NT, NU, PE, QC, SK, TY Apart from the established OELs, legislation specific to 1,2-DCP has not been passed
ON Air Pollution – Local Air Quality, O Reg 419/05 Prohibited discharge of 1,2-DCP into the air if the concentration of 1,2-DCP exceeds the half hour standard of 2,400 µg/m3

Main Uses

1,2-DCP is a synthetic chemical and a byproduct in producing epichlorohydrin. Currently, the major use of 1,2-DCP is as an intermediate for producing organic compounds.[3,36] Other functions include: a solvent in paint, varnish, and furniture finish removers; a lead scavenger in gasoline additives such as anti-knock fluids; a dry cleaning fluid; a paint remover; and a metal degreaser. 1,2-DCP is also used to make and convert rubber, prepare scouring compounds, and produce photographic film.[36] In many of these cases, 1,2-DCP has now been replaced by other compounds.[3]

In the past, 1,2-DCP was formulated with 1,3-dichloropropene in a formulation called D-D mixture that was used to fumigate soil and grain. Formulations containing 1,2-DCP were effective against soil nematodes, and were applied to a number of different crops including wheat, canola, sugar beets, and others.[36] 1,2-DCP has not been used as a soil fumigant in Canada since the 1980s,[4] and it is currently not registered for use as a pesticide under the Pest Control Act.[37]

Canadian Production and Trade

The total global production volume of 1,2-DCP was estimated at 350,000 tonnes for 2001.[36] Major producers of 1,2-DCP at that time were located in India, Germany, and the United States.[36] By 2009, the amount of 1,2-DCP produced in the United States had decreased considerably, but the total amounts of 1,2-DCP disposed were still substantial, at approximately 200 tonnes.[38]

Production and trade information for 1,2-DCP specific to Canada is scarce. Results from the second Domestic Substances List Inventory Update indicate that between 100 to 999 kg of 1,2-DCP was imported during 2011 as an intermediate compound for paper products, mixtures, or manufactured items.[39]

Environmental Exposures Overview

1,2-DCP is a synthetic chemical and its presence in the environment is the direct result of anthropogenic activity. For example, 1,2-DCP is released into wastewater by industries that use it as a solvent. This occurs in the manufacture of ion exchange resins.[3]

In groundwater, 1,2-DCP may persist for a long time.[3] It is very resistant to degradation in soil; one study showed that after 12 weeks in a closed system, 98% of the initial amount of 1,2-DCP applied could be recovered.[40]

Exposure to 1,2-DCP in the general population may occur by inhaling contaminated air or consuming contaminated drinking water.[3] According to the National Pollutant Release Inventory, there were no on-site releases of 1,2-DCP to the air by industry in Canada in 2010 and 2014.[41] However, exposure to 1,2-DCP may arise when shallow groundwater gets contaminated by soils to which 1,2-DCP had been historically applied and then desorbed. Contamination can also take place when currently-used fumigants, such as 1,3-dichloropropene, contain trace amounts of 1,2-DCP.[42] For example, 1,2-DCP was detected in 56% of wells sampled in Southwestern BC in 1997-1998.[42] However, since 1,2-DCP is no longer used as a soil fumigant and in commercial products in Canada and the United States, environmental exposure is expected to be low.

Occupational Exposures Overview

The main routes of occupational exposure are through inhalation and dermal pathways.[43] People who produce 1,2-DCP, use it in chemical reactions, or use it as an industrial solvent have the greatest potential for exposure.[44,45]

Canadian occupational exposure data is limited. In the 1981-1983 National Occupational Exposure Survey, the National Institute for Occupational Safety and Health estimated that 2,944 workers, not including farmers, were potentially exposed to 1,2-DCP in the United States.[8] Dow Chemical Company, a major manufacturer of 1,2-DCP, estimated that 45 to 123 workers were routinely and potentially exposed to the chemical in the 1980s.[3] However, because the conversion and disposal of 1,2-DCP occurs in closed systems, Dow Chemical Company asserts that the current level of exposure is minimal.[3]

