YELLOWSTONE NATIONAL PARK - If you've stayed at one of Yellowstone's hotels or lodges recently, you may have wondered what happened to the soap in your guest room. The standard bar shape has been replaced with an odd, oblong, donut-like incarnation.

The new design is not some new marketing concept. It has a much more practical and environmentally conscious purpose.

"The hole in the soap cuts out a lot of the volume that would normally be thrown away," said Beth Pratt, director of environmental affairs for Xanterra Parks and Resorts, Yellowstone's hospitality and guest services concessionaire.

The soap with a hole in it - packaged in a recycled cardboard container, of course - is one of many eco-friendly initiatives and sustainability programs under way at Yellowstone and Grand Teton national parks, as well as Devils Tower National Monument.

From aggressive and ambitious recycling policies, to the use of hybrid vehicles, to innovative soap designs, Wyoming's parks are living up to their charge of preserving the country's natural resources.

In recent years, decrees have rained down from the Department of Interior urging park officials to implement environmentally friendly practices, and leave as light of a footprint on the earth as possible. Wyoming's parks, Yellowstone in particular, have been ahead of the curve.

"We didn't need someone in Washington to issue a directive," Yellowstone spokesman Al Nash said. "We already understood the importance. We stepped out in this direction on our own."

Nash pointed out that the park began experimenting with biodiesel (a non-petroleum-based fuel) more than a decade ago. Today, everything in the park that operates on diesel runs on a biodiesel blend.

According to Jim Evanoff, the park's environmental protection specialist, the use of biodiesel throughout the park results in a net reduction of 500 metric tons of carbon dioxide emissions annually.

Evanoff said another major initiative in Yellowstone has been its waste reduction policy. Three years ago, the park's 3,000 tons of garbage per year ended up in a landfill. Today, 75 percent of that waste is diverted from the landfill.

"We're anticipating that number to be 80 percent this year," Evanoff said.

The key to keeping garbage out of the landfill, both Pratt and Evanoff said, was the opening of a regional compost facility. "That allowed us to see our garbage and determine what we could eliminate," he said.

After the waste was inspected, it was clear that shampoo and conditioner bottles were significant contributors to Yellowstone's garbage. So Xanterra switched to a compostable corn-based plastic, eliminating an estimated 280,000 bottles from ending up in the landfill.

Another item that kept showing up in large quantities was propane gas canisters, which could not be recycled. But park officials teamed up with an engineering company in Montana to design a piece of equipment that purges the canister of any remaining fuel and then punctures and crushes the propane container, converting it to a recyclable metal.

'There's a pride here'

While Yellowstone has been at the forefront of the environmental movement, it is not alone in its sustainability programs. Grand Teton has its share of environmentally friendly programs and initiatives, too.

Last year, the park moved from traditional sources of energy to 100 percent "green" power from Lower Valley Energy. Now, the electricity that powers the park's administration buildings and visitor facilities comes from renewable resources: wind, solar and water.

In addition, the park is home to the first building constructed in a national park to earn platinum-level Leadership in Energy and Environmental Design, or LEED, certification: the Laurance S. Rockefeller Preserve Center.

Jackie Skaggs, the park's public affairs officer, said that to supplement some of these larger projects, the park has taken more modest eco-conscious steps, including promoting staff car-pooling and replacing incandescent bulbs with more energy-efficient compact fluorescent bulbs.

She said the park's employees embrace the roles of being good stewards of the park and the earth.

"There's a pride here," Skaggs said, "that we're part of the solution, not part of the problem."

Sustainability is on the minds of park officials on the other side of the state as well. At Devils Tower National Monument, hybrid vehicles have been ordered by management to replace older, less fuel-efficient vehicles.

Also, according to Mark Biel, chief of resource management at Devils Tower, electric vehicles are being considered as more eco-friendly options for in-park vehicles.

"We're trying to be as earth-friendly as possible since that's what the monument is here for," he said.

For Skaggs and Evanoff, it's important to teach the public about how they can make more "green" decisions in their daily lives.

Evanoff said Yellowstone's management takes the educational component of its sustainability programs seriously. The goal, he said, is to have the park's visitors "take what they learn back to their communities."

Perhaps an unusually shaped bar of soap is a good place to start.