4. Health Hazards

	Name Cocobolo Location Central America Texture/Grain Medium/Open Specific Gravity 1.10 Hardness Very Hard Strength Very Strong T/R Stability 5.7/2.9%

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ike many other plants, trees produce antibiotic chemicals to protect themselves from the organisms that cause disease and decay. These may also have an unpleasant effect on craftsmen who come in intimate contact with the wood.

WOOD-RELATED AILMENTS
Chemicals in wood have been found to cause or contribute to:

	Nausea and headaches
	Kidney and liver malfunction
	Skin rashes and eye irritation
	Asthma, emphysema, and other respiratory problems
	Nasal cancer

This can be a problem for craftsmen, but it shouldn’t be blown out of proportion. Not everyone is affected by the potentially toxic chemicals in wood. Only 2 to 5 people out of 100 develop an unhealthy sensitivity to them, although woodworkers have an increased risk. And not many woods contain enough chemicals to be dangerous. There are just a few troublesome species, listed in the chart below.

IRRITANTS AND SENSITIZERS
There are two common ways that a wood may affect your health — as either an irritant or a sensitizer. Irritants bother most craftsmen, at least to a small degree. These effects may be mechanical rather than chemical — fine sawdust tickles your nasal passages and makes you sneeze. More often, though, it’s the chemicals in the sawdust that irritate you. The tannic acid in oak, for example, is a powerful irritant.

Sensitizers affect only those people who are allergic to them. Allergic reactions range from a runny nose and watery eyes to hives and asthma. Furthermore, repeated exposure often causes greater sensitivity, and the reaction becomes more severe.

A very few woods contain chemicals which cause systemic reactions, affecting the stomach, nerves, kidneys, even the heart. Oleander and yew, for example, contain chemicals similar to digitalis, a heart drug.

LIMITING EXPOSURE
What can you do to limit your exposure? Quite a bit.

	Wear a dust mask. The most common way you get wood chemicals into your body is by inhaling them.
	Use a dust collector when running power tools.
	Ventilate your shop and clean it frequently.
	Keep your shop cool. Heat causes you to perspire. This mixes with sawdust and releases more toxic chemicals.

Just as important, you should not expose other people. Never use potentially toxic woods to make cutting boards, bowls, or eating utensils. Also avoid them for toys, jewelry, and items that someone might put in their mouth or rub against their skin.

One more precaution: See a doctor if you have recurrent nosebleeds or persistent sinus infections when you work wood. These are causes for special concern.

I've found that the most effective and comfortable way to protect myself from sawdust (especially during dust-intensive tasks like sanding) is to wear a positive-pressure face mask. A fan blows filtered air over my face at all times. The air leaks out around the edges of the mask, preventing sawdust from entering. This is an older model with the fan, filter, and batteries in a fanny-pack. Newer units incorporate the filter and fan – sometimes even the batteries – in the helmet. There are are also effective positive-pressure "partial" masks that look very much like ordinary dust masks.*

WOOD SPECIES	REACTION	PART OF BODY	POTENCY	SOURCE	OCCURRENCE
Bald Cypress	sensitivity	respiratory	+	dust	rare
Balsam Fir	sensitivity	eyes, respiratory	+	leaves, bark	common
Beech	sensitivity, nasopharyngeal cancer	eyes, skin nose, throat	++ ?	dust, leaves, bark dust	common unknown
Birch	sensitivity	respiratory	++	dust, wood	common
Black Locust	irritation	eyes, skin	+++	leaves, bark	common
Blackwood	sensitivity	eyes, skin	++	dust, wood	common
Boxwood	sensitivity	eyes, skin	++	dust, wood	common
Cashew	sensitivity	eyes, skin	+	dust, wood	rare
Cocobolo	sensitivity, irritation	eyes, skin, respiratory	+++	dust, wood	common
Dahoma	irritation	eyes, skin	++	dust, wood	common
Ebony	sensitivity, irritation	eyes, skin	++	dust, wood	common
Elm, Red	irritation	eyes, skin	+	dust	rare
Goncalo Aves	sensitivity	eyes, skin	++	dust, wood	rare
Greenheart	sensitivity	eyes, skin	++	dust, wood	common
Blackwood (Surinam)	sensitivity	eyes, skin	+++	dust, wood	common
Hemlock	nasopharyngeal cancer	respiratory	?	dust	unknown
Iroko	sensitivity, irritation, pneumoitis alveolotis	eyes, skin, respiratory	+++	dust, wood	common
Mahogany, Honduras	sensitivity, pneumoitis alveolotis	skin, respiratory	+	dust	unknown
Mansonia	sensitivity, irritation, nausea, malaise	eyes, skin systemic	+++ +	dust, wood dust	common unknown
Maple (Spalted)	sensitivity, pneumoitis alveolotis	respiratory	+++	dust (contains mold)	common
Mimosa	nausea, malaise	systemic	?	leaves, bark	unknown
Myrtle	sensitivity	respiratory	++	dust, leaves, bark	common

