Getting a better deal drives most people to buy a new cellular phone in the U.S., with only a minority of consumers considering the enormous impact throwing away the old phone has on the environment, a study released Friday showed.

In a poll of 20,000 consumers in 20 of the world's top economies, nearly 8 out of 10 said cost savings and more favorable contract terms was the most important reason for upgrading their mobile phones, according to Global Market Insite Inc., which does market research for businesses. The same ratio applied to U.S. consumers.

Less than 1 out of 10 U.S. consumers, however, considered the environmental impact of tossing away the old phone, Seattle-based GMI said. In the United Kingdom, the percentage was 12 percent. In Asia, the numbers were better, with 20 and 26 percent of consumers in India and China, respectively, saying environmental reasons could prohibit them from upgrading.

U.S. consumers' attitudes toward the environment has a huge impact, considering that Americans throw away about 100 million cellular phones a year, which amounts to 50,000 tons of waste, according to Inform Inc., an independent research group that examines the effects of business practices on the environment.

Wireless carriers, which sell a majority of cellular phones in the U.S. with their service plans, have a voluntary recycling program run through the Cellular Telecommunications and Internet Association, an industry group based in Washington, D.C.

"(The CTIA) has set up a take-back program, but the problem is the amount their taking back is miniscule compared to the amounts that are being thrown away," Bette Fishbein, senior fellow at Inform, said.

On average, consumers in the U.S. and many other countries upgrade their phones every 18 months; yet wireless carriers in the U.S. have done little to make the public aware of how to recycle their old phones.

"The outreach to the public is very, very poor," Fishbein said.

Similar to computer and other electronic devices, cellular phones contain heavy metals and poisons, such as arsenic, lead and mercury, that are proven to cause cancer and birth defects. The toxins are released into the environment when phones are dumped in landfills or burned in incinerators.

While computers contain more of the toxins then handheld devices, many more of the latter is being sold and thrown away.

"What we're seeing are more and more products like cellular phones, made with toxic components, used for a very, very short time and then thrown away," Fishbein said.

What's needed to combat the problem is a recycling of the toxins, so they can be used in new phones; and a refurbishing of old phones, so they can be resold, Fishbein said. In addition, Inform favors government regulations that would require wireless carriers and other companies in the mobile-phone industry to recycle old phones.

Recycling mandates exist today in the European Union, Japan, Korea and Australia, with China moving in that direction, Fishbein said.