Dust Collection in a Shared Shop: A Wood Scientist’s Perspective

We are all well aware that dust collection is critical to maintaining a healthy shop work environment. Hopefully we are all aware that point of generation collection is far better than relying on a fan, being outdoors, or a hanging air cleaner that hasn’t had its filter cleaned since 2012.

We know what we should do. And in our own shop, it often seems manageable (if not expensive).

It’s in group shops, larger shops, and commercial shops where issues can be overwhelming. When we are no longer responsible only for ourselves, when the space is large, when multiple people are working at once, dust mitigation and collection can go, quite quickly, into the toilet. Especially since no one wants to correct someone else’s failure to hook their sander to a vacuum.

In the eleven or so years I’ve taught woodworking and woodturning courses in the Department of Wood Science & Engineering at Oregon State University, I’ve heard just about every excuse one can think of for ignoring dust safety.

The top four include:

1. I forgot.
2. I was only doing a quick job.
3. I don’t know how to hook up XYZ.
4. Wood dust doesn’t bother me.

The argument always follows that if you care so much about the dust, you are welcome to wear a mask but they’re going to keep on going, thank you very much.

Ignoring the aforementioned (garbage) reasons, there’s a deep, willful harm in the lackadaisical response—you can wear a mask if you want—and the harm isn’t just to the person refusing to wear the mask. And to understand why, first, you have to understand wood not as a material, but as a living organism.

The Effects of Wood Extractives

Wood was alive, and most trees are far older than you will ever be. They have their own pathogens, just like humans. And just like humans, trees have an immune system. Part of that system involves a compound known as extractives, which are chemicals produced by the tree, usually, around the time the sapwood transitions to heartwood. Extractives are produced by the tree for a number of reasons, but a big one is for defense. Extractives are meant to kill things, including things in the animal kingdom. And while yes, you are much larger than a beetle, that doesn’t mean that a tree’s extractives don’t have an effect on you, too.

For the purposes of this article, let’s move forward noting:

1. Wood dust, as a general particulate, is bad for your lungs
2. Extractives in wood dust can cause specific, additional responses in humans and other animals

Types of Extractives

Because we are all on the same page (hopefully) with #1, let’s spend more time on #2. Extractives are part of wood dust, because extractives are part of the tree.

They come in three main varieties of interest to woodworkers:

1. color (think purple in purple heart, brown in walnut)
2. texture (silica in teak)
3. smell (like many cedars)

All images show the endgrain of the wood at 10x magnification.

Color and texture-based extractives tend to be bound up in the wood itself, and move out with solvents. These solvents can be as basic as the oils on your skin, a pot of boiling pasta water, or the mucous in your nasal cavity. Aromatic extractives are released when wood is cut or sanded. Let’s discuss each in detail, as it relates to wood safety, particularly in a large, shared shop.

COLOR

This is the easiest type of extractive to work around since it’s so visible. Wood at its base is a pale creamy white to beige. Any more color than that and you’re looking at extractives. Purpleheart, bloodwood, zebrawood, black walnut, cherry heartwood—these colors are all made by the tree in the natural process of turning sapwood to heartwood.

It’s important to note that not all brightly colored wood is bad. Fruit woods, like apple, cherry, and plum, often have dark heartwoods. However at the moment there is no evidence that fruitwood extractives are particularly troublesome to humans. This may be due to fruit trees needing animal dispersal of their seeds (and no animal is going to eat the fruit of a tree that has toxic wood…I assume), or any number of other reasons. The point being, if you must have a darker wood, you have options that are less harmful to your coworkers.

TEXTURE

The oily feeling of teak, the heaviness of rosewood, the dull graininess of ipe, these are all due to texture-type extractives. The one most woodworkers are familiar with is silica, which is prevalent in teak, ipe, and other species. This extractive is prized for wooden boat building, as the silica in the wood dulls the shells of marine borers and extends the life of the ship. In the woodshop, silica dulls blades, irritates and abrades skin, and scratches eyes. Along with other extractives, if left on the skin too long reactions can occur. Get some of it in your eyes from your dirty hands, and, well, you get the idea.

Every year I run a tropical woods unit with my students for two weeks. Outside of these weeks the students are not allowed to use tropical wood or heavy extractive wood anywhere in our shops. And every year, during these two weeks, I have around half the students get either eye infections so severe one eye swells shut, infected splinters, or dermal skin reactions that take over half their body.

Even in a fully grown human adult, extractives are a problem.

AROMATIC (ODOR)

No one likes this category. Scented woods are deeply loved by humans, particularly true and false cedars. Cedar extracts are in candles, soaps, and every essential oil catalog I’ve ever seen. People use cedar planks for saunas and as interior trim. The smell draws us to wood, but those smells are known as aromatic extractives. They have similar effects on the human body as the other two categories, but tend to affect people more through nasal allergies.

All images show the endgrain of the wood at 10x magnification.

A New Perspective for Shared Workspaces

With the above in mind, consider shared shop spaces. While you may not react to the extractives in ipe, you can’t guarantee that everyone who comes into the shop will not. When you don’t keep the space dust free, when you leave residues on surfaces or floating in the air, you make the shop an even more dangerous place to be. Someone coming in to grab a ruler could get purpleheart dust on their hands and develop a rash. They might wipe an eyelash from their eye and get an eye infection. Long-time workers in the shop may develop such severe sensitivities to a given species that they can’t be in the same room as that wood. Anyone can be sensitized to any wood species over time. Just talk to former mill workers, particularly those who worked in cedar shingle mills.

All of this is completely avoidable with appropriate dust collection.

Consider it another way—in terms of consent. Adults can choose to smoke cigarettes. It’s assumed the adult has weighed the pros and cons and is making an informed decision. That same adult doesn’t have the right to blow smoke at another person, especially not in secret. The other person has not consented to or been given the chance to make an informed choice.

The same is true of wood dust. What someone chooses as a calculated risk for themselves is fine, but they don’t get to make that same decision for other people—especially when most people are unaware of the risks associated with wood dust.

Now, however, you have the knowledge. The next time you’re in a larger, shared use shop, the next time you go into work, why not mention that the smell of cedar can make people sleepy, or that teak dust can cause hives, or that ingestion of extractives from some rosewood species can decrease sperm count and sperm motility? The next time someone starts a random orbital sander without a HEPA-rated vacuum attached, why not ask if you can help them attach it? Set a good example yourself by always wearing a well-fitted respirator and using point-of-use collection systems. Do it for yourself, do it for others, and do it for science.

All images show the endgrain of the wood at 10x magnification.

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Written by Seri Robinson

Seri Robinson is an associate professor of wood anatomy at Oregon State University. They are also a sculptor and woodturner. Dr. Robinson has written numerous articles about wood anatomy, wood science, and woodturning in publications like Fine Woodworking and American Woodturner. More accessible wood science information can be found in their books, particularly Living With Wood: A Guide for Toymakers, Hobbyists, Crafters, and Parents, and Spalting 101: The Ultimate Guide to Coloring Wood with Fungi.