CAS No. 8007-45-2 (Coal tar) CAS No. 65996-93-2 (Coal-tar pitches)
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IARC Monograph Vol. 35, Suppl. 7, 1987 (Group 1)
IARC Monongraph Vol. 100F, 2011. (Group 1)
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. Coal tars are viscous and slightly soluble in water, while coal-tar pitches can be semi-solid to solid. Coal tars and coal-tar pitches are complex mixtures containing over 400 identified compounds including hydrocarbons, phenols and heterocyclic compounds. 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. 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. A recent IARC review reaffirmed this classification, 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. Coke production and coal gasification were also classified as Group 1, based on lung cancer outcomes. There is also evidence linking coal tar and coal-tar pitches to kidney, bladder and digestive tract cancers, and leukemia.
Additional adverse health outcomes of coal tar and coal-tar pitches include skin, eye and respiratory tract irritation.
Occupational Exposure Limits (OEL) for coal-tar pitch volatiles
Canada Labour Code
AB, BC, MB, NB, NL, NS, ON, PE
SK, NT, NU
0.2 0.6 [stel]
ACGIH 2014 TLV
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
'Coal tar dye' – Permitted, with conditions 'Coal tars (crude and refined)' – Not permitted
Ontario Ambient Air Quality Criteria
Coal tar pitch volatiles - soluble fraction 24-hour 1 µg/m3
µg/m3 = micrograms per cubic meter
Coal tar and coal-tar pitches were not included in other Canadian government environmental guidelines reviewed.[6-8]
DSL – high priority substance with greatest potential for exposure
Entry for 'PAHs' only
Coal tar was not included in other Canadian government chemical listings reviewed.
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. 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.
Coal-tar pitches have primarily been used in industry as the binder for aluminum smelting electrodes. Coal-tar pitches are also used in roofing materials, surface coatings and for pitch coke production.
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.
Canadian Production and Trade
In 2009, Canada produced 63 million tons of coal, a 7.7% decrease from 2008, with the majority of decline attributable to coking coal (steam coal production remained relatively constant) . Most coal produced, however, is not used in coke production, as 88% of coal consumed in Canada in 2008 was used to generate electricity.
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 . Ontario is the main provincial consumer of coal for coke production.
Production and Trade
Domestic Coal Consumption
Export: Mainly to US
155,363 t of ‘oils and other products of the distillation of high temperature coal tar’
Export: Mainly to US
62,324 t of ‘pitch and pitch coke’
Import: Mainly from US
110,165 t of 'oils and other products of distillation of high temperature coal tar'
Import: Mainly from Colombia
23,001 t of 'pitch and pitch coke'
t = tonne
Inhalation and dermal contact are the most important routes of occupational exposure. CAREX Canada estimates that approximately 7,600 Canadian workers are exposed to coal tar and coal-tar pitches in their workplace.
Among Canadian industries, the largest exposed industrial groups are alumina and aluminum production and processing; foundation, structure, and building contractors; and highway, street, and bridge construction. In terms of occupations, the largest exposed groups are roofers and shinglers, followed by construction trades helpers and labourers, and machine operators in mineral and metal processing.
Other industries with potential for occupational exposure to coal tar and coal-tar pitch include those associated with coke production, coal gasification, steel foundries and during installation of electrical equipment.[1,2] Exposure may also occur during production or use refractory bricks, paints, enamels, or coatings.
Inhalation, dermal contact and ingestion are all potential routes of exposures for the general public.
The use of pharmaceutical products (lotions and ointments) to treat skin disorders (e.g. psoriasis), and shampoos used for dandruff are common exposure sources. In Canada, anti-dandruff products are classified as drugs if they contain coal tar at concentrations of 0.5-10%.
Environmental contamination from living near factories or plants that use coal tar or coal-tar pitches is a potential source of exposure. Twenty-five former coal tar/creosote production sites in Ontario were recently tested and shown to have persistent subsurface occurrence of coal tar. Most of the sites had not been engaged in active production for over 35 years.
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.
Some components of coal tar and coal-tar pitch are expected to bioaccumulate in aquatic species.
Releases of coal tar and coal-tar pitches are not reportable to Environment Canada's National Pollutant Release Inventory (NPRI). 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 2013
Sealants, pet shampoo
'refined coal-tar pitch'
Our team has performed a detailed scan of exposure control resources and assembled a compilation of key publications and resources. These are organized by type of exposure (environmental or occupational) and by specificity (general or carcinogen-specific). Please visit our Exposures Reduction Resources page to view.
We also recommend exploring the Prevention Policies Directory, a freely-accessible online tool offering information on policies related to cancer and chronic disease prevention. Providing summaries of the policies and direct access to the policy documents, the Directory allows users to search by carcinogen, risk factor, jurisdiction, geographical location, and document type. Click here to learn more about policies specific to coal tar and coal tar pitches in the Directory. For questions about this resource, please contact a member of the Prevention Team at the Canadian Partnership Against Cancer at email@example.com.