Exposure to 1,2-DCP in its solvent form increases with poor ventilation and lack of respiratory protective equipment. This is illustrated in the studies IARC reviewed on the Japanese printing plant where exposures were 19 to 33 times the occupational exposure limit set by the Canadian Labour Code.[6,7] Other printing plants in Japan with poor ventilation were estimated to result in similar, or even higher levels of exposure.[46] Such high exposure levels are unlikely to occur in Canadian workplaces since 1,2-DCP is not used as a solvent.[39]

CAREX Canada has not prioritized 1,2-DCP for exposure estimate development. This is because there is a lack of exposure monitoring data in the Canadian Workplace Exposure Database on which to base an estimate.

Sources

1. International Agency for Research on Cancer (IARC). IARC Monographs Volume 110 (2016) (PDF)
2. Agency for Toxic Substances and Disease Registry (ATSDR). Toxic Substances – 1,2-Dichloropropane (2011)
3. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological profile for 1,2-Dichloropropane (1989) (PDF)
4. Government of Canada. Contaminants: 1,2-Dichloropropane (2013)
6. Kumagi S, Kurumatani N, Arimoto A, Ichihara G. “Cholangiocarcinoma among offset colour proof-printing workers exposed to 1,2-dichloropropane and/or dichloromethane.” Occup and Environ Med 2013;70:508-5010.
7. Kubo S, Nakanuma Y, Takemura S, et al. “Case series of 17 patients with cholangiocarcinoma among young adult workers of a printing company in Japan.”Journ of Hepato Panc Sci 2014;21:479-488.
8. US National Library of Medicine. Hazardous Substances Data Bank (HSDB). (1986) (Search term: 1,2-Dichloropropane)
14. Government of Newfoundland and Labrador. Regulation 5,12 Occupational Health and Safety Regulations (2012)
15. Government of the Northwest Territories. Occupational Health and Safety Regulations, R-039-2015 (2016) (PDF)
17. The Canadian Legal Information Institute (CanLII). Government of Nunavut’s Occupational Health and Safety Regulations, Nu Reg 003-2016 (2010)
19. Government of Prince Edward Island. Occupational Health and Safety Act Regulations Chapter 0-1 (2013) (PDF)
21. Government of Saskatchewan. The Occupational Health and Safety Regulations, 1996 (2016) (PDF)
22. The Canadian Legal Information Institute (CanLII). Yukon’s Occupational Health Regulations, O.I.C. 1986/164 (2012) (PDF)
23. Occupational Safety and Health Administration (OSHA). Annotated PELs (2018)
24. Canadian Council of Ministers of the Environment (CCME). National Classification System for Contaminated Sites (2008) (PDF)
25. Ontario Ministry of the Environment and Climate Change. Ontario’s Ambient Air Quality Criteria (2016)
27. Government of British Columbia. Contaminated Sites Regulation B.C. Reg. 375/96 (2017)
29. Government of Canada. List of all Challenge Substances (2009)
30. Government of Canada. Toxic Substances List – Schedule I (2013)
32. International Joint Commission. Revised Great Lakes Qater Quality Agreement of 1978 (1978) (PDF)
35. The Canadian Legal Information Institute (CanLII). Canadian Legal Information Institute, CanLII
36. Organisation for Economic Co-operation and Development (OECD). 1,2-Dichloropropane. UNEP Publications (2003) (PDF)
38. US Environmental Protection Agency (EPA). Toxics Inventory Program (2009)
42. Tesoriero AJ, Loffler FE, Liebscher H. “Fate and origin of 1,2-dichloropropane in an unconfined shallow aquifer.” Environ Sci and Tech 2001;35:455-461.
43. Wisconsin Department of Health Services. 1,2-Dichloropropane (2015)
44. Agency for Toxic Substances and Disease Registry (ATSDR). 1,2-Dichloropropane Fact Sheet (1999) (PDF)
45. US Environmental Protection Agency (EPA). Propylene Dichloride (1,2-Dichloropropane) Hazard Summary (2000) (PDF)
46. Kumagai S. “Two offset printing workers with cholangiocarcinoma.” Journ of Occup Health 2014;56:164-168.

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