Biodegradable products may not be as good for the environment as advertised.

New research from North Carolina State University shows that biodegradable materials actually release a powerful greenhouse gas into the atmosphere when they break down.

“Biodegradable materials, such as disposable cups and utensils, are broken down in landfills by microorganisms that then produce methane,” said Morton Barlaz of North Carolina State University, and co-author of the study.

“Methane can be a valuable energy source when captured, but is a potent greenhouse gas when released into the atmosphere.”

The Environmental Protection Agency (EPA) estimates that 35 percent of municipal waste goes to landfills that will capture methane and use it for energy. The agency also estimates that while another 34 percent of landfills capture methane and burn it off-site, 31 percent allow the methane to escape into the atmosphere.

Making matters worse, the Federal Trade Commission (FTC) mandates that man-made biodegradable materials decompose within “a reasonably short period of time” following their disposal.

This rapid degeneration guideline is a problem since federal regulations do not require landfills to set up methane collecting systems for at least two years after the waste is buried, leaving significant time for methane from biodegradable materials to seep into the atmosphere.

Due to these factors, the study calls for a slower rate of biodegradability in products so that landfills have adequate time to put methane collecting systems in place.

“If we want to maximize the environmental benefit of biodegradable products in landfills,” Barlaz said, “we need to both expand methane collection at landfills and design these products to degrade more slowly — in contrast to FTC guidance.”

This study was published online in the May 27 issue of Environmental Science & Technology. The research was supported by Procter & Gamble and the Environmental Research and Education Foundation.