Is that wood toxic?

When working with a power carver (think, Dremel), you have to be very careful about protecting yourself from the effects of wood dust. Dust collection is a big deal to power carvers. And even when hand-sanding a small carving, one has to be careful. The effects of inhaling wood dust are uncomfortable at best and at worst, deadly.

This is especially true when carving “found wood.” If you’re working with basswood, the effects of inhaling a few dust particles will be a slight cough and maybe a sore throat for a few days. You probably don’t want to inhale a lot of it, though. But unless you inhaled enough basswood dust to physically block your lungs, you wouldn’t die from it.

Not all woods are as benign as basswood.

Large pieces (3 inches or more thick) of poison ivy, for example, have beautiful grain. But you don’t see people carving the stuff because most people are highly allergic to it. Other woods that cause allergic reactions on contact include (among many others) poison oak, poison sumac, walnut, and fig. Most people are allergic to the poison oak, ivy, and sumac. Allergies to walnut and fig are not uncommon, but usually not as severe. In any case, serious health problems due to contact allergies are rare.

That’s not so with dust. The dust from many different types of wood can cause severe respiratory problems. Pages such as this Toxic Wood Chart list dozens of species whose dust can be the cause of everything from mild skin irritation to severe respiratory distress. Wood dust can be deadly toxic.

A common ornamental tree here in Texas is called “mimosa.” It’s a medium-sized tree, fast growing, with beautiful flowers that have a very pleasant odor. The trees typically live 20 to 30 years. There’s been a lot of development in my area in the last 30 years, and I’m seeing more dead mimosa trees. The heartwood is beautiful. I want to carve the stuff, but somebody told me, “mimosa is deadly toxic.” I don’t take much on faith these days, so I thought I’d do some research to see if it really is toxic.

There are many dozens of plants that are commonly called “mimosa.” So far as I can tell, the only thing those plants have in common is that they are members of the family Fabaceae, or the legume family. The sub-family Mimosoideae contains many of the plants called “mimosa.” But the tree we commonly call mimosa around here is probably Albizia julibrissin, which is not very closely related to Mimoseae. To further confuse matters, several species of Acacia are also referred to as “mimosa.” Those, too, have some nice looking wood that I’m sure people carve.

I can undoubtedly discover the exact type of tree we’re calling “mimosa” around here, but I don’t know how to determine whether or not it’s toxic. I suppose I could try working it without wearing any kind of mask or filter, but that seems like a high-risk endeavor. I’d rather somebody could tell me one way or the other.

Mind you, I typically wear a simple mask when sanding or working with the power carver, but if this stuff is as toxic as the charts say then I’ll want to wear something a bit more protective and that includes a full face mask. I don’t have any qualms about carving the stuff, but if I’m going to raise dust then I need to be a lot more careful.

There’s a disconnect between botanists and wood carvers. Botanical sites tell me lots of things about the trees, including what parts of the tree are toxic when ingested. But botanical sites don’t tell me if the dust is toxic. And wood carving sites will tell me that “mimosa” is toxic, but they don’t tell me which type of mimosa they’re referring to!

This isn’t uncommon, by the way. There are over 600 different species referred to as “oak,” and “willow” covers around 400 species. “Cypress” encompasses dozens of different species, most in the same genus but not all. And don’t even get me started on ironwood, which can mean any one of a couple dozen species.

In any case, I’d sure like it if botanical sites included information on dust toxicity, and if wood carving sites were more specific in identifying their woods.

I should mention here that if you’re working with a wood that you can’t identify, or if you can identify the type of wood but don’t know where it came from, you should be cautious. Pallets, for example, often contain useful wood. The wood might be easily identified, but pallets are often treated with some rather nasty chemicals that, if inhaled, can cause some serious problems. Old doors or tables that were finished with some type of stain or varnish can also be dangerous. The same thing goes with fungi that cause spalting in maple and in other woods. Some of those fungi, if inhaled, will want to set up shop in the warm, dark, moist environment in your lungs. Fungus can be a problem even in kiln-dried wood such as the ambrosia maple that I love working with.

When in doubt, wear a protective mask.