Wood Dust Profile

FIBERS AND DUSTS  KNOWN CARCINOGEN (IARC 1)

CAS No. 
IARC Monograph Vol. 62, 1995 (Group 1)
IARC Monograph Vol. 100C, 2012 (Group 1)

Wood Dust Profile

QUICK SUMMARY

  • A by-product of logs being converted into finished wood products
  • Associated cancers: Cancers of the nasal cavities, paranasal sinuses, and nasopharyngeal region
  • Most important route of exposure: Inhalation
  • Occupational exposures: Approx. 340,000 Canadians are exposed to wood dust at work, primarily in the construction sector
  • Environmental exposures: Via home projects including wood working, arts and crafts, and construction activities
  • Fast fact: Quebec and Ontario produce the majority of hardwood lumber and plywood in Canada, while British Columbia produces primarily softwoods.

General Information

Wood dust, generated through wood processing, is composed of cellulose, polyoses, and lignin compounds.[1] A variety of biologically active, low molecular weight compounds may also be present in wood dust, depending on the species of wood. These compounds include alcohols, terpenes, sterols, glycerols, tannins, flavonoids, quinones, lignans, alkaloids, and proteins.[2]

Tree species are broadly classified into two types: hardwood (angiosperms or deciduous trees such as birch, maple, and oak), and softwood (gymnosperms or conifers such as Douglas fir, spruce, pine, hemlock, and cedar).[3] There are an estimated 12,000 different tree species worldwide.[2]

Wood dust has been classified by the International Agency for Research on Cancer (IARC) as Group 1, carcinogenic to humans. This classification is based on a clear relationship between high levels of wood dust exposure, particularly from hardwood species, and cancers of the nasal cavities, paranasal sinuses, and nasopharyngeal cancer.[1,4] Associations with laryngeal cancer, Hodgkin lymphoma, and other types of cancers have been reported but are not consistent.[1,2,4]

Other adverse health effects of wood dust exposure include eye, nose, and throat irritation from short term exposure.[5] Decreased lung function, increased respiratory symptoms, and allergic reactions are also associated with wood dust exposure. Asthma is typically associated with exposure to western red cedar, eastern white cedar, and many tropical tree species, but has also been linked to other common species such as pine and oak.[4] Skin contact with a variety of species, particularly tropical hardwoods, can cause allergic and/or irritant dermatitis.[5]

Regulations and Guidelines

Occupational Exposure Limits (OEL)[6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]

Canadian Jurisdictions OEL (mg/m3)
Canada Labour Code 0.5 [WRC, i, dsen, rsen]
1 [all other species, i]
BC 1 [allergenic species or non-allergenic hardwood]
2.5 [non-allergenic softwood]
AB 0.5 [WRC]
5 [softwoods and hardwoods except western red cedar]
MB, NL, NS, PE 0.5 [WRC, i, dsen, rsen]
1 [all other species, i]
NB 1 [certain hardwoods, such as beech and oak]
5 [softwood]
10 [softwood, stel]
NT, NU, SK 1 [certain hardwoods such as beech and oak, sen]
3 [Certain hardwoods such as beech and oak, stel]
5 [softwood, sen]
10 [softwood, stel, sen]
ON 1 [certain hardwoods]
5 [softwood]
10 [softwood, stel]
QC 2.5 [WRC, td]
5 [wood dust hard and soft, except WRC, td]
YT 5 [non-allergenic]
10 [non-allergenic stel]
2.5 [allergenic]
5 [allergenic stel]
Other Jurisdiction OEL (mg/m3)
ACGIH 2018 TLV 0.5 [WRC, i, dsen, rsen]
1 [all other species, i]
mg/m3 = milligrams per cubic meter
WRC = western red cedar
i = inhalable fraction
dsen = dermal sensitization
rsen = respiratory sensitization
sen = potential for sensitization
stel = short term exposure limit (15 min. maximum)
td = total dust
ACGIH = American Conference of Governmental Industrial Hygienists
TLV = threshold limit value

Main Uses

Wood dust and other byproducts including wood chips, sawdust, and shavings are produced in the process of converting logs into finished wood products.[3] While some byproducts have end-uses in particle board, as fuel, or for composting, there is no specific use for fine particulate wood dust.[2]

Production in Canada

Lumber is the most significant wood product manufactured in Canada.[3] Less than 40% of the lumber is used domestically, with the majority of exports going to the US and China.[3]