Oak	sensitivity, nasopharyngeal cancer	eyes, skin nose, throat	++	dust, leaves, bark	rare
Obeche	sensitivity, irritation	eyes, skin, respiratory	?	dust, wood	common
Oleander	direct toxicity, nausea, malaise, cancer	systemic	++++	dust, wood, leaves, bark	common
Olivewood	sensitivity, irritation	eyes, skin, respiratory	+++	dust, wood	common
Opepe	sensitivity	respiratory	+	dust	rare
Padauk	sensitivity, nausea, malaise	eyes, skin systemic	+ ?	dust, wood dust, wood	rare unknown
Pau Ferro	sensitivity	eyes, skin	+	dust, wood	rare
Peroba Rosa	irritation, nausea, malaise	respiratory, systemic	++	dust, wood	unknown
Purpleheart	nausea, malaise	systemic	++	dust, wood	common
Quebrach	irritation nausea, malaise, nasopharyngeal cancer	respiratory systemic nose, throat	++ ?	dust, bark, leaves dust dust	common unknown unknown
Redwood	sensitivity, pneumoitis alveolotis, nasopharyngeal cancer	eyes, skin, respiratory nose, throat	++ ?	dust dust	rare unknown
Rosewoods	sensitivity, irritation	eyes, skin, respiratory	++++	dust, wood	common
Satinwood	irritation	eyes, skin, respiratory	+++	dust, wood	common
Sassafras	sensitivity, direct toxicity, nausea, malaise, nasopharyngeal cancer	respiratory, systemic nose, throat	+ + ?	dust dust, wood, leaves, bark dust	rare rare rare
Sequoia	irritation	respiratory	+	dust	rare
Snakewood	irritation	respiratory	++	dust, wood	rare
Spruce	sensitivity	respiratory	+	dust, wood	rare
Walnut	sensitivity	eyes, skin	++	dust, wood	common
Wenge	sensitivity	eyes, skin, respiratory	++	dust, wood	common
Willow	sensitivity, nausea, malaise	respiratory, systemic	+	dust, wood, leaves, bark	unknown
Western Red Cedar	sensitivity	respiratory	+++	dust, leaves, bark	common
Teak	sensitivity, pneumoitis alveolotis	eyes, skin, respiratory	++	dust	common
Yew	irritation direct toxicity, nausea, malaise, nasopharyngeal cancer	eyes, skin systemic nose, throat	++ ++++ ++++	dust dust, wood dust	common common common
Zebrawood	sensitivity	eyes, skin	++	dust, wood	rare
Note: The information in this chart is based on data collected by Robert Woodcock, RN, BSN, CEN

Glossary of Terms

	Irritation – The wood species acts as an irritant, causing itching, rashes, watery eyes, and other uncomfortable reactions.
	Sensitivity – The wood species acts as a sensitizer, causing people to develop allergic reactions after repeated exposure.
	Direct toxicity – Chemicals (called extractives) in the wood species are poisonous.
	Nausea, malaise – Exposure to the wood species cause flu-like symptoms.
	Systemic – Reactions are not confined to a specific body part; they affect much or most of the biologic system.
	Nasopharyngeal cancer – A cancer that affects the back of the throat where the nasal passages open into it.

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"Abundant to all the needs of man, how poor the world would be without wood."
Eric Sloane in Reverence for Wood

4. Health Hazards
(You are here.)

Wood and Woodworking Materials/Hardwoods and Softwoods/Health Hazards and Toxic Woods,
part of the Workshop Companion, essential information about wood, woodwork, and woodworking.
By Nick Engler.

Copyright © 2009 Bookworks, Inc..

4. Health Hazards (You are here.)

Wood and Woodworking Materials/Hardwoods and Softwoods/Health Hazards and Toxic Woods, part of the Workshop Companion, essential information about wood, woodwork, and woodworking. By Nick Engler.

Copyright © 2009 Bookworks, Inc..

4. Health Hazards
(You are here.)

Wood and Woodworking Materials/Hardwoods and Softwoods/Health Hazards and Toxic Woods,
part of the Workshop Companion, essential information about wood, woodwork, and woodworking.
By Nick Engler.