The toilet paper roll is about to undergo its biggest change in 100 years: going tubeless.

On Monday, Kimberly-Clark, one of the world's biggest makers of household paper products, will begin testing Scott Naturals Tube-Free toilet paper at Walmart and Sam's Club stores throughout the Northeast. If sales take off, it may introduce the line nationally and globally — and even consider adapting the technology into its paper towel brands.

No, the holes in the rolls aren't perfectly round. But they do fit over TP spindles and come with this promise: Even the last piece of toilet paper will be usable — without glue stuck on it.

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Suddenly, there's news in the $9 billion — but stagnant — toilet paper market. More important, it's got a "green" halo.

The 17 billion toilet paper tubes produced annually in the USA account for 160 million pounds of trash, according to Kimberly-Clark estimates, and could stretch more than a million miles placed end-to-end. That's from here to the moon and back — twice. Most consumers toss, rather than recycle, used tubes, says Doug Daniels, brand manager at Kimberly-Clark. "We found a way to bring innovation to a category as mature as bath tissue," he says.

He won't disclose the tubeless technology used but says it's a special winding process. A similar process is used on tissue the company sells to businesses but not to consumers.

Behind the marketing push is a growing consumer demand for environmentally friendly products.

One environmentalist applauds the move. "It's a positive example of how companies are seeking creative ways to reduce environmental impact," says Darby Hoover of the Natural Resources Defense Council. But more relevant than nixing the tubes would be more recycled content in its paper, Hoover says. While Scott Naturals normally has 40% recycled content, this test product does not — but future versions will, Daniels says.

Hoover says she hopes other toilet tissue makers follow Kimberly-Clark's lead. How soon that may happen is unclear. Procter & Gamble, maker of top-seller Charmin, declined to comment.