LAGUNA NIGUEL, Calif. (CNNMoney.com) -- Wal-Mart Stores, the world's largest retailer with thousands of big box stores around the world, is looking to make those stores more environmentally friendly.
Speaking at Fortune's Brainstorm Green conference, Lee Scott, chairman of Wal-Mart's (WMT, Fortune 500) executive committee said Monday that the retailer was eyeing stores made of materials that easily revert back to the earth. Scott didn't elaborate on the plan.
A Wal-Mart spokesman said the company is also looking to use more recycled materials in the construction process. The spokesman said the company currently uses rubber in store baseboards that is made partly from old diapers, steel containing recycled components and concrete composed of 20% fly ash, a byproduct of burning coal.
The company has been criticized for its buildings in the past, especially for its tendency to build stores and then move out of them once they get too small. The empty buildings can become a headache for communities.
Scott said Wal-Mart realizes the impact this can have on towns, and is working hard to fill the spaces with other businesses once Wal-Mart moves out. He said the company has just over 100 empty stores out of over 3,000 buildings in total. That's down from over 300 empty stores a few years back.
He also said Wal-Mart has a plan to build more stores in urban areas, but that the company is facing opposition from certain segments of society that didn't want it to succeed.
'"That would be the unions," chimed in Time Inc. editor-in-chief John Huey, who was interviewing Scott at the green business conference. Unions have criticized the company for paying its employees too little.
Scott's comments were part of a wide-ranging talk with Huey on the company's plan to green up its operations.
Wal-Mart, once vilified by environmentalists for its large ecological footprint, has recently been praised in the green community for its efforts, which include commitments to use 100% renewable energy, generating zero waste at its stores and requiring its suppliers to measure their greenhouse gas output.
"The federal government isn't asking a Chinese company if they've done their carbon footprint, but Wal-Mart is," Kert Davies, research director at Greenpeace, said in an interview before the conference. "They are way ahead when it comes to this."
Davies also said the company had made big strides in reducing its energy consumption, although he said they could still do more when it comes to selling sustainable seafood and lobbying the federal government for stronger greenhouse laws.
Scott said the transition to a greener Wal-Mart did not go exactly as executives expected. He thought they would have to convince the company's rank-and-file employees on the merits of sustainability, but many of the younger workers were wondering why they hadn't done it sooner.
"We thought we were leading, but we weren't," he said. '"There were a lot of young people who were wondering when we were going to do things differently."
It's not just about saving the planet - some eco changes have paid off handsomely for the company.
Scott said repacking on certain toys has resulted in 215 fewer containers the company needs to ship each year. And an emphasis on loading trucks more efficiently has shaved 38% off the company's fuel bill.