Asked on Dec 30, 2016

What is this blue powder?

Lynn Kramer
by Lynn Kramer
So, I was wondering if anyone has a suggestion as to what this might be. We have owned this house for 3 years and did not have this problem until about 2 years ago. I have asked a cabinetry guy that I work with and he didn't have any answers. This blue powder keeps coming from our baseboards in the kitchen.
  29 answers
  • Haysha S. Haysha S. on Dec 31, 2016

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

  • Janet Pizaro Janet Pizaro on Dec 31, 2016

    did you remodel the kitchen?

    • Lynn Kramer Lynn Kramer on Dec 31, 2016

      No, we didn't do any remodeling. The previous owner may have. I thought maybe it was chalk line but it is in random places.

  • Donna Donna on Dec 31, 2016

    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.

  • Jackie Adams Jackie Adams on Dec 31, 2016

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

    • Lynn Kramer Lynn Kramer on Jan 01, 2017

      I read about powder post beetles, but I can't figure out why it would be blue since nothing in our kitchen is blue. It's so strange.

  • William William on Dec 31, 2016

    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.

    • See 1 previous
    • Laura Kackman Laura Kackman on Jan 03, 2017

      William, I always look for your responses as they are usually right on. Always thorough with explanations.

  • Nancy landers Nancy landers on Jan 01, 2017

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

  • Arleta Arleta on Jan 01, 2017

    Like to know the results...

  • Shirley Miller Shirley Miller on Jan 01, 2017

    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.

  • Bar16047401 Bar16047401 on Jan 02, 2017

    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.

  • Stacy Stacy on Jan 02, 2017

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

  • Arleta Arleta on Jan 02, 2017


  • 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.

  • Richard Tibbetts Richard Tibbetts on Jan 03, 2017

    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.

  • Lynn Kramer Lynn Kramer on Jan 03, 2017

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

  • Kaioverbeck Kaioverbeck on Jan 03, 2017

    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.

    • See 1 previous
    • Susan Kapustka Susan Kapustka on Jan 07, 2017

      I have tons of sewing fabric. I have corn that I feed to the squirrels. When I get a mouse, I end up with kernels of corn inside the layers of fabric. When I unroll fabric, I might get 20 pieces of corn sprinkle onto the floor. I don't know if it is from an old mouse, or if I have a new mouse.

  • Lynn Kramer Lynn Kramer on Jan 03, 2017

    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.

  • Kaioverbeck Kaioverbeck on Jan 03, 2017

    Can you pull off the baseboard?

  • Ag Castor Ag Castor on Jan 04, 2017

    Blue board + vibrations = dust

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

    • Lynn Kramer Lynn Kramer on Jan 04, 2017

      There is no blue board in the area. Just tan particle board. We keep vacuuming it up. Also coming from behind baseboard that's been tacked into the wall.

  • Pat pickens Pat pickens on Jan 04, 2017

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

  • Susan Kapustka Susan Kapustka on Jan 07, 2017

    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.

  • Kaioverbeck Kaioverbeck on Jan 07, 2017

    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

  • D Lakes D Lakes on Mar 08, 2018

    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!

  • Paula Paula on Jan 18, 2019

    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.

    • See 1 previous
    • Paula Paula on Jan 19, 2019

      Just near the base board. I think that the planks are pushed together tight enough that the powder cannot seep through between them.

  • Melba Melba on Feb 24, 2019

    Not sure

  • Melissa Firicano Melissa Firicano on Jul 26, 2020

    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.

  • Joel Joel on Aug 23, 2022

    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.

  • Poa81389626 Poa81389626 on Apr 25, 2023

    What is it?

  • Joel Joel on Apr 25, 2023

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