Formaldehyde, sawdust and cancer

Discussion on the health risks of formaldehyde in finishes and wood dust in the air. April 4, 2001

Q.
I use Sherwin-Williams Kem-Aqua conversion varnish. I'm worried about the health risk of the formaldehyde emissions. I have a respirator cartridge specifically for organic vapors and formaldehyde, but have heard that these products can out-gas formaldehyde far above acceptable limits for 24 to 48 hours after it has been applied. How do I determine whether the amount of formaldehyde in the product is a lot or a little? The MSDS says that the % by volume of formaldehyde is .3. Is 3% a lot?

Forum Responses
I don't think .3 is 3%, but more like .3% or .003. No finish company puts anything in the finish that isn't needed--formaldehyde is needed in conversion varnish to cross link. ML Campbell is low formaldehyde. I find Campbell looks great off the gun, but in a few days it pulls back more than the same wet mils of S-W conversion varnish.


The percentage of formaldehyde on the MSDS is not the "real" percentage that is released into the air. The amount of formaldehyde released is almost a hundred fold while the product is cross linking. The only accurate way to measure is to take air samples and have them tested and get the ppm of formaldehyde. Any PTSA catalyzed resin will have formaldehyde. You may see some so-called "formaldehyde free" conversion varnish soon. They are masking the formaldehyde in a "scavenger", thus the test instruments can't read it. Always use a good mask when spraying and have good airflow in the booth area.

Bob Niemeyer, forum technical advisor


OSHA may be able to measure your air quality, confidentially (no red flags to the compliance officers). We've used their consultation service several times and always solved our safety problems.

Another health note:

Wood dust is a known carcinogen. It is dangerous to breathe in. Right now there is not enough data to determine how long you have to be exposed to wood dust and in what quantities until it presents a cancer danger.

What does not take so long to develop from breathing wood dust is industrial asthma. Once you get it you have it for life. Its effects are deleterious and lasting.

Smoking increases the risks and dangers of everything exponentially.


Should I be wearing some protection whenever I'm woodworking?

You need to wear a respirator both when woodworking and finishing.

I bought a decent mask with fancy filters on either side. It didn't take that much getting used to. I've noticed immediate benefits since using it with far less nasal congestion and the elimination of brown crud.
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