“There could be 60,000 to 100,000 homes that are worthless and have to be ripped completely down and rebuilt,” said Arnold Levin, a Philadelphia lawyer and co-chairman of the plaintiffs’ steering committee.

While tainted Chinese imports like toothpaste, pet food and baby formula have been quickly removed from store shelves, drywall is installed throughout homes and does not lend itself to a quick fix.

This month, the Consumer Product Safety Commission, whose investigation into Chinese drywall is the largest in its history, will release the results of a study to determine why the drywall is causing the problem, and what kind of remediation programs might be effective.

Image Bill Morgan had to abandon his newly built dream home in Williamsburg, Va., blaming drywall for corrosive fumes that attacked metal objects. Credit... Casey Templeton for The New York Times

Already, the commission has sent six investigators to Chinese gypsum mines and to meet with the government there. The Chinese government’s counterpart to the federal safety commission sent two of its experts here to inspect affected homes.

The commission is also making sure that no more Chinese drywall comes into the country.

“Our ports are on alert,” said Inez Tenenbaum, chairwoman of the commission. “They are not letting any in. The market, too, has corrected. No one wants Chinese drywall.”

Even President Obama is being pressed by members of Congress to raise the issue on his November trip to China  the loudest cry coming from Senator Bill Nelson, Democrat of Florida, who has traveled to China on his own to learn more about the drywall problems.