550 million

Pounds of drywall made in China that have been offloaded at U.S. ports since 2006, enough to build 60,000 homes, according to a HeraldTribune.com news story. Gases emitted by some Chinese drywall have been linked to corrosion of electric equipment, including air conditioners, appliances, and electronics, and damage to pipes.

Homes in Florida have experienced the most problems, but properties in a dozen other states might also be affected. Some homeowners also claim that drywall is causing health problems. Senator Bill Nelson, a Democrat from Florida, has called on the U.S. Consumer Product Safety Commission and Environmental Protection Agency to look into the possible toxicity of Chinese drywall.