As much as I like putting a nice finish on a wood project, that first whiff of fumes from the can kind of spoils the experience for me. I suppose it’s because I don’t like getting bombarded with a witches brew of chemicals – chemicals with names I can’t pronounce, and names that I’ll probably never learn the full meaning of.
One thing I have learned, though, is that it’s nearly impossible to finish a piece of wood without releasing some amount of toxins in the air. Whether we like it or not, the chemical properties of a finish — the solvents, pigments, and binders — are what make a finish what it is. The trick then, is to choose a finish with the least amount of offensive chemicals in the mix, but still effective in creating a durable, long-lasting surface.
Look for the VOC Rating
Federal law requires that manufacturers include a VOC (volatile organic compounds) rating on the label. The rating is important because VOCs can pose certain hazards to the environment and to the person using the product. The rating is displayed in grams per liter (g/l), and tells us the relative concentration of VOCs that are present in the mix. As a general rule, the lower the VOC rating, the lower the potential hazard this product might pose. However, there’s a little more to the story than that.
Is a Low VOC Rating Enough?
I think we can all be happy that manufacturers are developing new finishes with lower VOC ratings. That’s the good news. The bad news is that consumers are often lead to believe that VOC ratings represent a complete picture of the potential hazards lurking in the can.
Unfortunately, this isn’t always true. Sometimes understanding the true toxicity of a product goes beyond what a simple VOC rating can tell us. For example, the way you go about using a finish can be just as important as the VOC rating itself (see Your First Line of Defense below).
Another problem with VOC ratings is that the highly-publicized number can be easy fodder for greedy marketers wanting to target environmentally-conscious buyers. In fact, some manufacturers have ended up in court over exaggerated claims of “low” or “zero” VOC content in their products. Hopefully other manufacturers are heeding the warning and making certain their VOC ratings are accurate.
Is a High VOC Rating Always Bad?
Sometimes a high VOC rating can make a wood finish appear more hazardous than it really is. For example, shellac-based finishes (shellac is approved by the FDA for use in food—like candy and vitamins), have a relatively high VOC rating. Why? The solvent used in shellac is denatured alcohol – a fairly potent organic compound in the family of VOCs. However, the potential hazards in shellac-based finishes are relatively short lived. That’s because denatured alcohol causes shellac to dry at a very fast rate, which reduces our overall exposure (some finishes can continue to emit toxic fumes for years).
Some VOCs are Definitely Bad
When shopping for a finish, I like to use the VOC rating as a “general” measure of toxicity levels across different brands. However, as I mentioned earlier, VOC ratings are not a foolproof indicator of a product’s toxicity. That’s why I also examine labels using the following checklist, just to make sure I’m avoiding chemicals with the worst reputations.
The Worst of the Worst VOCs
1. Benzene (benzol)
3. Xylene (xylol)
4. Carbon Tetrachloride
5. Methylene Chloride
6. Methyl Chloroform
7. Ethylene Glycol
Your First Line of Defense
Sometimes the best way to avoid the hazards associated with finishing wood is to simply be smarter about how you use the product.
1. Buy Only What You Need
Keeping unused paint and finish in the shop is bad for both you and the environment. Even with our best attempts to keep a tight lid on the container, unused finishes usually end up emitting VOCs into the home indefinitely. And while some of us know better than to toss a near-empty container of finish into the trash—many don’t realize (or care) that whatever chemicals we put in the garbage can ultimately find there way into our groundwater. If you have leftovers, check with your local waste management office to find out about special pick-up days or drop-off points for getting rid of unused paint and finishes.
2. Work Outdoors
The best place to apply a finish is outside of the house—in a driveway, the backyard, or a detached garage with the door open. I realize this isn’t always practical. So if you must work indoors, take a few extra precautions, like opening windows, running fans, and wearing a mask. If you’re pregnant, have allergies, or are extra sensitive to chemicals, stay out of the area for at least 48 hours.
3. Choose Finishes that Last
The more often you have to refinish your wood project, the more often you expose yourself and the environment to whatever toxic chemicals are in the can. In some cases, this means a more durable finish (with higher VOC ratings) might be a more eco-friendly choice, if it provides a longer lasting surface that does not need to be periodically refinished. This is especially true with surfaces that are subjected to harsh conditions — like floors, tables, and outdoor projects.
Food for Thought: Indoor Plants Reduce VOCs in the House?
An interesting study by the University of Georgia found that certain indoor plants have the ability to remove harmful VOCs from indoor air (a process called phytoremediation). The study tested twenty eight different species of indoor plants, with five plants rated as “superior” in their ability to remove VOCs.
1. Purple Waffle Plant
2. English Ivy
3. Variegated Wax Plant
4. Asparagus Fern
5. Purple Heart Plant