In 15 minutes, at least half a dozen people had walked into the Harmons Brickyard store, their reusable or "green" shopping bags in cart or hand.

Dozens more of the bags were for sale near the cash registers at the front of the store. And in the parking lot, signs were posted to remind people not to forget their green bags.

"We've been using these bags for years," said Dan Smith, who was shopping at Harmons, a stack of reusable bags in his cart. "Once we started, we realized how many plastic bags we had been using."

Smith said he discovered reusable bags a few years ago while living in Seattle. The bags have only become widely available in Utah the past year or two, despite efforts by some grocers to introduce them in the early 1990s. Other stores, such as Home Depot and IKEA, also offer reusable bags in Utah.

Shoppers who use the bags say they feel as if they are helping the environment. Likewise, grocers believe the bags are a solution to customer concerns about the limited-use nature of plastic and paper bags.

But are reusable bags really the best way to live "green" while grocery shopping?

Stephen L. Joseph says no. He is legal counsel for San Francisco-based www.SaveThePlasticBag.com and believes people are wrong to believe reusable bags have no environmental impact.

From his perspective, traditional plastic bags are still the "least energy-intensive" option and the "best for global warming and landfills" when compared to paper or reusable bags. He would like to see people generally just avoid asking for bags as much as they can.

But if a person must use a bag, they should opt for a properly filled plastic bag, or bring a reusable bag in preference to paper, according to Joseph.

"Anything proclaimed to be green is not questioned," Joseph said, "but I question it."

Grocers, however, stand by their use of reusable bags.

Whole Foods, for one, has not offered plastic bags in its stores since Earth Day last year. The grocery chain said it believes single-use plastic bags were littering the environment, and its customers were calling for something more eco-friendly.

"Discontinuing the use of single-use plastic bags was a great step in the right direction," said Robin Burton, green-mission representative for Whole Foods. "Though plastic bags are recyclable, the rate is still pretty low in this country."

All the paper bags used in the store are made from 100 percent recycled content material, according to Burton. Likewise, the reusable bags offered by Whole Foods are also made from recycled material, said Burton.