Ask the Expert Question-and-Answer Archive

by Ron Joseph

March, 2006

Health and Safety with Intumescent Paint

Q. We are purchasing a condo loft in St. Paul, MN, whereby the seller is developing a historical building (circa 1900) into condos. The building has iron columns that become part of the various walls separating the condos. The seller indicates that fire codes now require that the iron columns be painted with intumescent white paint that will be then covered with a black paint.

We're questioning the St. Paul building officials to determine if this painting process is, in fact required.

We worry about health issues as the columns will be part of our walls in the kitchen, living/dining room, bathroom and bedroom. Is Intumescent paint safe for us? My wife and I are both age 68.

A. Once the coating has been applied, dried and cured there is minimal risk to you. In any case, I'm not aware that intumescent paints posed a health risk, but even if there are ingredients that are toxic, they encapsulated in the paint resins. If you apply yet another coating of paint over it; in this case black non-intumescent paint, you further reduce any risk.

If the condo experiences a fire and the intumescent paint performs as it should, by expanding and forming a char to protect the substrate, then you would need to speak to a toxicologist before reentering your home. I have no idea what chemicals would be emitted during the fire, but you can face that hurdle if and when it should ever occur.

I cannot tell you that there is no risk. For instance, if either you or your wife suffer from allergies to certain chemicals, you could be sensitive to the paint. But for the most part I do not consider that you will be exposing yourself to a significant (if any) health risk.

Best wishes,

Ron Joseph