"Everyone has to define what is important to them environmentally," says Carol Swedlow, president of the Manhattan-based Aronson's Floor and Covering.

Swedlow, who offers green-flooring seminars for builders and architects, says some options are considered environmentally friendly because they come from so-called rapidly renewable resources such as cork and rubber, where trees don't have to be chopped down to harvest materials. Others, such as natural wool, are biodegradable — and because they're also naturally flame-retardant, additional chemicals aren't needed. And many carpet companies now offer products made from a percentage of recycled materials.

"People are asking about it, but I don't think there are a lot of people implementing it," Swedlow. She and other green experts agree that existing co-ops and condos have been slow to use environmentally friendly flooring, in part because boards have to reach a consensus and are often risk-adverse. "You see it a lot more in new construction."

Many carpet companies offer products with varying percentages of recycled materials. Dave Poli, owner Manhattan's Popular Carpet Distributors, says a traditional tufted nylon carpet, like those used for hallways, can start at about $6 or $7 a square yard. Carpets with some percentage of recycled content are about 10 to 20 percent higher , he says. Both last about the same time, roughly 10 years if properly maintained.

One of the industry leaders in green carpeting is the Georgia-based InterfaceFLOR, whose corporate culture commits to environmental causes, from removing toxics from materials to powering mills in part through solar panels and landfill methane gas, says company spokeswoman Reva Revis.

The company's carpet comes in tiles, a more environmentally sensitive choice than broadloom because it allows contractors to reduce installation waste. Also, if one area of the floor is eventually damaged, only a few tiles would need to be removed and replaced. Poli adds that many carpet companies will send their own trucks to pick up old carpet to take back to be recycled.

Yet another type of green carpet is one made of a blend of traditional nylon and bio-material — in InterfaceFLOR's case a substance made with up 15 percent non-food-grade corn. Hybrid carpets have a similar lifespan to traditional and recycled-content carpets. Some of the company's recycled and bio-blend carpet lines cost more than traditional nylon, but others are priced the same.

Poli notes that natural wool is one of the longest-lasting and most durable floorings, pointing out that he uses it for Broadway theater floors, which are subjected to intense foot traffic. He recalls one carpet that lasted 14 years. Wool carpeting might cost about $45 a square yard while a nylon carpet of comparable quality would be about $35. Wool looks better longer, he says, because it sloughs off layers as it ages.

Swedlow swears by wool for hallways and some interior lobby spaces, as long as they are far enough away from the main door. Regardless of the type of flooring, she recommends using walk-off mats that are at least twelve feet long – not the four to six feet that some buildings use – to protect interior flooring from damage and dirt.