What is this blue powder?

That's so interesting. I've never seen anything like it.

did you remodel the kitchen?

I would check with your local County Extension Office to check what it is. There is a possibility it is a pesticide treatment an exterminator sprayed back there that the motion of daily life is causing to release in a powdered form.

It's got to be a pest if some sort. I would start with a professional evaluation. Good luck!

Regular boric acid powder (sold under dozens of brand names such as Roach Prufe, Borid, etc.) is to be used in cracks, crevices and voids. In other words, in places where target pests hide, forage or enter a structure but not in an area where people, pets and wildlife will encounter the material. Contrary to popular belief, this type of boric acid insecticide should not be broadcast around baseboards or in cabinets - restrict the use of this product to hidden areas only.

You often see boric acid that is colored blue. This is only a boric acid insecticide dust with blue food coloring. The color of the boric acid has nothing to do with the strength or pesticide action of the material. Boric acid is also used in baits used to eliminate ants, roaches, crickets and silverfish.

It could possibly be a type of mold. I know there are some strange colors of it

Like to know the results...

Re: Powder post beetles. Pretty sure you can rule them out. We had them in a teak wood hi-fi cabinet my husband brought back from Hong Kong years ago. We never saw them, but every morning we would find tiny piles of sawdust on the floor. There were tiny pin holes in the wood above them that looked like something was inside the wood trying to come out. Took it to be fumigated and the problem was solved. I don't think they are common in the USA.

tMy daughters built new homes in a new addtition. they were all built by the same contractors, and in all the bathrooms and kitchens the floors started turning purple and green coming through the tile.

Is there a toilet behind this wall that you use blue chemicals in?

Here is another post about blue powder - turns out if was the blue insulated board being eaten by small ants. http://www.hometalk.com/diy/home-tours/q-what-is-this-mysterious-blue-powder-that-keeps-collecting-on-our-window-and-sill-414506

Thanks

it kinda looks like the blue chalk powder that carpenters use with chalk lines, but I dont know why it would still be oozing out the wall unless somebody lost their chalkline back there.

Carpenters chalk left in the wall. Took this long for a rat to eat a hole through the container and spread the powder throughout the wall.

;) Our cats aren't doing their job then, lol. But, no mice or anything.

I had a mouse for a year and he was able to put 50 lbs, yes 50 of dog food behind my kitchen drawer. Bugs came from the area and every day I vacuumed them and bleached, never seeing the dog food. A contractor friend finally removed the whole kitchen shelving to see it. It was amazing and I was sooo embarrased. Maybe pull it out to see what is lurking there.

So the PepCo guy was at my work today. I told him what was going on and he's going to stop by the house in a couple of days. He said he's never heard of anything like it.

Can you pull off the baseboard?

Blue board + vibrations = dust

Try sealing it with clear caulk...or just vacuum it up.

I can't wait to find out. Please let us know!

Ants do this to me, but mine is brown. I had the trim boards sealed in the kitchen, and the ants just moved to another room.

I think the mouse or mice are eating the corn and saving it for a rainy day in your fabric. I would try and eliminate them. That mouse will bring his siblings in

Lynn, did you end up finding out the answer to this? My husband and I have noticed the EXACT same thing underneath our dishwasher, and we have no idea what to think!

I have the same problem. Do you have laminate flooring? My laminate flooring has blue foam on the underside of each plank, and I believe the powder is coming from this.

Not sure

I have just recently seen the same. Mine is blueish green powder form. Think it might be some pesticide, cleaned the whole area out so will see if it comes back.

We just discovered the exact same issue. I think it is from the back of laminate. We swept up a quart of it from under the dishwasher.

What is it?

I had the exact same issue. It turned out to be from the previous flooring, the underside deteriorated into this.