Softwoods are used most frequently in Canadian industry, and account for nearly two-thirds of commercially used woods worldwide.[1,3] The wood products industry consumes approximately half of the round wood cut in Canada; the remainder is used by the pulp and paper industry.[3]

Wood species vary by industry, region, and type of product. Quebec and Ontario produce the majority of hardwood lumber and plywood in Canada, while British Columbia produces primarily softwoods.[3]

Industries producing wood products include: sawmills, planing mills, and shingle mills; veneer, plywood, and oriented strand board; sash, door, and other millwork industries; wooden box and pallet industry; coffin and casket construction; and miscellaneous wood products such as toys, carvings, baskets, and crafts.[5,21] Wood is also used in the pulp and paper industry and for firewood.[5]

Occupational Exposures Overview

Inhalation is the most important route of exposure, however dermal contact may also lead to skin-related health outcomes, such as dermatitis.[2,5]

CAREX Canada estimates that approximately 340,000 Canadians are exposed to wood dust in their workplaces. The largest industrial groups exposed include: construction; sawmill and wood preservation; and furniture, cabinet, and other wood product manufacturing. The largest occupational group exposed to wood dust are carpenters. Other important occupations likely exposed are cabinetmakers, labourers in wood, pulp, and paper industries, furniture finishers, and chainsaw operators.

Potential for exposure to wood dust can also occur in window and door manufacturing, joinery shops, wooden boat manufacture, installation and refinishing of wood floors, pattern and model making, and logging.[1]

Wood dust exposures have decreased significantly over the past few decades. Furniture and cabinetry shops are generally thought to have the highest exposures, particularly during sanding and finishing work, when the finest particles are generated.[1,22] Higher exposures have been measured in plywood and particleboard mills, where wood is sawn and sanded, and near chippers, saws, and planers in sawmills and planer mills.[1]

A study in a British Columbia lumber mill also found high exposures during tasks such as sawdust clean-up, planing kiln-dried lumber, and driving mobile equipment in the yard.[23]

For more information, see the occupational exposure estimate for wood dust.

Sources

1. International Agency for Research on Cancer (IARC). Monograph summary, Volume 62 (1995) (PDF)
2. National Toxicology Program. 14th Report on Carcinogens for Wood Dust (2016) (PDF)
3. The Canadian Encyclopedia. Lumber and Wood Industries
4. International Agency for Research on Cancer (IARC). Monograph summary, Volume 100 Part C (2009) (PDF)
10. Government of Newfoundland and Labrador. Regulation 5,12 Occupational Health and Safety Regulations (2012)
11. Government of the Northwest Territories. Occupational Health and Safety Regulations, R-039-2015 (2016) (PDF)
13. The Canadian Legal Information Institute (CanLII). Government of Nunavut’s Occupational Health and Safety Regulations, Nu Reg 003-2016 (2010)
16. Government of Prince Edward Island. Occupational Health and Safety Act Regulations Chapter 0-1 (2013) (PDF)
18. Government of Saskatchewan. The Occupational Health and Safety Regulations, 1996 (2016) (PDF)
19. The Canadian Legal Information Institute (CanLII). Yukon’s Occupational Health Regulations, O.I.C. 1986/164 (2012) (PDF)
20. Occupational Safety and Health Administration (OSHA). Annotated PELs (2018)
22. Canadian Centre for Occupational Health and Safety (CCOHS). Health and Safety Report, Volume 2, Issue 10: Wood Dust More Harmful Than Once Believed’ (2004)
23. Teschke K, Demers PA, Davies HW, Kennedy SM, Marion SA and Leung V. “Determinants of Exposure to Inhalable Particulate, Wood Dust, Resin Acids, and Monoterpenes in a Lumber Mill Environment.” Ann Occup Hyg 1999;43(4):247-255.

Other Resources

  1. Occupational Safety and Health Administration (OSHA). Safety and Health Topics: Wood Dust
  2. Kauppinen T, Teschke K, Astrakianakis G, Boffetta P, Colin D, Keefe A, Korhonen K, Liukkonen T, Nicol AM, Pannett B, Westberg H. “Assessment of exposure in an international study on cancer risks among pulp, paper, and paper product workers.”Am Ind Hyg Assoc J 2002;63:(3):254-261.
  3. Demers PA, K Teschke K, Kennedy SM. “What to do about softwood? A review of respiratory effects and recommendations regarding exposure limits.” Am J Ind Med 1997;31(4):385-398.

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