Used carpet as path mulch and weed smother

I'm thinking about using old carpet to do three things:

As permanent paths, with a top layer of wood chips, to keep down weeds, mud, and ruts in my large annual garden.

As temporary covers put down to suppress weeds, conserve moisture, and aid decomposition of mulch until I can replant a bed, generally a month or less.

As a way to kill off a rye cover crop in the spring, leaving a dead mulch on the surface for planting through.

Should I worry about toxins? Are there any other problems I'm not thinking of in any of these applications?

Before you get into it in a huge way, see how quickly the plastic carpet breaks down in your climate.  Here in TX plastic breaks down very fast into nasty tiny pieces which are almost impossible to clean up.  Up there near the sky you don't get much protection from UV rays which are the thing that break down the plastic.  I'd be seriously worried about a nasty mess of tiny plastic bits in my soil.

I would not use it even under wood chips, because it will prevent the wood chips from interacting with the soil to provide a habitat for fungi and other good guys.  I think the chips alone will do the job.

Tyler, you're description really makes me shudder. It reminds me of when I first moved in my mom and I used cardboard to smother the grass. She assured me we didn't need to take the tape off. I followed her lead because she's been gardening so long, and I really wasn't experienced/knowledgeable. I still find plastic tape in my garden. It's horrible and nasty and hard to pick out. Tiny pieces of plastic carpet backing sound like my worst nightmare!

Do you know what the carpet is made from?  I think an all wool or cotton with no backing might be nice in the garden and decompose along with the other mulches.

We lived where someone years before had laid down some synthetic shag carpet in the garden and the mesh backing and all of the 'shag' survived, the glue was gone so it was just bits and pieces at that point and impossible to retrieve....probably still there today.  

When I was weaving I put several worn cotton rugs that I had made down layered with the mulch and they were pretty much gone in a year or so.  I always liked the idea of making compostable weavings.

I had an old old woven straw/grass? rug that I used as a mulch once also...fast decomposition.

Should I worry about toxins?

 Yes, I think so, many carpets are probably treated with 'stuff' ...I don't know what though.

Good points about UV problems.

I would think that under a wood chip path, the UV wouldn't be a problem. And I was actually thinking about putting chips under the carpet as well, to provide fungal benefits.

What kind of waste material could I use as a temporary weed/ cover crop smother? I tried using tarps, which worked, but the pooled water on top which was hard to get off, and walking on them to broom the water off poked holes in them.

I used cardboard, but that looked messy, broke down quickly, and even large sheets were too small for maximum benefit. And I don't know how I'm going to store the stuff.

Someone in another thread mentioned using old rubber roof sheeting, though I imagine it's a little harder to source than used carpet.  I think it's the same as pond liner, and is UV stabilized.

http://www.repurposedmaterialsinc.com/roofing-rubber/