Use an oxalic acid vaporizer with caution
A friend and master beekeeper from Connecticut, Bill Hesbach, wrote the following account about his misadventures with an oxalic acid vaporizer and a face mask. First posted on BEE-L, the story is a cautionary tale of the hazards of working with oxalic acid, and a reminder that when things begin going south, they sometimes just keep going.
Thank you, Bill, for allowing me to re-post your story.
This accident was operator error but I wanted folks to know what occurred because I think it can happen to anyone using this device. I’ve been using a ProVap 110 successfully for two years without a problem until yesterday. I use it per the manufacturer’s instructions with one exception.
The instructions say, “This vaporizer is most easily used from the back of the hive, where a small (¼”) hole is drilled in the back center of the ¾” rim of the bottom board that supports the bottom brood box.”
The exception is that, with my equipment, I couldn’t drill the holes in the bottom board rim so I drilled them in the [brood] box below the rear hand hold. It worked just fine until a frame inside one box managed to get aligned with the hole. That only leaves about 3/8-inch between the frame and the inside surface of the box where the hole is drilled.
When I inserted the discharge tube, which is about 1½ inches long, it must have butted up against the frame’s end bar leaving no room for the gases to exit. As a result, when I turned the ProVap over to sublimate the oxalic acid, the white Teflon lid that holds the oxalic acid exploded off the device spewing extremely hot gas and liquid OA everywhere. I had a full-face respirator which saved my face from severe burns (see the photo) but I learned something else about the respirator.
Fitting a respirator
First, when you wear eyeglasses like I do, a full-face mask doesn’t fit quite right and therefore this is what’s recommended by the safety experts:
“If you wear contact lenses, you can wear a full-face mask or a half-face mask and chemical goggles. But for folks with traditional glasses, it has to be a full-face mask with the proper corrective glasses insert, since the arms of eyewear can get in the way of a proper fit on a half-face mask.”
Well, in this incident, the air around my respirator was filled with gases and just like the safety experts said, some began to infiltrate around those eyeglass arms which prompted me to drop everything and run to safety where I could remove the respirator. Since I never had an incident before I didn’t realize that the way I was wearing the face mask would allow that to happen.
I’ve since taken two corrective actions. First, I installed a spacer on the discharge tube of the ProVap so it can’t extend beyond the 3/4 thickness of the box, therefore, avoiding any frame obstructions inside when they happen to align with the hole. Second, since my eyeglass arms are just thin wire, I’m now tightening the pull straps on the mask enough so that when I inhale I can feel a slight compression of the mask which indicates I have the needed vapor lock.
Hope this helps.