Is Water-based Catalyzed??Polyurethane??Toxic?


Hello, I am a craftsman who installs floors, and have used water base catalyzed polyurithane, because I considered it less toxic, and have thought it to be easy to use. I see you list as a con of WBP, that it is toxic, could you tell me more on this?

Thank you,



Dear Ben

While certainly you are exposed to less fumes as you coat the floor, some of solvents in this finish can cause dizziness. Read the Dura Seal article in the Floored News section for more about these mildly toxic solvents called glycol ethers.

But the real fly in the ointment is the azridine catalyst or hardener, that is supplied with the commercial water based finishes like Street Shoe and Traffic. I attended a seminar at a fancy hotel given by Basic Coatings here in Toronto about 15 years ago. They were demonstrating the Street Shoe product, and I saw the factory rep don rubber gloves up to his elbow, before he snow plowed the finish. At the time I found it quite alarming, and the few times I needed to use this finish, I also used rubber gloves. But I didn’t know why.

I had thought the little bottle of azridine was poisonous by not too deadly. Well now I know better. This stuff is a confirmed carcinogen, and when absorbed through the skin ( it easily does) causes tumors, and prolonged exposure to this seems to cause skin reactions, and allergies. You should never pick up a bottle of this stuff with your bare hand. And be careful not to splash it on yourself or your clothes.

I only will use it (street shoe) as a substitute for MC poly, and only for commercial jobs. As I do almost all residential jobs now, I have thankfully not had to use this stuff for years. The MC poly was deadly to my lungs and I almost died after getting a lung-full of the xylene and toluene fumes years ago. But If I were you I would switch to the safer oxygen cross linking variety of water based finishes, as described in the Dura Seal article. Oh, and the other water based finish catalyst called Carbodiimide is fairly safe, but makes a much weaker finish ( as in the flecto renewal system). But if you want to avoid handling the azridine, you should try the Dura Seal 2000 water based finish system. It has the hardener in the cap, and you puncture this seal on the cap and let it flow down into the gallon without touching it. The Dura Seal rep in Texas told me that once the azridine is in the finish it is harmless. I’ve heard nothing to confirm this other than from Dura Seal. So I will still wear rubber gloves to apply and clean my applicators. This method doesn’t allow you to use a partial gallon of course. I don’t think it’s selling that well just for that reason.

I should mention that I suffer (not too badly) now from Hairy Cell Leukemia, which is a rare, and rarely fatal blood disease. And I can’t help but think back on all the chemicals I’ve handled over the last 24 years, and wonder why me I’m just in the middle of writing a health and safety article for this web site, and I wonder if anyone will bother to read it.

As always your Most humble servant, Joseph, the Wood Floor Doctor.