Updated

Earth shoes are back, and they're not just for the granola types any more.

From sneaker giants such as Adidas (www.adidas.com) through crunchy cobblers like Simple Shoes (www.simpleshoes.com) and on to high-end designers like Hetty Rose (www.hettyrose.co.uk), just about every footwear designer around has dipped a toe into the environmentally-friendly pool.

Timberland has taken things the farthest. In 2006, the company attached a "nutritional" label to all its wares, listing everything from where the product was made to environmental impact (determined by "life-cycle analysis" based on energy use) and community impact (everything from child labor to how many hours employees volunteer in their community).

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But with all this green-heeling going on, the questions remains: Is this marketing propaganda, or real eco-progress?

It's a fair question. Traditionally, shoes are made from some of the most toxic stuff on earth, but with consumers driving the market toward greater durability and lower prices, change isn't easy to come by.

Take leather. For durability reasons, most shoes start out as animal hides, but according to Betsy Blaisdell, Timberland's manager of environmental stewardship, "there's no good environmental solutions for leather."

Remember Julia Roberts in "Erin Brockovitch" and John Travolta in "A Civil Action?" Both movies were based on real events, and both disasters were caused by tanneries.

That's because tanneries use everything from mineral salts to formaldehyde to coal-tar derivatives to soften their skins, with the metal chromium being the worst offender.

Ninety-five percent of the world's leather is chrome-tanned, the by-products of which pollute both air and water, causing everything from bronchitis to lung cancer.

To sidestep this problem, companies such as Patagonia (www.patagonia.com) investigated vegetable-based substitutes. They soon found that while organic tans may be better from a chemical standpoint, they're even worse for overall ecology.

"We still make about 10 percent of our shoes that way," says Craig Throne, general manager for Patagonia Footwear, "but [accounting firm] Deloitte and Touche did an independent audit of vegetable tans and found they use more energy and waste more water than traditional methods."

So Patagonia decided to work instead with ISO-14001 certified tanneries and to get involved in the Leather Working Group. (The International Standard Organization's 14001 designation is a voluntary commitment to eco-friendly policies, but not a technical standard.)

Started in 2006 by Timberland (www.timberland.com), the Leather Working Group is an independent third-party multi-brand environmental audit for tanneries overseen by the British BLC Leather Technology Centre (blcleathertech.com).

While the organization is still getting up to speed, its goal is to establish an industry-wide ecological measuring stick so companies can shift their businesses to approved tanneries. Several tanneries in Asia have already received the LWG's "Gold" and "Silver" classifications.

To be approved, tanneries must institute a number of new methods — lower-temperature dyes and dryers, more efficient processing rollers and sprays, a return to enzyme-based dehairing methods and recycling of waste products, including using organic sludge to produce biofuel.

Other companies, such as Etnies (www.etnies.com) and Ecolution (www.ecolution.com), have tried to remove leather altogether, going in for everything from bamboo and wool to cork and hemp, but natural fibers tend to get dirty quickly and wear out sooner.

And animal skins are only part of the problem. These days, shoes are loaded with plastics, with polyvinyl chloride (PVC) the biggest nightmare of all.

"Every step of the way, PVC is the worst plastic for our health and our environment," says Mike Schlade of the Falls Church, Va.-based Center for Health, Environment and Justice.

That new-sneaker smell, like that new-car and new-record smell, is actually the off-gassing of PVC. Unfortunately, that odor is packed with dioxins, which cause cancer, birth defects and endocrine disorders at all levels of the food chain.

Not only is PVC deadly to humans and other animals, it's very difficult to reuse. In 1998, the Association of Post-Consumer Plastics Recyclers declared efforts to recycle PVC futile and labeled it a contaminant.

An even bigger problem may be the phthalates — solvents used to soften up PVC — which the EPA and Centers for Disease Control have linked to reproductive problems in both animals and humans.

The good news is that many shoe companies have begun removing PVC from their wares altogether.

According to a 2001 Greenpeace study, Adidas phased-out PVC from everything but its high-performance shoes in 2002 and its fraternal rival Puma in 2003. Asics and Nike have removed it completely.

Even more important, but less visible, is a return by shoemakers from glues to stitched construction. Since standard shoe glues are highly toxic, and water-based substitutes too finicky for mass production, a number of companies have returned to old school needle-and-thread methods.

Patagonia may be king in this corner: Fifty percent of its products rely on heavy-stitch construction. Timberland is also seriously onboard, and Nike just introduced its Jordan XX3 — the 23rd annual iteration of the legendary Air Jordan sneaker — incorporating everything from re-engineered lace design to a newly developed, patent-pending 3-D stitching machine to remove the use of adhesives.

The Jordan XX3 is the frontrunner in Nike's "Considered" program, a company-wide attempt to reduce greenhouse gases and make more sustainable designs with all footwear lines scheduled to meet "Considered" standards by 2011.

Along those lines, Nike also just introduced Phoenix Suns star Steve Nash's "Trash Talk" sneaker, made from mostly manufacturing waste.

Lastly, soles must be saved. Synthetic rubber — made from petroleum products — is the industry standard for soles, so recycling that rubber seems like the obvious solution.

Unfortunately, as Patagonia's Craig Throne points out, "30 percent recycled rubber seems to be the upper limit. Once you get past that, shoes tend to fall apart."

That casts doubt on Simple Shoes' claim that its Green Toe line is made from 50 percent recycled rubber. It also points to a much deeper issue.

According to Annie Leonard's online documentary "The Story of Stuff," (www.storyofstuff.com), sponsored by the Tides Foundation and Funders Workgroup for Sustainable Production and Consumption, the average lifespan of the consumer products we buy is six months. In other words, those shiny new sneakers you now like so much may be heading for the landfill in just half a year.

With nearly 32 billion shoes manufactured annually (according to ECEconomy.com), the real heart of the problem may be fashion far more than function.