The commission has the authority to issue a "stop sale," which would effectively ban a product from being sold or imported. It also can issue a formal recall, which would require that Chinese drywall be removed from all affected homes.

Word of the federal investigation came as the owners of one of six homes being repaired by Miami-based Lennar Corp. in Manatee County's Heritage Harbour development ordered that all work be halted on their house.

Dan and Janet Tibbetts of Montauk Point Crossing worry that wood studs and framing in the house still emit an odor even after the Chinese drywall was removed. They also want an independent inspector to evaluate the home -- including examining all metal components for signs of damage -- before Lennar rebuilds the walls.

The last-minute order was sent as Lennar contractors were on the verge of installing new drywall Monday.

Through a spokesman, Lennar division president Darin McMurray said, "Although Chinese drywall has been found in homes constructed by many South Florida builders, Lennar has been by far the most proactive in working with our homeowners to fix the problem. We will continue to work closely with our homeowners to address all of their concerns during the repair process."

The Tibbettses have hired Sarasota attorney Alan Tannenbaum, who specializes in construction law and who faxed McMurray the formal cease-and-desist order Monday afternoon.

"We think there's a step that has been missed," Tannenbaum said. "All the drywall was pulled out, and that was a good start. But there needs to be an evaluation of what damage this material has wrought on the home -- an examination of the metals and the framing to see whether they are OK before things are closed up. We also need to figure out what's causing the continued stench."

Several experts believe the drywall gases may have permeated the wood framing, causing cross-contamination that can result in the wood continuing to produce a foul odor.

Tannenbaum said the wiring is of particular concern because of the risk of fire if it were to fail. Lennar intended to leave behind much of the wiring in the Tibbettses' home, saying that insulated wiring was not affected, only the exposed wires.

"Knowing how damaging these gases have been, how do you know that underneath the covering it hasn't deteriorated?" Tannenbaum said. "It may turn out to be OK, that would be great, but we think someone needs to at least look at it first to be sure."

Martyak, with the Consumer Product Safety Commission, said the risk of fire also would be at the heart of his agency's investigation into affected homes.

"The goal is to determine if there is a safety hazard, and when you have wiring potentially corroding, that will be a very important concern," he said.

Commission investigators will be in Florida for the next several weeks gathering information, Martyak said, declining to specify where they were, or to what counties or regions they would be traveling.

One of the largest concentrations to date of Chinese drywall has been found in Southwest Florida, but America's Watchdog, a national consumer advocacy group based in Washington, D.C., says its investigations have found defective Chinese drywall in Florida, Arizona, Colorado, Georgia, Louisiana, Maryland, Nevada, New Jersey, New Mexico, North and South Carolina, Virginia and Texas.

The Herald-Tribune reported on Feb. 1 that shipping records show at least 550 million pounds of Chinese drywall has been offloaded at U.S. ports since 2006 -- enough to build 60,000 average-size homes.

Other builders who used Chinese drywall, according to the builders themselves, customers and attorneys, include Taylor Morrison, WCI Communities, Meritage Homes, Ryland Homes, Standard Pacific Homes and Aubuchon Homes.

On Feb. 13, U.S. Sen. Bill Nelson, D-Fla., sent a letter to the Consumer Product Safety Commission and the EPA asking both agencies to jointly investigate whether the Chinese drywall is toxic, and to determine the extent of the damage potentially being caused to people's homes.

"The commission needs to work with the EPA and other agencies to quickly determine the extent of problems with this drywall, order necessary remediation and create new safety standards to keep this from happening again," Nelson said Monday in a statement.

Nelson's legislative counsel, Christopher Day, said commission investigators are putting together a growing list of homes they will inspect during their first Florida visit.

Day said that given the scope of the potential problem, getting federal agencies involved opens the door to resources not available to state or local authorities.

"They have testing facilities that go beyond what is available at the state level," Day said.

One of the biggest challenges in testing the Chinese drywall to date has been the expense and the fact that only a few labs are capable of analyzing the tiny components causing the problem, which are measured in parts-per-billion or even parts-per-trillion.

The only testing released so far has been from labs hired by either a builder or a manufacturer. Day said that it seemed appropriate for an independent agency to become involved.

"Bringing in a completely neutral party we think would be useful," he said.

HOMEOWNERS AND CONDOMINIUM ASSOCIATIONS

A homeowners' or condominium association, after control of such association is obtained by homeowners or unit owners other than the developer, may institute, maintain, settle, or appeal actions or hearings in its name on behalf of all association members concerning matters of common interest to the members, including, but not limited to: (1) the common property, area, or elements; (2) the roof or structural components of a building, or other improvements (in the case of homeowners. associations, being specifically limited to those improvements for which the association is responsible); (3) mechanical, electrical, or plumbing elements serving a property or an improvement or building (in the case of homeowners. associations, being specifically limited to those elements for which the association is responsible); (4) representations of the developer pertaining to any existing or proposed commonly used facility; (5) protests of ad valorem taxes on commonly used facilities; and, in the case of homeowners' associations, (6) defense of actions in eminent domain or prosecution of inverse condemnation actions. If an association has the authority to maintain a class action under this rule, the association may be joined in an action as representative of that class with reference to litigation and disputes involving the matters for which the association could bring a class action under this rule. Nothing herein limits any statutory or common law right of any individual homeowner or unit owner, or class of such owners, to bring any action that may otherwise be available. An action under this rule shall not be subject to the requirements of rule 1.220.

Unfortunately, what the Florida Supreme Court did in providing automatic class action standing for homeowner associations was not coupled with the Florida Legislature, as it had done long ago for condominium associations (F.S. 718.203), inserting developer and contractor warranties of fitness and merchantability into F.S. Chapter 720 (homeowner associations). As a result, even though the procedure to get into court as a class has been made significantly easier for member of homeowner associations, identifying sustainable causes of action for securing compensation remains a challenge.