Drywall imported from China during the height of the housing boom and hurricane reconstruction period several years ago has been reported to be the cause of unpleasant odors and the corrosion of metal building products and household items. The focal point for these problems has been Florida; however, homeowners in some other regions have reportedly experienced similar concerns.
Problem (Tainted) Drywall
A strong association has been made between the corrosion of metal building components and household items and the presence of certain drywall products used in the construction or renovation of some homes. To date, the majority of homes affected by this condition are located in Florida and other southern states, from Virginia to the Gulf Coast states; however, instances of similar problems have been identified in over 30 other states.
What is occurring to cause these problems?
Investigative reports have found that the outgassing (vapor release) of sulfur elements from some brands of drywall, in particular, certain drywall products imported from China, are the primary cause of the metal corrosion.
When sulfur elements mix with moisture and other naturally occurring elements in the air, acidic compounds form. It is these acidic compounds that cause the corrosion of metal building components, particularly those made of copper. A warm, humid environment tends to increase the outgassing rates and corrosion potential. The sulfur emissions from the defective or “tainted” drywall can also create unpleasant odors.
This sulfur emissions problem has primarily been associated with imported drywall; however, in some cases other products are suspect. In addition, there are other materials and conditions in a home that can cause odors and/or corrosion of building materials, possible leading to the false identification of the existence of tainted drywall.
Where was the imported drywall used?
Shipping reports indicate that more than 50% of all suspect imported drywall was delivered to ports in Florida and used in Florida. But records indicate that the imported drywall was also shipped to other states, including but not limited to: Louisiana, Texas, Mississippi, the Carolinas, California, Arizona, New Mexico, Ohio, Nevada, Colorado, Maryland, Virginia New Jersey and Washington. There have also been some reports of it being shipped to British Columbia.
What homes are at the greatest risk of having tainted drywall?
The homes most at risk include:
- Homes and condominiums built between 2003 and 2007 (although some studies expand the window of concern from 2001 to at least 2008).
- Homes in areas where work on renovations or additions, or hurricane reconstruction, occurred during this time period.
- Homes with unexplained mechanical or electrical component malfunctions.
- Homes where metal components, such as air conditioner coils or exposed copper electrical wires, have turned black or corroded, and/or have required replacement, even though relatively new.
- Homes with an unpleasant odor (a sulfur or rotten egg-type smell), especially if the odors appears to be more prominent in warm, humid weather.
- Homes where occupants have experienced respiratory irritations or headaches that seem to diminish when they leave the home.
Each of these conditions can be caused by a number of other factors; although, if several or all exist in a particular home, the risk of the presence of tainted drywall is increased.
While the greatest amount of imported drywall was used in Florida, its warm, humid climate has also contributed to a fairly rapid manifestation of the symptoms associated with tainted drywall products.
Are there any serious health effects?
While there also have been claims of respiratory ailments and other health issues by occupants of homes with odors and corrosion problems that may be associated with tainted drywall, the data collected to date has not clearly identified levels of corrosive gasses in those homes that exceed levels recognized as posing a serious risk to health. Investigations by the Consumer Product Safety Commission (CPSC) and other federal and state agencies are ongoing.
How can I tell if there is imported drywall in my home?
While the presence of certain odors and the corrosion of building components may point to the presence of tainted drywall, to confirm these problems are related to the drywall generally requires documenting that the drywall was installed between 2001 and 2008 and metal corrosion exists, along with collaborating investigations and tests.
The manufacturer of drywall can't easily be identified by its appearance. In some cases there may be labeling on the back side of the drywall; indicating it came from China or was made by a manufacturer whose product has been identified as being defective. Some manufacturers, however, did not apply any markings, or applied inconsistent or improper markings. It is also possible that a mix of imported and domestic drywall, or tainted and standard drywall, was used in any particular house. So random sampling for drywall labels may not be a conclusive indication of potential concerns.
What testing methods are available?
A threshold inspection may indicate possible concerns, however, sampling and further evaluation by professional assessors and testing labs is required to confirm that conditions in a home are caused by tainted drywall − or to rule out potential concerns. Recommended collaborating tests include exposing metal test strips to the air in the home for several weeks; measuring the amount of sulfur in the blackened surfaces of components; analyzing the chemical makeup of the gypsum in the drywall from bulk samples; measuring the level of sulfur elements emitted from samples of drywall placed in test chambers; and monitoring the corrosion rate of metal placed in a test chamber along with suspect drywall samples taken from a home. Bulk sampling involves cutting out pieces of the drywall, securing it in an airtight cover, and bringing it to a lab for analysis.
Several factors can affect test results including the amount of sulfur elements present in the drywall, as well as temperature and humidity levels at the time of sampling. Consequently, while positive test results may point to a potential concern, a negative test result doesn't automatically rule out the presence of tainted drywall or other products that may contribute to problems in a home.
Can I bring a sample to a lab myself?
Some companies are advertising test kits that homeowners can use to test for sulfur content or emissions; however, the ability of these kits to identify tainted drywall or the symptoms, is questionable. Some labs also accept homeowner samples; however, any evaluation for tainted drywall is best done by a qualified specialist in conjunction with testing by a certified lab.
Beware of unqualified companies offering drywall testing or mitigation services. Also, realize that other factors in a home can cause conditions similar to those that have been associated with tainted drywall.
How can the problem be corrected?
Indoor air quality control methods, such as maintaining a cool, low-humidity environment may temporarily affect the odors and slow the rate of corrosion; however, the only current remediation method appears to be removal of the tainted drywall, and damaged components, and any associated residue, and replacement.
Note: Investigations of the effects of tainted drywall on building components, as well as the health of occupants is ongoing. Review information on tainted drywall at the federal Drywall Information Center and the Florida Department of Health websites. For information on local issues and recommendations, contact your local building and health departments. Also check for updated information regularly as investigations and legal matters proceed.