Toxic timbers

Information provided by Dick Veitch and Sergio Battistessa.

There are various forms of toxicity caused by exposure to woods through dusts or by direct contact. As a general rule: dust from every wood is toxic if you inhale enough of it.

You can develop allergies following contact by touch (sap, shavings, or dust on your skin) or through the inhalation of dust. In other words, both large and small particles can sensitise you to the allergen. The reaction can be a skin or lung reaction. Skin reactions are generally itchy rashes, often worse when sap is present in the chips. Lung reactions are generally chronic coughs or wheezing, but may be merely annoying nasal irritations.

Other types of problems come from chronic exposure to dusts that are small enough to reach the small airways and alveoli (the tiny sacs deep in the lung tissue were oxygen in the air gets transferred to the blood). Dusts larger than 10 microns settle out in the upper airways (nasal cavities and back of the throat). Less than 0.1 micron particles are so small that they don’t settle anywhere very much. They go in and out. Between 0.1 and 10 microns they reach the small airways (branching of the main windpipes into the lung tissue) and some of them stay.

The risk isn’t just cancer, but also scarring, inflammation, and other damage, that eventually causes stiffening of the lungs so that the work of breathing increases. It’s not quite the same as your typical smokers’ emphysema, but it’s similar enough, and less responsive to treatment (eg. antiinflamatories and the inhalers that can be used to open constricted airways).

Of course, woodworkers and boat builders can develop problems due to exposure to other materials such as epoxies and silicates. Glass, being basically silica, and of course colloidal silica, both could cause silicosis. Epoxies, particularly the hardeners, are well known as allergy sensitisers, and can cause long term chemical damage to the lungs if inhaled in sufficient amounts.

In books, medical journals, and on websites, more than 100 tree species are listed as having some toxic effect on persons who use the wood. Unfortunately many lists use common names which may refer to many different species, eg “blackwood” which is a common name for vastly differing genera on most continents.

This toxicity of wood dusts should not be confused with toxicity of fruit, seeds, and leaves as some toxic woods come from trees with edible fruits and some trees with toxic fruit have wood which is not known to be toxic.

The list below brings together information from published and proven records on woods which New Zealand woodturners may work. As we gather a large variety of woods from garden-grown trees, this list can not be a complete reference. Some references which woodturners can use to check on other timbers are given after the table.

