CAREX Canada

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CAS No. 1314-62-1

Photo: Wikimedia Commons^[1]

IARC Monograph Vol. 86, 2006 (Group 2B)

General Information

The most common form of vanadium is vanadium pentoxide (V₂O₅), which is a yellow-red crystalline powder.^[2] Vanadium is a soft grey metal, but is more commonly found in nature in compounds with oxygen, sodium, sulphur, or chloride and may be found in rocks, iron ores, and petroleum deposits.^[3] Vanadium oxides are released from the combustion of vanadium containing ores and petroleum. Vanadium pentoxide may also be referred to as vanadium oxide, divanadium pentoxide, and vanadic acid anhydride. There are numerous other synonyms and product names; see the HSDB for more information.^[4]

Vanadium pentoxide was classified by IARC in 2006 as Group 2B, possibly carcinogenic to humans, with inadequate evidence of carcinogenicity in humans and sufficient evidence in animals.^[5] In one study, inhalation exposure resulted in increased incidence of alveolar/bronchiolar neoplasms in mice and male rats.^[5] No human data on carcinogenicity were available to the IARC working group.

Additionally, V₂O₅ is a respiratory irritant,^[3] and at high doses can cause ‘boilermaker’s bronchitis,’ an acute respiratory irritation.^[5]

Vanadium pentoxide has 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)

Canadian Jurisdictions	OEL (mg/m³)
Canada Labour Code	0.05 [i]
BC	0.2 [total dust] 0.05 [c for r]
AB, QC, ON, NB	0.05 [r]
SK	0.05 [r] 0.15 [stel]
MB, NL, PE, NS	0.05 [i]
NT, NU, YT	0.05 [dust] 1.5 [stel] 0.05 [c] (fume)
Other Jurisdiction	OEL (mg/m³)
ACGIH 2011 TLV	0.05 [i]

mg/m³ = milligrams per cubic meter

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

c = ceiling (not to be exceeded at any time)

r = respirable fraction

i = inhalable fraction

Canadian Environmental Guidelines

Vanadium pentoxide was not included in the Canadian government environmental guidelines reviewed.^[6,7,14,15]

Canadian Agencies/Organizations

Agency	Designation/Position	Year
Health Canada	DSL – high priority substance with the greatest potential for exposure	2006^[8]
CMP Challenge	Batch 9B for 'vanadium oxide'	2008^[10]

Vanadium pentoxide was not included in other Canadian government chemical listings reviewed.^[9]

Main Uses

The primary industrial use of vanadium pentoxide is in ferrovanadium, which is used in the production of high strength, low alloy steels.^[11] Smaller amounts of vanadium pentoxide are used in titanium-aluminum alloys, with applications in the aerospace industry.^[11] Vanadium compounds are also used in pigments & inks, as colouring agents and to provide UV filtering in some glasses,^[12] as well as in the production of plastics, rubbers, ceramics and other metals.^[3]

Vanadium pentoxide is used as an oxidation catalyst in industrial synthesis processes such as the manufacturing of sulphuric acid,^[12] and for catalytic converters in automobiles.^[4]

A specialty application is in Vanadium Redox Batteries (VRB), which are large-scale electrochemical energy storage systems.^[11] One Canadian company (VRB Power Systems) was working on developing vanadium redox batteries, but it announced that it is curtailing operations (as of November 2008).^[13]

Canadian Production and Trade

Canadian market demands for vanadium pentoxide are primarily met through import.^[11]

Canada has not produced vanadium since the early 1990s, when a vanadium plant closed in Fort McMurray, Saskatchewan. Vanadium was being produced through recovery from oil sands in the form of HVO₃ (they were expecting to produce vanadium pentoxide later), but the operation ceased due to low prices.^[11] China, Russia and South Africa are the leading world producers of vanadium.^[16]

There are three major geological deposits—two in northern Quebec, one in northern Manitoba—which are in relatively early stages of development.^[11]

There is very little recycling of vanadium; most is obtained from primary sources including recovery from ores, concentrates, slags or petroleum residues.^[16]

Production and Trade

Activity	Quantity	Year
Export: Mainly to France	14 t of ‘vanadium oxides and hydroxides’	2010^[17]
Import: Mainly from China, South Africa	1,267 t of 'vanadium oxides and hydroxides'	2007^[17]

t=tonne

Occupational Exposures

Inhalation is the most important route of occupational exposure.^[3]

The main occupations exposed include workers involved in vanadium mining, welding, petroleum refining, cleaning fossil fuel burning furnaces or flues, ceramics making (where vanadium is used as a pigment).^[2] Exposure data and task-related information from the UK are available for boiler and furnace cleaners, catalyst refurbishment, alloy manufacture, and pigment manufacture.^[19]

The production and refining of iron ores often produces a slag rich in vanadium pentoxide, which creates the potential for occupational exposure.^[18] Further, vanadium pentoxide is continuously discharged during the production of ferrovanadium alloys, resulting in exposures to smelter workers.^[5]

Environmental Exposures

Although food is typically the main source of exposure to vanadium compounds, they are poorly absorbed through the gastrointestinal system.^[3] Soil contamination on food can contribute to exposure since soil concentrations can be much higher than air levels, especially near metallurgical plants or other sources.^[3] High soil levels are particularly relevant in children prone to ingesting soil.^[3]

For people living near a point source, ambient air will be the primary exposure source to vanadium pentoxide.^[3] The most significant source of vanadium-contaminated air is oil and coal combustion (90% of total global emissions).^[5,12] Levels of vanadium are typically higher near metallurgical plants and in large cities (especially on the heavily-populated eastern seaboard of the US and Canada, where the burning of fuel oils is common in the cold months).^[5] Ambient levels may be elevated in port cities due to high levels of vanadium emitted from ships using heavy fuel oil.^[20]

Vanadium has been measured in samples of coal and ash from Canadian sources.^[21] No household products are listed for vanadium pentoxide in the Household Products Database from the United States.^[22]

A searches of an environmental emission database yielded the following results on current potential for exposure to vanadium pentoxide in Canada:

NPRI Reported Releases

NPRI 2009^[23]
Search term: 'vanadium (except when in alloy) and its compounds
Category	Quantity	Industry
Released into Environment	94 t	Oil and gas, waste management, and power generation (108 companies)
Disposed of	9,947 t
Sent to off-site recycling	1,631 t