(CNN) -- Officials are looking into claims that Chinese-made drywall installed in some Florida homes is emitting smelly, corrosive gases and ruining household systems such as air conditioners, the Consumer Product Safety Commission says.

Gas emitted from defective drywall corrodes copper wiring, turning it black, some Florida homeowners say.

The Florida Health Department, which is investigating whether the drywall poses any health risks, said it has received more than 140 homeowner complaints. And class-action lawsuits allege defective drywall has caused problems in at least three states -- Florida, Louisiana and Alabama -- while some attorneys involved claim such drywall may have been used in tens of thousands of U.S. homes.

Homeowners' lawsuits contend the drywall has caused them to suffer health problems such as headaches and sore throats and face huge repair expenses.

The drywall is alleged to have high levels of sulfur and, according to homeowners' complaints, the sulfur-based gases smell of rotten eggs and corrode piping and wiring, causing electronics and appliances to fail.

"It's economically devastating, and it's emotionally devastating," said Florida attorney Ervin A. Gonzalez, who filed one of the lawsuits. It would cost a third of an affected home's value to fix the dwelling, Gonzalez said.

"The interior has to be gutted, the homeowners have to continue paying mortgages, and they have to pay for a [temporary] place to live," Gonzalez said.

The CPSC has been investigating claims in Florida for more than a month, according to commission spokesman Joe Martyak. He would not confirm whether CPSC is checking other states or reveal how many cases it is probing.

The Florida complaints generally involve homes built or renovated in 2005 and 2006, when a building boom and post-hurricane reconstruction caused a U.S. drywall shortage that spurred builders to turn to imports, Martyak said.

The allegations come after a number of recent safety problems with other Chinese exports, ranging from toys to pet food.

Dick and Nancy Nelson, who say the Florida retirement home they bought new in 2006 has Chinese-manufactured drywall, contend all their appliances with copper are failing, according to CNN affiliate WFTS-TV.

"The washing machine, the dryer, the microwave, a refrigerator -- these are all brand-new appliances, and they're breaking down," Nancy Nelson of Palmetto told the Tampa station. The Nelsons are among those who have complained to the state health department.

In a neighborhood in Homestead, Florida, owners of homes with Chinese-manufactured drywall say the dwellings smell like rotten eggs, especially on humid days, according to CNN affiliate WPLG-TV. Watch residents display corroded wiring »

Electronics and appliances with copper components stopped working in short order, and copper pipes and wiring turned black, homeowners told the Miami station.

"My dream has turned into a nightmare," one of the homeowners, Felix Martinez, told WPLG-TV. He said he closed on the home in August 2006.

Michael Foreman, head of construction consulting firm Foreman & Associates in Sarasota, Florida, said he's been investigating drywall complaints in that state since last year and is sharing information with at least one group of lawyers preparing lawsuits on the matter. Based on shipping records, Foreman estimates the United States in 2006 and the first two months of 2007 imported enough drywall from Chinese manufacturers named in lawsuits to produce at least 50,000 homes at a size of 2,000 square feet each.

Florida ports alone took in enough of that drywall during those 14 months to build 30,000 homes of that size, he estimated, citing records he obtained from the Port Import Export Reporting Service, a company that collects information on cargoes entering and leaving U.S. ports. Foreman said he has yet to see import records from 2004 and 2005, years covering what he said was a building boom with a high demand for drywall.

This house in Homestead, Florida, was gutted after allegedly defective Chinese-made drywall was found there.

Two Florida attorneys involved in separate class-action lawsuits, Gonzalez and Jordan Chaikin, said they, too, believe shipping records indicate tens of thousands of residences in the United States, with a good chunk of them in Florida, may have drywall from the manufacturers.

"The breadth of this thing is a lot bigger than people think," said Chaikin of the Parker Waichman Alonso law firm in Bonita Springs. Chaikin said the problem is perhaps more easily recognizable in Florida because humidity exacerbates it.

An Alabama-based homebuilder alleges that Chinese-manufactured drywall in 40 houses it built in 2005 and 2006 -- 32 in Alabama and eight in Florida -- caused corrosion or odor problems. The builder, Mitchell Co., has filed a class-action lawsuit in Florida against certain manufacturers, attorney Steve Nicholas said.

"We filed on behalf of builders because we believe ... they're going to be the ones with the initial loss" to fix the problems, said Nicholas, of Alabama law firm Cunningham Bounds.

In Miami, Gonzalez filed his class-action lawsuit for homeowners this month. The suit names as defendants three China-based drywall manufacturers that the plaintiffs say are affiliates of Germany-based manufacturer Knauf Gips KG. Knauf Gips KG was also named, along with three Florida developers and two distributors.

The Miami suit seeks compensation and medical monitoring of the homeowners.

Joerg Schanow, a member of Knauf Gips' board, said in a telephone interview with CNN that the Chinese manufacturers named in the suit are part of Knauf Group, but not controlled by Knauf Gips KG.

"We here in Germany do not manufacture Chinese drywall. [Knauf Gips KG has] never asked companies to manufacture Chinese drywall for us or on our behalf. And there is no relationship at all," Schanow said. "I'm confident we will rebut this."

On its Web site, the company says the Knauf Group operates 150 factories worldwide, including the three Chinese production facilities named in the lawsuit.

One of the Chinese manufacturers named in the suit, Knauf Plasterboard Tianjin (KPT), said in a statement released through U.S. representatives that tests by an expert toxicologist it retained found "no associated health risks with the KPT product." KPT is still investigating whether its product has caused any corrosion, spokeswoman Yeleny Suarez said.

In a separate statement released through KPT's U.S. representatives, lawyers said there is no basis for the other two China-based manufacturers, Knauf Plasterboard Wuhu and Knauf Plasterboard Dongguan, to be part of the lawsuit and the manufacturers "will defend themselves vigorously."

At least two other class-action lawsuits -- one in Florida, the other in Louisiana -- name as defendants Knauf Gips, KPT and a Chinese drywall manufacturer not connected to Knauf, Taishan Gypsum Co. In a telephone interview with CNN, a Taishan Gypsum representative said "it's impossible that our products are found to emit poisonous gas in America," adding that the company didn't export to the United States.

Martyak declined to say which Chinese manufacturers the CPSC is investigating.

And Foreman cautions that not all Chinese drywall manufacturers who exported to the U.S. are accused of supplying a defective product.

The Louisiana suit, filed by the Becnel Law Firm of Reserve, Louisiana, claims defective Chinese drywall was installed in a home in Pearl River.

The Louisiana Department of Health and Hospitals has received one complaint related to the drywall issue by phone, J.T. Lane, the department's deputy chief of staff, said Wednesday.

The department is in touch with the Centers for Disease Control and Prevention and the Florida Health Department, and is "trying to determine what might be the public health impact for Louisiana and what the most appropriate response to this is," Lane said.

CNN's Luo Yingying contributed to this report.

All About Florida • China • U.S. Consumer Product Safety Commission • Florida Department of Health