Name of the treeReported effects
Alpine Ash, or Messmate, or Tasmanian Oak (Eucalyptus delegatensis, or E. obliqua, or E. regnans).Irritation to nose, eyes and throat, dermatitis 1,3,5
Apple (Malus spp)Nothing reported
Beech, European(Fagus sylvatica)Nasal cancer.1,3,4,5 Dermatitis. 1,3,5 Decrease in lung function.2,3,5 Eye irritation. 3,5 Sensitiser. 4
Beech, NZ (Nothofagus spp)5 speciesIrritation to mucous membranes. 7
Black maire (Nestegis cunninghamii).Nothing reported
Black walnut (Juglans nigra).Sensitiser of skin and eyes.4,5
Blackwood (Acacia melanoxylon).Dermatitis, asthma, irritation to nose and throat.1,3,5 Sensitiser of eyes and skin. 3
Brush box (Tristania conferta)Nothing reported
Camellia ( Camellia japonica)Nothing reported
Camphorwood (Cinnamomum camphora)Nothing reported
Cherry (Prunusspp).Nothing reported
Chestnut(Castanea sativaDermatitis (possibly from bark lichens). 2,3,5
Ebony. (Ebeaceaespp)Skin inflammation.1,2,3,4 Acute dermatitis, sneezing.1,2,3 Conjunctivitis.1,2 Possibly a skin sensitiser.3
English elm(Ulmus procera).Dermatitis, irritation of mucous membranes, cancer.1,3,4,5
European ash (Fraxinus excelsior).Decrease in lung function.2,3,5 Rhinitis, asthma.5
European box (Buxus sempervirens).Sensitiser, dermatitis, irritant to eyes, skin, nose and throat.3,5
European walnut (Juglans regia).
Dermatitis, nasal cancer.1,5 Sneezing, rhinitis.2,3 Sensitiser.3
GrapefruitNothing reported
Gum (Eucalyptusspp.).Nothing reported for most species
Holly (Ilexspp).Nothing reported
Jarrah (Eucalyptus marginata). Irritation to nose, throat and eyes.1,3,5
Kahikatea (Dacrycarpus dacrydioides).Dermatitis, irritation to nose, throat.1,7
Kamahi (Weinmannia racemosa).Nothing reported
Kanuka (Kunzea ericoides).Nothing reported
Kauri (Agathis australis).Non-specific respiratory symptoms reported. 6
Kowhai (Sophora tetraptera or S. microphylla)May be toxic if chewed. Light to severe coughing and sneezing. (Sid Ware pers. comm.)
Laburnum (Laburnum anagyroides).Seeds highly toxic.5 Wood may be toxic if chewed.
Lacebark (Hoheria populnea).
Nothing reported
Lancewood (Pseudopanax crassifolium).Nothing reported
Lawson cypress (Chamaecyparis lawsoniana)Nothing reported
Lawsoniana (Chamaecyparis lawsoniana)Nothing reported
Macrocarpa (Cupressus macrocarpa).Nothing reported
Magnolia (Magnoliaspp.).Nothing reported
Mahogany (Swietenia mahogani)Dermatitis, mucous membrane irritation.2,3 Respiratory disorders.2,3,4 Sensitiser.4 Giddiness, vomiting, furunculosis.5
Matai (Prumnopitys taxifolia).Nothing reported
Miro (Podocarpus ferrugineus).Nothing reported
Mountain ash (Eucalyptus regnans)Dermatitis, irritant to nose, eyes and throat.3
Ngaio (Myoporum laetum) May be toxic if chewed.
Norfolk Island pine (Araucaria heterophylla). Nothing reported
Oak, European (Quercus roburand Q. petraea).. Asthma, sneezing, eye irritation.2,3 Dermatitis.5 Sensitiser.3,4 Nasal cancer.4,5
Olive (Olea europaea)..Irritant and sensitiser of eyes, skin and lungs.3,5
Pear (Pyrus communis). Nothing reported
Pine (Pinus radiata). Contact allergen.7
Plane (Platanusspp).Nothing reported
Plum (Prunusspp.).Nothing reported
Pohutukawa (Metrosideros excelsa).One report of headaches and nasal irritation lasting several days. (John Humphris pers. comm.)
Puriri (Vitex lucens).Nothing reported
Rata(Metrosideros robusta and M. umbellata).Nothing reported
Rewarewa (Knightia excelsa).Nothing reported
Rimu (Dacrydium cupressinum)Irritation to nose, eyes, cough.1,3,5
Robinia, black locust, false acacia (Robinia pseudoacacia). Irritant to eyes and skin, nausea, malaise.2,5
Sheoak (Casuarinaspp.).Nothing reported
Silky oak (Grevillia robusta).Sap may cause blistering of skin, inflammation of eyelids.1 Green timber and dust may cause dermatitis.1
Silver birch (Betula pendula).Dermatitis and respiratory health problems.5
Sycamore (Acer pseudoplatanus). Nothing reported
Taraire (Beilschmiedia taraire). Nothing reported
Tawa (Beilschmiedia tawa).Respiratory symptoms reported.6
Teak (Tectona grandis). Dermatitis.1,2,3,5 Conjunctivitis, over sensitivity to light, swelling of scrotum, irritation to throat and nose, nausea.1,3,5 Nettle rash.2 Respiratory disorders.2,3,4 Sensitiser.4
Titoki (Alectryon excelsus). Nothing reported
Totara (Podocarpus totara). Nothing reported
Wattle (Acaciapp.).Nothing reported
Yew (Taxus baccata).Congestion of lungs, nausea, fainting, irritation of alimentary tract, visual disturbances.1 Dermatitis, headache.1,2,3 Blood pressure drop, cardiac effects.2,3 Direct toxin.4>


  2. HSE information sheet from the British HSE Information Service
  3. Terry Porter, Turning toxic timber. Woodturning No 87
  4. American Woodturner, June 1990
  5. Mark Baker, Wood for woodturners. GMC Publications 2004
  6. Alan E Norrish, Richard Beasley, Errol J Hodgkinson, & Neil Pearce, NZ Medical Journal 105:934, 1992
  7. Wade Cornell, Toxic properties of wood. N Z Tree Grower, 2003