The dust and sap from various types of wood can be toxic and cause a variety of health concerns including respiratory issues and eye and skin irritation.
Skin irritation can be caused by contact with the wood, its dust, its bark or its sap and result in a rash or ‘irritant dermatitis’.
Eye irritation includes soreness, watering and conjunctivitis, which is inflammation of the conjunctiva, the delicate mucous membrane that lines the inner surface of the eyelids and covers the front part of the white of the eye.
Respiratory issues include runny nose, violent sneezing, blocked nose, nose bleeds, forced asthma attacks and, although rare, nasal cancer.
Symptoms usually subside when contact with the irritant is removed. However, a serious concern is when instead of just becoming irritated the body becomes sensitized. Once sensitized, the body sets up an allergic reaction, and the body may react severely if subsequently exposed to very small amounts of the wood dust. Unlike irritation, where one can continue to work with the dust once it is controlled below the level of irritation, people who become sensitized will not normally be able to continue working with the dust, no matter how low the exposure. Some wood dusts can cause asthma as an allergic reaction.
Here is a chart showing a list of some woods and their known issues. This chart first appeared in American Woodturner magazine in June of 1990 and has become a standard reference for woodworkers. Obviously, because of the vast array of tree types this list is not complete, it is unlikely that any list could. However, it still makes a great guide to wood toxicity. The key to the lettering code used is located at the bottom of the list.
| Wood | Reaction | Site | Potency | Source | Incidence |
|---|---|---|---|---|---|
| Bald Cypress | S | R | + | D | R |
| Balsam Fir | S | E, S | + | LB | C |
| Beech | S, C | E, S, R | ++ | LB, D | C |
| Birch | S | R | ++ | W, D | C |
| Black Locust | I, N | E, S | +++ | LB | C |
| Blackwood | S | E, S | ++ | W, D | C |
| Boxwood | S | E, S | ++ | W, D | C |
| Cashew | S | E,S | + | W,D | R |
| Cocobolo | I,S | E,S,R | +++ | W,D | C |
| Dahoma | I | E,S | ++ | W,D | C |
| Ebony | I,S | E,S | ++ | W,D | C |
| Elm | I | E,S | + | D | R |
| Goncalo Alves | S | E,S | ++ | W,D | R |
| Greenheart | S | E,S | +++ | W,D | C |
| Hemlock | C | R | ? | D | U |
| Iroko | I,S,P | E,S,R | +++ | W,D | C |
| Mahogany | S,P | S,R | + | D | U |
| Mansonia | I,S | E,S | +++ | W,D | C |
| Mansonia | N | + | D | ||
| Maple (Spalted) | S,P | R | +++ | D | C |
| Mimosa | N | ? | LB | U | |
| Myrtle | S | R | ++ | LB,D | C |
| Oak | S | E,S | ++ | LB,D | R |
| Oak | C | ? | D | U | |
| Obeche | I,S | E,S,R | +++ | W,D | C |
| Oleander | DT | N,C | ++++ | D,W,LB | C |
| Olivewood | I,S | E,S,R | +++ | W,D | C |
| Opepe | S | R | + | D | R |
| Padauk | S | E,S,R | + | W,D | R |
| Pau Ferro | S | E,S | + | W,D | R |
| Peroba Rosa | I | R,N | ++ | W,D | U |
| Purpleheart | N | ++ | W,D | C | |
| Quebracho | I | R,N | ++ | LB,D | C |
| Quebracho | C | ? | D | U | |
| Redwood | S,P | E,S,R | ++ | D | R |
| Redwood | C | ? | D | U | |
| Rosewoods | I,S | E,S,R | ++++ | W,D | U |
| Satinwood | I | E,S,R | +++ | W,D | C |
| Sassafras | S | R | + | D | C |
| Sassafras | DT | N | + | D,W,LB | R |
| Sassafras | C | ? | D | U | |
| Sequoia | I | R | + | D | R |
| Snakewood | I | R | ++ | W,D | R |
| Spruce | S | R | + | W,D | R |
| Walnut, Black | S | E,S | ++ | W,D | C |
| Wenge | S | E,S,R | + | W,D | C |
| Willow | S | R,N | + | D,W,LB | U |
| West. Red Cedar | S | R | +++ | D,LB | C |
| Teak | S, P | E,S,R | ++ | D | C |
| Yew | I | E,S | ++ | D | C |
| Yew | DT | N,C | ++++ | W,D | C |
| Zebrawood | S | E,S | ++ | W,D |
| Reaction: | Site: | Source: | Incidence: |
|---|---|---|---|
| I – irritant | S – skin | D – dust | R – rare |
| S – sensitizer | E – eyes | LB – leaves,bark | C – common |
| C – nasopharyngeal cancer | R – respiratory | W – wood | U – uncommon |
| P – pheumonitis, alveolitis | C – cardiac | ||
| DT – direct toxin | |||
| N – nausea, malaise |
|
Reference: 1. Woods Toxic to Man, author unknown 2. Woods, B., Calnan, C.D., “Toxic Woods.” Br. Journal of Dermatology 1976 3. ILO Encyclopedia of Occupational Health and Safety 1983 4. Lame, K., McAnn, M., AMA Handbook of Poisonous and Injurious Plants, AMA 1985 5. Poisondex, Micromedix Inc. 1990 |
One type of wood not mentioned in this list is the spalted varieties. Spalting is a by product of the natural rotting process created by mold and decay. Although it creates a beautiful figured wood the dust created when sawing, sanding or turning is highly toxic and has a reputation for causing respiratory problems. More specifically, the fungi that causes spalting is what triggers the asthma like reactions that can be severe.
Although working with wood can be hazardous you can minimize your risk by minimizing your exposure. This can be achieved by being more aware of which woods offers potential problems, substituting some woods for others, utilizing proper dust collection and filtering systems, using proper respiratory protective equipment, wearing protective clothing and thoroughly washing after exposure.
The intent of this article is not to raise fear in working with wood but to raise awareness of some of the health issues associated with working with wood. Because of this please do not avoid working with wood, embrace it, but when you do just make sure that you are taking protective measures. Remember, wood toxicity is nothing to sneeze at!
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