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Solid wood is totally safe to touch and to expose to food.

But wood dust is a different matter.

Let’s discuss the situation

Wood dust is no good for your lungs or eyes, and some wood dust can also react with your body. So woodworkers need to take precautions against dust when working with any lumber, whether the wood is domestic or exotic.

Possible reactions include skin rashes, watery eyes, respiratory problems, headaches, dizziness, or nausea.

The degree and type of reaction depends on your susceptibility to certain allergies, as well as the concentration of dust and the amount of time exposed to dust.  The same reactions from person to person are not always a certainty.

In general, toxicity is in one of three categories:

• irritation
• sensitization, and
• poisoning

Irritation

Skin, respiratory tracts, and mucous membranes get irritated easily by any fine dust because dust absorbs moisture, thereby drying out the surface with which the dust is in contact.  Itchy skin and sneezing are examples of basic irritation thanks to wood dust.  The level of irritation is proportional to the exposure time to, and concentration of, wood dust.

But irritation is not necessarily benign.  Woods like walnut and rosewood emit pleasant odors with low levels of dust, which most woodworkers equate with being one of the benefits of working with woods.  However, the natural substances in these woods that cause the scents are also potentially toxic with greater dosage exposure and concentration.  Long term effects of exposure to wood dust can include developing an allergic reaction to the dust or possibly nasal cancer.

Sensitization

Substances in wood that cause an emerging (and potentially serious) allergic reaction after repeated exposure are called sensitizers.  This type of toxicity is specific to individuals and takes time to develop – some people may experience a significant reaction to a wood while others do not.  While sensitization typically takes time and repeated exposure to develop, it is possible for some individuals to have an allergic reaction to a wood upon their first contact. 

Even if you do not have any reaction to a wood (or its dust) the first few times you use it, it’s still vital that you take precautions and avoid as much exposure as possible.  It’s possible that your body will develop a reaction the more you are exposed.

Poisoning

Universally lethal chemicals are rarely found in natural wood that’s available on the commercial market.  Most poisons in plants and trees are located in the bark and/or sap – there are some exceptions for rare woods. 

Sometimes poisonous chemicals are introduced to wood products, such as with pressure treated lumber.  Hardwoods cut for cabinetry, flooring, and furniture are not pressure treated.

Some common woods demand that woodworkers be aware of their own allergies.  Those who have an allergic reaction to aspirin should avoid using woods from birch and willow trees (Betula spp. and Salix spp.) because these contain good concentrations of salicylic acid, the key ingredient in aspirin.  See A Guide to Useful Woods of the World Appendix B for more. 

Prevention

Limit your exposure to wood dust by doing the following things:

1. Use vacuum dust collection in your shop, and keep your shop ventilated with fresh air.  
2. Use protective equipment while woodworking: dust mask, goggles or a full-face respirator, and a protective barrier cream on your arms or exposed skin. 
3. Immediately after woodworking change your clothes, washthem, and take a shower.  This will prevent transferring wood dust to your house where you or your family may be repeatedly exposed to it.

What about toxicity of wood in my finished project?

Baby cribs and food utensils are popular projects, and ones that woodworkers are often curious about “safe” woods and finishes.   The short: a sealed and finished wood poses no toxic risk. 

What about the sealer or finish then?  Solvent-based finishing products (lacquer, varnish, etc) are highly toxic in their liquid state, but cured lacquer and varnish finishes are perfectly safe.   

For projects that come in contact with food, such as salad bowls and cutting boards, you really don’t want a hard shell finish (lacquer or varnish) that can chip or rub off.  Mineral oil, teak oil, and butcher block oil are all popular and safe choices for these projects.

A popular finish for baby cribs is shellac, as the FDA approves this for use in the capsules of medications.  This approval makes many woodworkers feel that shellac is more safe than other finishes.  But cured lacquer is safe, as is any cured solvent- or water-borne finish.

