The federal government said Monday that it has found a "strong association" between problematic imported Chinese drywall and corrosion of pipes and wires, a conclusion that supports complaints by thousands of homeowners over the last year.

In its second report on the potentially defective building materials, the U.S. Consumer Product Safety Commission said its investigation also has found a "possible" link between health problems reported by homeowners and higher-than-normal levels of hydrogen sulfide gas emitted from the wallboard coupled with formaldehyde, which is commonly found in new houses.

The commission, along with the Environmental Protection Agency and the Centers for Disease Control and Prevention, continues to study the potential health effects, and the long-term implications of the corrosion.

"We can say that we believe that there's a number of different chemicals that when brought together can be related to some of these irritant health effects that we've been getting reports of," said CPSC spokesman Scott Wolfson. "But we're still working toward that exact nexus."

The commission said it can now move forward with additional studies to identify effective remediation of the problem and potential assistance from the federal government. However, Warren Friedman of the U.S. Department of Housing and Urban Development said it's too soon to discuss specifics of any financial assistance homeowners could get.

The Formaldehyde Council, a trade group, said there is no scientific evidence to support the theory that the two chemicals can combine to sicken people.

Betsy Natz, the group's executive director, called it "irresponsible to speculate that formaldehyde and hydrogen sulfide can act in a synergistic ... manner to cause irritant effects in human beings at the low levels found in the CPSC study."

The CPSC has spent more than $3.5 million on the studies, and has received more than 2,000 homeowner complaints from 32 states, Washington, D.C., and Puerto Rico, in what is now the largest consumer product investigation in U.S. history. Most of the complaints have come from Florida, Louisiana, and Virginia. Wolfson said the CPSC has committed nearly 15 percent of its staff to the issue.

The results released Monday came, in part, from a 51-home indoor air quality study.

However, officials cautioned that not all Chinese drywall is necessarily problematic and that homes with American-made drywall also are being studied.

"Not all drywall is alike," said Jack McCarthy, president of Environmental Health & Engineering Inc., the firm hired by the government to perform the air quality tests. "It depends on what it's made of, not necessarily the country where it came from."