Creosotes

Full Profile

General Information

“Creosotes” most commonly describes a group of complex and variable mixtures made from the distillation of coal and containing more than 300 compounds.^[2] Creosotes derived in this way are often referred to as coal-tar creosotes and are used to protect wood from fungi, insects and marine organisms.

Wood creosotes are a separate group of chemicals derived from the resin of the leaves of the creosote bush, or from beechwood.^[3] Wood creosotes are not considered in this profile, as they are not chemically related to coal-based creosotes. Other substances related to creosotes that are under consideration by CAREX Canada are Polycyclic Aromatic Hydrocarbons (PAHs) and Coal-tar & Coal-tar Pitches; these profiles may be consulted for further information.

Coal-tar creosote is primarily composed (up to 90%) of PAHs, with small amounts of phenolics and nitrogen-, sulphur-, and oxygen-containing heterocyclics.^[2]

Creosotes derived from coal-tars have been classified by IARC as Group 2A, probably carcinogenic to humans, based on sufficient evidence in animals and limited evidence in humans.^[4,5] Creosotes are skin and lung carcinogens in mice.^[4] Human evidence suggests a link between creosote exposure and skin cancer (especially scrotal), but there have been only a few small studies.^[4]

Exposure to creosotes can cause irritation of the skin and respiratory tract.^[3]

Creosotes have been ranked by CAREX Canada as a Group A priority (immediate high priority) for occupational settings and as a Group B priority (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

No occupational exposure limits for creosotes were found in ACGIH or Canadian OEL guidelines.

Canadian Environmental Guidelines

Jurisdiction	Limit	Year
Cosmetic Ingredients Hotlist	Not Permitted	2011[13]

Creosote was not included in other Canadian government environmental guidelines reviewed.^[6,7,14]

Canadian Agencies/Organizations

Agency	Designation/Position	Year
Health Canada	DSL – high priority substance with lowest potential for exposure	2006[8]
CEPA	Schedule 1, paragraph ‘a’	1999[9]

Creosote was not included in other Canadian government chemical listings reviewed.^[15]

Main Uses

Coal tar creosotes are primarily used as a heavy-duty wood preservative on railroad ties, fence posts, marine pilings, utility poles, and outdoor lumber.^[3] The service life of creosote-treated wood products is estimated by industry users to be 40 to 50 years.^[10]

Canadian Production and Trade

Canada is the second largest producer of treated wood (second to the USA and equal to the UK).^[11] In 1999, Canada produced nearly 3.5 million cubic meters of treated wood; about 6% of the wood was treated with creosotes.^[11] In 2006, analysis of the Canadian treated wood industry predicted that production will remain stable for the foreseeable future.^[11] Approximately 13% of domestically consumed wood products are treated, but only 4% of the production total is treated because most is exported.^[11]

In 2003, creosote was the most commonly used pesticide in British Columbia. About 2,200 tonnes of creosotes were sold in BC that year, constituting 47% of all pesticides used.^[16]

Since 2007 Ontario has used 3.6 million cubic metres of creosote-treated wood containing 179,891 tonnes of creosote.^[10] 89% of the treated wood was used for railway ties, 8% for treated utility poles, and 3% for highway structures.

In 2008, there were 5 creosote treatment plants across Canada in Nova Scotia, Quebec, and British Columbia.^[10] There have been no operating wood treatment plants in Ontario since the Thunder Bay Plant closure in 2002.^[10]

Production and Trade

Production	Quantity	Year
Creosote-treated wood (total)	206,592 m3	1999[17]
Lumber, timber, and plywood	11,405 m3
Posts	None
Poles and piling	27,037 m3
Ties	166,677 m3
Treating services only	1,474 m3
Activity	Quantity	Year
Export: Mainly to US	1,011 t of ‘creosote’	2010[18]
Import: Mainly from US	761 t of ‘creosote’	2010[18]

