CAREX Canada

Full Profile

CAS No. 8007-45-2 (Coal tar)
CAS No. 65996-93-2 (Coal-tar pitches)

Photo: Wikimedia Commons ^[19]

IARC Monograph Vol. 35, Suppl. 7, 1987 (Group 1)

IARC Monongraph Vol. 100F, 2011. (Group 1)

General Information

Coal tar is produced as a by-product when coal is carbonized to make coke or gas. Distillation of coal tar produces coal tar creosotes as a distillation product, and coal-tar pitch as a distillation residual.^[1] Coal tars are viscous and slightly soluble in water, while coal-tar pitches can be semi-solid to solid.^[2] Coal tars and coal-tar pitches are complex mixtures containing over 400 identified compounds including hydrocarbons, phenols and heterocyclic compounds.^[1] They have many uses industrially and in consumer products. Coal-tar pitch volatiles (CTPVs), containing varying concentrations of Polycyclic Aromatic Compounds (PAHs) are released when coal-tar pitch is heated.^[3] Creosotes are oily liquids used extensively in wood preservation; please consult the separate Creosotes profile for more on this substance. Further substances related to coal tar and coal-tar pitches also considered by CAREX Canada are Bitumens, Benzene, and Naphthalene.

Coal tar and coal-tar pitches have been classified by IARC as Group 1, carcinogenic to humans, with an established link to skin cancer, including scrotal cancer.^[4] A recent IARC review reaffirmed this classification,^[12] citing "sufficient evidence in humans" for a causal relationship between exposure to coal-tar pitch in paving and roofing and lung cancer, as well as "limited evidence in humans" for bladder cancer.^[12] Coke production and coal gasification were also classified as Group 1, based on lung cancer outcomes.^[12] There is also evidence linking coal tar and coal-tar pitches to kidney, bladder and digestive tract cancers, and leukemia.^[1]

Additional adverse health outcomes of coal tar and coal-tar pitches include skin, eye and respiratory tract irritation.^[3]

Coal tar and coal-tar pitches have 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) for coal-tar pitch volatiles

Canadian Jurisdictions	OEL (mg/m³)
Canada Labour Code	0.2
BC, AB, MB, ON, NL, PE, NB, NS, YT	0.2
SK, NT, NU	0.2 0.6 [stel]
QC	0.2 [em]
Other Jurisdiction	OEL (mg/m³)
ACGIH 2011 TLV	0.2

mg/m³ = milligrams per cubic meter

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

em = exposure must be reduced to the minimum

Canadian Environmental Guidelines

Jurisdiction	Limit	Year
Cosmetics Hotlist	'Coal tar dye' – Permitted, with conditions 'Coal tars (crude and refined)' – Not permitted	2011^[5]

Coal tar and coal-tar pitches were not included in other Canadian government environmental guidelines reviewed.^[6-8]

Canadian Agencies/Organizations

Agency	Designation/Position	Year
Health Canada	DSL – high priority substance with greatest potential for exposure	2006^[9]
CEPA	Entry for 'PAHs' only	1999^[10]

Coal tar was not included in other Canadian government chemical listings reviewed.^[11]

Main Uses

The majority of coal tar is distilled to produce refined products, including creosote, coal-tar pitch, crude naphthalene, and anthracene oils. Some crude coal tar is used as fuel for blast furnaces in the steel industry, because of its high availability and heating value.^[2] Coal tar also has a long history of being used in pharmaceutical products for the treatment of skin conditions, including eczema, psorasis and dandruff, and is used in denatured alcohol.^[2]

Coal-tar pitches have primarily been used in industry as the binder for aluminum smelting electrodes.^[3] Coal-tar pitches are also used in roofing materials, surface coatings and for pitch coke production.^[3]

Coal tar and coal-tar pitches are used in surface coating formulations and may also be found in animal and bird repellents, animal dips and insecticides or fungicides.^[3]

Canadian Production and Trade

In 2007, Canada produced 69.5 million tons of coal, making it the 13th largest producer in the world.^[13] Most coal produced, however, is not used in coke production, as 85% of coal consumed in Canada in 2007 was used to generate electricity.^[13]

The amount of coal tar and coal-tar pitch produced from coal was not identified. With coal tar as a by-product, metallurgical use—i.e. coking for the steel industry—accounted for the second largest use.^[13] Ontario is the main provincial consumer of coal for coke production.^[13]

Production and Trade

Activity	Quantity	Year
Domestic Coal Consumption	58,000,000 t	2007^[13]
Export: Mainly to US	155,363 t of ‘oils and other products of the distillation of high temperature coal tar’	2010^[14]
Export: Mainly to US	62,324 t of ‘pitch and pitch coke’	2010^[14]
Import: Mainly from US	110,165 t of 'oils and other products of distillation of high temperature coal tar'	2010^[14]
Import: Mainly from Colombia	23,001 t of 'pitch and pitch coke'	2010^[14]

t = tonne

Occupational Exposures

Inhalation and dermal contact are the most important routes of occupational exposure.^[2]

Industries with potential for occupational exposure to coal tar and coal-tar pitch include those associated with coke production, coal gasification, steel foundries, aluminum smelting, construction, and during installation of electrical equipment.^[1,2] Exposure may occur during production or use of pavement or roofing tar, coal-tar pitch, refractory bricks, paints, enamels, or coatings.^[1]

Environmental Exposures

Inhalation, dermal contact and ingestion are all potential routes of exposures for the general public.^[1]

The use of pharmaceutical products (lotions and ointments) to treat skin disorders (e.g. psoriasis), and shampoos used for dandruff are common exposure sources.^[1] In Canada, anti-dandruff products are classified as drugs if they contain coal tar at concentrations of 0.5-10%.^[15]

Environmental contamination from living near factories or plants that use coal tar or coal-tar pitches is a potential source of exposure.^[4] Twenty-five former coal tar/creosote production sites in Ontario were recently tested and shown to have persistent subsurface occurrence of coal tar.^[2] Most of the sites had not been engaged in active production for over 35 years.^[2]

In 1999, the city of Kingston in Ontario undertook a large clean up of its former coal gasification site which ran until the late 1950s. Large quantities of soil and groundwater contaminated with coal tar were removed to prevent further exposures to the public; not all of the contamination could be removed.^[16]

Some components of coal tar and coal-tar pitch are expected to bioaccumulate in aquatic species.^[3]

Searches of a US consumer product database yielded the following results on current potential for exposure to coal tar & coal-tar pitches in Canada:

US Household Products Database

US Household Products 2010^[18]
Search Term	Quantity	Product Type
'coal-tar pitch'	4	Sealants, pet shampoo
'refined coal-tar pitch'	2	Driveway sealants

Releases of coal tar and coal-tar pitches are not reportable to Environment Canada's National Pollutant Release Inventory (NPRI).^[17]

Sources

Other Resources

Published March 2012

Coal Tar and Coal-Tar Pitches