What is published below was in Kansas City Woodturner's newsletter "Wood Chips" - September 2005

Toxicity of Wood

The is no doubt that some woods can be potentially toxic to some people. The question is always one of “what degree”. This cannot truly be answered. Each individual has different degrees of resistance, some more prone to allergic reactions, and others not so. Every day our knowledge of tree biology and chemistry grows, leaving with more information, but also more questions. How this relates to each individual is impossible to know. All we can say is “be cautious”. Use new woods in a limited way, with proper respirators, until you know that it has no adverse reaction with your body.

Be cautious - just because something doesn’t cause a reaction the first time doesn’t mean you’ll never have an allergic reaction. Your sensitivities can build with exposure. Allergy-prone people should be more cautious in the woods they choose and everyone whould limit exposure to sawdust of new woods the first few times you work with it.
Have fun, but be healthy!

For centuries, it’s been fairly common knowledge that some woods could hinder your health. As far back as 60 A.D., the Roman historian and naturalist Pliny the Elder described a case where four soldiers actually died after drinking wine from hip flasks made of yew. Of lesser gravity was the experience of a few German sawyers in the early 1700s. It seems they developed chronic irritation of the nose and eyes, as well as headaches, from sawing bald cypress.

What are your chances of a reaction to wood? Statistics say that only 2 to 5% of all people develop an allergic sensitivity to one or more compounds found in wood. But, if you handle a lot of potentially toxic species, and work with them long enough, you increase your chances of an allergic reaction.

Any dust, including wood dust, mildly irritates the sensitive mucous membranes of your nose and eyes, making you sneeze and tear. The dust of some woods such as western red cedar and rosewood can be especially bothersome. However, other woods, called irritants, can make you even more uncomfortable, with a rash that classifies either irritant dermatitis or allergic dermatitis. The rash usually has a uniformly red, swollen area that may erupt in blisters, and typically first shows up on the webs of skin between your fingers. Irritant woods include black locust, cocobolo, ebony, oleander, satinwood, sequoia, and yew.

However, for you to get an allergic-type rash, you first must be allergy-prone to one or more of the chemicals found in certain woods called sensitizers. And, it may take repeated contact for your body to develop a great enough allergy for it to react (the so-called “latency period” of as little as five days and up to 6-8 months). If you do eventually get a reaction, the rash will look like poison ivy - red with small, individual, itchy bumps. Sensitizer woods include cypress, balsam fir, beech, birch, elm, greenheart, mahogany, maple, myrtle, redwood, sassafras, spruce, walnut, willow, western red cedar, and teak.

In addition to the actual wood dust, molds frequently trigger reactions also. One that actually grows in woods happens to be extremely potent: Cryptostroma corticale. This mold lives happily between the bark and sapwood of many hardwood trees, especially favoring maple and birch. It’s responsible for the marbleized spalting that woiodturners prize, and for “maple bark stripper’s disease,” a condition with all the symptoms of a sever respiratory allergy.

If you have an aspirin allergy, be wary of willow and birch. Both of these species possess significant concentrations of salicylic acid (the predecessor of aspirin) and very sensitive individuals might only need casual exposure, such as a whiff of sawdust, to react.

Never say “no” to a dust mask. Among woodworkers, the chances of developing nasal and sinus cancer run about 5-40 times greater than non-woodworkers. Although researchers haven’t identified the exact cancer-causing compound (primarily because the disease has a latency period from 30 to 50 years), some evidence points to dust from wood with high tannin content, such as chestnut, oak, redwood, western red cedar, and hemlock.

If you are sensitive to wood dust, work in a well ventilated area (this also reduces the risk to mold), avoid unseasoned woods as much as possible, and wash or shower frequently. If you develop persistent rashes or respiratory problems, contact your physician or dermatologist.

Click on this link for a list of woods toxic to man as appearing in American Woodturner, June, 1990