Ask the Expert Question-and-Answer Archive

by Ron Joseph

April, 2001

Toxic Filters in Spray Booths

Q. What levels of toxic chemicals in our spray booth filters do we have to reach before we must have a certified toxic substance removal company dispose of the used filters?

A. There is no regulated level of toxicity at which filters must be disposed of as hazardous waste. In fact, do you know if your spray booth filters have "toxic" ingredients on them? Chromates and other heavy metals are considered toxic, but most other paint ingredients are not considered toxic.

IF your filters contain chemicals that are considered to be toxic, then you must dispose of them as hazardous waste and have a specializing company remove them.

Generally, the vendor of your filters will tell you at what pressure differential you should replace the filters. To measure the pressure differential you should have a calibrated manometer on the wall of your spray booth. When the filters are new and clean the manometer should be calibrated to zero. Then as the overspray builds up the pressure differential will increase. Usually, it is good practice to change the filters when the differential gets to about 1 - 2" Water column (W.C.), but as I suggested, this recommendation should come from your filter vendor.

Hope this helps.