found white powder under carpet pad

[Whitenack]

Ripped up the old carpet today and found a white powdery substance under the carpet pad.

Is this mold/mildew?

Or is it a moisture absorbent agent put down by the installer?

What should I do?

[twelvepole]

It's probably the deteriorating latex backing along with dust and grit that worked its way downward. Simply sweep up the dust.

[Carpets Done Wright]

Along with carpet deoderant power that the vaccum is suppose to suck up, but doesn't get it all. (if any has ever been used)

[HotinOKC]

Carpets,

I heard that rug backings have or used to have, cement type of products in the manufacturing process and this could explain why people find all the dirt/powder? Any truth to that?

[twelvepole]

I am surprised that all was found was white powder. I used to sell carpet. Keeping the warehouse floor clean was a weekly project. Sand from latex backing and black dust from carpet cushion were always a problem.

I have lived in homes where I removed carpet, there was always a layer of dust, powder, grit, etc. on the subfloor. The high traffic areas were the worst for grit that filters down through carpet and cushion. Dry carpet cleaners methods, as indicated, will deposit beneath cushion because most household vacuum cleaners are not powerful enough to retrieve the powder. They are also not powerful enough to retrieve the grit.

[youngmontana85]

I am continously vacuuming up a white powdery substance that leaves a slight burning smell in the air for over 4 months now. I vacuum my carpet about once a week and its been coming up continously over this time. Spilling water on the carpet also leaves a stain for about a week and then it gradually goes away. Anyone have a clue as to what this could be I'd greatly appreciate it. My landlord keeps trying to dodge the fact it could be the back of the carpet coming up which i think it mght be.

[twelvepole]

Have you had the carpet professionally cleaned? If living in a rental, who knows what previous owners put on the carpet to deodorize. The powder remains in the carpet and can work its way through the cushion to subfloor below. Professional cleaners have the equipment with enough suction to remove the powder from carpet and to clean and sanitize it.

The burning smell may be from where the powder is getting on the motor housing and heating up. Spills on carpet should be blotted up immediately to prevent staining.

[roxboro11]

I am posting because I have the same question, and am looking for an answer.
I have a fine greenish/gray/white powder that seems to constantly accumulate under 2 heavy wool rugs that I purchased 2 years ago. I KNOW that it can't be carpet freshener, because I don't even own any such product, and because none of the other area rugs in my house have ever exhibited this issue, I know it is not related to house dust.
My only conclusion is that (clearly) it must be coming from the rug itself - possibly a deterioration of the backing as was suggested by a previous post.
Anyone else have any other information on this??