Is American-made drywall causing the same problems that have been linked to tainted Chinese-made drywall?

The Consumer Product Safety Commission released a report this week that was supposed to help answer that question, but the report has so many gaps that homeowners, lawyers and drywall experts say it has only added to their confusion and frustration.

The agency studied 11 homes which, according to their owners, were built with U.S.-made drywall but are exhibiting problems typically associated with Chinese drywall. The report said drywall in five of the houses was "consistent with problem drywall," which releases so much sulfur gas that it causes respiratory problems and corrodes wiring. But the CPSC said it couldn't draw any conclusions about American drywall from its investigation, because it couldn't confirm that all the drywall in the homes was made in the United States. To do that would require "further extensive investigation and detailed documentation of the origin of the drywall in these homes," the report said.

The CPSC did not respond to questions about why it did not take those extra steps. The agency refused to make a CPSC official available to discuss the report.

The CPSC also decided not to conduct additional tests on four homes where the results were inconclusive, even though the company that tested the homes for the CPSC recommended they be done. Many experts say those tests, called chamber tests, are the most reliable way to measure how much sulfur gas a piece of drywall is producing. But the report said the agency didn't authorize those tests, or any further study of American drywall, because of "the relatively limited number of homes affected, the uncertainty concerning the drywall's origins (and) agency resource constraints."

Jack Frost, a biochemist whose company has tested drywall in nearly 3,000 homes, said the CPSC's decision not to authorize the chamber tests and not to figure out who manufactured the drywall in the 11 homes was "nuts."

"How they have all these brilliant scientists and do a report like this is just incomprehensible to me," Frost said.

Brenda Brincku, whose Alva, Fla., home was among those tested by the CPSC, was also mystified by the report. She and her family moved out of their home in 2009 after they began having bloody noses and headaches and their electronic equipment began failing. Now they're struggling to pay rent and keep up their mortgage payments. Their financial problems are so bad, Brincku said, that she couldn't afford to attend her daughter's wedding in the Virgin Islands.

The CPSC report said tests showed that the Brinckus' drywall wasn't producing sulfur gases. But according to the report, the contractors who conducted those tests said that because the home's wiring was corroded, chamber tests should be done to make sure the board was safe.

When Brincku asked the CPSC why it didn't do the chamber tests, she said she was told the agency couldn't afford to take that extra step.

"I just couldn't believe it. 'You don't have money to look into this? You had the money for the Chinese drywall problem, didn't you?' " Brincku said. "But they insisted that they couldn't do chamber tests because they are out of funding."

The Brinckus say their house was built with two brands of U.S.-made drywall and that tests they commissioned show it is producing high levels of sulfur gasses. They have filed a lawsuit against one of those manufacturers, Charlotte-based National Gypsum, which has told ProPublica that its tests showed that the Brinckus' drywall is not producing sulfur gas.

Craig Weisbruch, National Gypsum's senior vice president for sales and marketing, said the CPSC's failure to trace the origin of the drywall in the homes made the report meaningless.

"Almost any time that you have one of these Chinese drywall problems in a house you are going to find American drywall in the house too given the nature of construction," he said. "But because of the method they used, we can't tell what kind of board they tested."

National Gypsum has said that it found no Chinese drywall in the Brincku home.

Pamela Gilbert, who was a CPSC executive director in the Clinton administration, said it was disappointing that the agency has decided not to continue studying American-made drywall.

"It's a shame, because so many resources have been spent on Chinese drywall problems, and the CPSC was unable to move forward with that because the perpetrators were in China and unreachable," said Gilbert, who is now a partner with the law firm Cuneo, Gilbert & LaDuca, which represents some of the nearly 100 homeowners who are suing National Gypsum. "Here you have a situation where there is a problem and American companies could be pursued by CPSC, but they have chosen to cut the investigation short."

The CPSC's report on American drywall is the latest in a string of government reports and announcements that have confused and disappointed families who say their homes have been contaminated by defective drywall.

In March, the CPSC reversed its earlier recommendation that the wiring in the homes be removed because it was a potential fire hazard. That decision conflicts with guidelines created by Judge Eldon E. Fallon, who is presiding over the massive Chinese drywall litigation playing out in New Orleans federal court. Fallon's guidelines still recommend removing all the wiring.

In February, a spokesperson for the Centers for Disease Control told CNN that it will not pursue a scientific study on the long-term health effects of living in a home built with contaminated drywall because such a study would take too long, cost too much money and would not produce conclusive results.

Also in February, drywall experts criticized the CPSC for not using chamber tests to help determine whether the drywall in homes on a North Carolina military base could have led to the deaths of 11 infants. The death toll has since climbed to 12, and the military is still searching for an underlying cause.