Occupational Exposures

The most important routes of occupational exposure are inhalation and dermal.^[4] The main occupations with the potential for exposure to creosotes include workers in wood preservation and processing, lumber treatment and inspection, fence and bridge construction, railroad workers, electric utility work involving treated poles, and site remediation work involving creosote contamination.^[3]

In Canada, the wood treatment industry provided employment for 5,268 workers in 1992 and 7,440 workers in 1999.^[17]

Environmental Exposures

Sources of environmental exposure include drinking contaminated water, contact with creosote-treated scrap lumber, use of creosote treated materials, and living in houses built with creosote treated wood.^[3]

In Canada creosote-impregnated waste materials arise from two sources: creosote waste products (i.e. railway ties), which accounts for 71% of waste materials by weight, and creosote-contaminated sites (i.e. where creosote is found in soils or groundwater), which accounts for 29% of waste material.^[2]

In Canada, railway ties are the largest creosote waste product by volume. Every year the major railways decommission 4.5 million ties which contain an estimated 20,000 tonnes of creosote.^[2] Approximately 90% of all railway ties are reused leaving approximately 2,000 tonnes of creosote per year as waste.

In 2008, Ontario’s pattern of creosote disposal methods was as follows: 66% sent to the US for incineration (railway ties only), 26% sent to landfills, 8% sent to reuse/recycling.^[10] Open burning and sale to third parties is not practiced. Other creosote waste products are generated from decommissioned docks, breakwaters, railway trestles and bridges.^[2]

In 2002, 11 abandoned or operating creosote-treating facilities in Canada were responsible for moderate to highly contaminated soil. In all, there were 24 known creosote-contaminated sites across all provinces at that time (except PEI).^[2] Groundwater was severely contaminated at several sites.

Sources

1. Wikimedia Commons Photos: Creosotes
2. Priority Substances List Assessment report (CEPA) for Creosote-impregnated waste materials (1993) (PDF)
3. ATSDR Toxicological Profile for Wood Creosote, Coal Tar Creosote, Coal Tar, Coal Tar Pitch, and Coal Tar Pitch Volatiles (2002) (PDF)
4. IARC monograph, Supplement 7 (1987) (PDF)
5. IARC monograph summary, Volume 92 (2010) (PDF)
6. Health Canada (2010) Guidelines for Canadian Drinking Water (PDF)
7. Exposure Guidelines for Residential Indoor Air Quality (1987) (PDF)
8. Health Canada’s Prioritization of the DSL
9. CEPA List of Toxic Substances
10. G.E. Brudermann (2008) “An Inventory of Creosote in Ontario”. Report Prepared for Environment Canada, Ontario Region (PDF)
11. Morris P. & Wang J. (2006). Wood Preservation in Canada, Durability and Protection Group: Forintek Canada Corp. (PDF)
12. Pest Management Regulatory Agency (PMRA) List of registered Pesticides
13. Health Canada (2011) Cosmetic Ingredient Hotlist
14. Health Canada (2006) Food Additives Permitted for Use in Canada
15. Government of Canada (2010) Chemicals Management Plan – List of all Challenge Substances
16. BC Ministry of the Environment, Survey of Pesticide Use in BC (2003) (PDF)
17. Stephens, RW, GE Brudermann, DE Konasewich (2001). Summary of the Results of Environment Canada’s Assessment 2000 program for the Canadian Wood Preservation Industry. Report prepared for Environment Canada.
18. TradeMap (Free subscription required)

Other Resources

1. Wood Preservation Canada (WPC) (formerly the Canadian Institute of Treated Wood)
2. Canadian Wood Preservation Association (CWPA)
3. The Canadian Standards Association (CSA)
4. BC Ministry of Forests and Range Library: Publications of Creosote in BC (Search: ‘creosote’)
5. Concise International Chemical Assessment Document (CICAD) 62: Coal Tar Creosote
6. Government of Canada, Recommendations for the Design and Operations of Wood Preservation Facilities
7. EPA: Preliminary Risk Assessment for Creosote
8. ATSDR ToxFAQs Sheet for Creosote (PDF)