For more comprehensive information regarding wood toxicity, see Appendix B in A Guide to Useful Woods of the World (ISBN 1-892529-15-7)

Type	Reaction	Site	Potency	Source	Incidence
BaldCypress	Sensitizer	Respiratory	+	Dust	Rare
BalsamFir	Sensitizer	Eyes,skin	+	Leaves,bark	Common
Beech	Sensitizer,nasopharyngeal cancer	Eyes, skin,respiratory	++	Leaves,bark; dust	Common
Birch	Sensitizer	Respiratory	++	Wood,dust	Common
BlackLocust	Irritant,nausea	Eyes,skin	+++	Leaves,bark	Common
Blackwood	Sensitizer	Eyes,skin	++	Dust,wood	Common
Boxwood	Sensitizer	Eyes,skin	++	Dust,wood	Common
Cashew	Sensitizer	Eyes,skin	+	Dust,wood	Rare
Cocobolo	Irritant,sensitizer	Eyes, skin,respiratory	+++	Dust,wood	Common
Dahoma	Irritant	Eyes,skin	++	Dust,wood	Common
Ebony	Irritant,sensitizer	Eyes,skin	++	Dust,wood	Common
Elm	Irritant	Eyes,skin	+	Dust	Rare
Goncaloaves	Sensitizer	Eyes,skin	++	Dust,wood	Rare
Greenheart(Surinam)	Sensitizer	Eyes,skin	+++	Dust,wood	Common
Hemlock	Nasopharyngeal cancer	Respiratory	?	Dust	Unknown
Iroko	Irritant,sensitizer, pneumonia	Eyes, skin,respiratory	+++	Dust,wood	Common
Mahogany(Swietenia)	Sensitizer,pneumonia	Skin,respiratory	+	Dust	Unknown
Mansonia	Irritant,sensitizer, nausea	Eyes,skin	+++	Dust,wood	Common
Maple (C.Corticale mold)	Sensitizer,pneumonia	Respiratory	+++	Dust	Common
Mimosa	Nausea		?	Leaves,bark	Unknown
Myrtle	Sensitizer	Respiratory	++	Leaves,bark; dust	Common
Oak	Sensitizer,nasopharyngeal cancer	Eyes,skin	++,?	Leaves,bark; dust	Rare,unknown
Obeche	Irritant,sensitizer	Eyes, skin,respiratory	+++	Dust,wood	Common
Oleander	Directtoxin, nausea	Cardiac	++++	Dust, wood,leaves, bark	Common
Olivewood	Irritant,sensitizer	Eyes, skin,respiratory	+++	Dust,wood	Common
Opepe	Sensitizer	Respiratory	+	Dust	Rare
Padauk	Sensitizer,nausea	Eyes,skin	+	Dust,wood	Rare
Pauferro	Sensitizer	Eyes,skin	+	Dust,wood	Rare
Perobarosa	Irritant,nausea	Respiratory	++	Dust,wood	Unknown
Purpleheart	Nausea		++	Dust,wood	Common
Quebracho	Irritant,nasopharyngeal cancer, nausea	Respiratory	++,?	Dust,leaves, bark	Common,unknown
Redwood	Sensitizer,nasopharyngeal cancer, pneumonia	Skin, eyes,respiratory	++,?	Dust	Rare,unknown
Rosewoods	Irritant,sensitizer	Skin, eyes,respiratory	++++	Dust,wood	Common
Satinwood	Irritant	Skin, eyes,respiratory	+++	Dust,wood	Common
Sassafras	Sensitizer,nasopharyngeal cancer, direct toxin, nausea	Respiratory	+,?	Dust, wood,leaves, bark	Rare,unknown
Sequoia	Irritant	Respiratory	+	Dust	Rare
Snakewood	Irritant	Respiratory	++	Dust,wood	Rare
Spruce	Sensitizer	Respiratory	+	Dust,wood	Rare
Walnut,Black	Sensitizer	Skin,eyes	++	Dust	Common
Wenge	Sensitizer	Skin, eyes,respiratory	++	Dust,wood	Common
Western redcedar	Sensitizer	Respiratory	+++	Dust,leaves, bark	Common
Willow	Sensitizer,nausea	Respiratory	+	Dust, wood,leaves, bark	Unknown
Teak	Sensitizer,pneumonia	Skin, eyes,respiratory	++	Dust	Common
Yew	Irritant,direct toxin, nausea	Skin, eyes,cardiac	++,++++	Dust,wood	Common
Zebrawood	Sensitizer	Skin,eyes	++	Dust,wood	Rare

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