Building Health Sciences, Inc. (BHS) provides a comprehensive, medically-focused, single source solution to Indoor Environmental and Air Quality issues that adversely affect building occupants as a result of building or material failures. We integrate medical and scientific principles with building diagnostic and investigative activities. We have been watching the evolution of the Chinese drywall crisis. To date the focus appears to be on the manufacturing, distribution and adverse effects of the Chinese drywall on homeowners and their residence. Our physicians have been following the issues of human health effects of the off gassing Chinese drywall. Even in the presence of noxious odors which may cause irritant symptoms in certain individuals, to date, no levels of sulfur-containing gases have been measured at or above any health-based regulatory standards.
Chinese drywall was introduced to the U.S. as a result of the housing boom and the aftermath of Hurricane Katrina, when the demand for drywall outstripped the supply and forced the importation of foreign-made drywall. An analysis of shipping records by the Sarasota Herald-Tribune has confirmed that since 2006, at least 550 million pounds of drywall from China, enough to build more than 60,000 average-sized homes, was imported. At the Port of New Orleans alone, enough Chinese drywall entered to build 6,500 homes. One south Florida building supply company reported that it had imported more than ten million square feet of the Chinese drywall between 2004 and 2005.
Builders facing issues relating to drywall from China include Miami’s Lennar Corporation, Taylor Morrison, WCI Communities, Meritage, Tousa Homes, Ryland Homes, Standard Pacific and Aubuchon Homes. South Kendall Construction Corporation was named in a recent suit. In January 2009, Lennar Homes moved residents out of a dozen homes it had built so that they could replace the Chinese drywall installed by its subcontractors and repair/replace damaged fixtures, plumbing, electrical wiring and air conditioning systems.
Initially, Indoor Environmental and Air Quality complaints were reported in a few southwest Florida homes. Complaints spread across Florida and into other states, including Virginia, Louisiana, Mississippi and Texas. Complaints involved detection of noxious sulfurous odors, which is exacerbated with heat and humidity. Potential health concerns reported included insomnia, nosebleeds, headaches and breathing difficulties. Additionally, the emissions from the Chinese drywall are causing corrosion of metals and damage to copper-containing electronic equipment, wires, pipes and air conditioning systems. Homeowners have reported corroded air conditioner coils, requiring replacement of the air conditioner, sometimes twice or more per year.
At the same time that property damages are being investigated, health concerns have not received sufficient scrutiny to draw any firm conclusions. The foundation of the BHS philosophy is that when health concerns are the driver of an incident, the solution must be health-driven as well. Thus, simultaneous assessment of the interrelationship between the occupants' health and building science is required; click here for our article on this topic. Currently, more information is required before a determination can be made on the potential impact of Chinese drywall on occupants' health beyond the odors, damage to equipment, building materials and asset value. Further investigation is proceeding under the guidance of the Florida Department of Health (FDOH).
Builders, health inspectors, state regulators and legislators, U.S. congressmen, at least two federal agencies, as well as law firms are now involved. Class action and individual lawsuits have been filed on behalf of homeowners against builders, suppliers and manufacturers. The primary Chinese drywall manufacturer named is Knauf Plasterboard Tianjin Co. Ltd., (Knauf) although other Chinese drywall manufacturers are also suspected of producing defective drywall, including Taishan Gypsum.
Complaints submitted to the Florida Department of Health (FDOH) prompted Senator Bill Nelson (D-FL) to request the Consumer Products Safety Council (CPSC) and the Environmental Protection Agency (EPA) to investigate. Joseph Martyk, CPSC spokesman, indicated that the commission would focus on whether the sulfur-based gases emitted form the drywall pose a safety hazard. If one is found, further sales of specific drywall products could be halted. Currently, the CPSC has no safety standards for drywall, nor is it aware of any federal standards for drywall. Nelson has, therefore, directed the CPSC to promulgate drywall safety standards to avoid future such problems. In March, according to the Wall Street Journal, the CPSC sent four additional staffers to Florida from its compliance, toxicology and electrical engineering departments. They joined four field investigators in assessing homes in Florida. Samples taken during their investigations will be tested.
Florida's Governor Crist has officially requested that the Environmental Protection Agency (EPA) develop and implement chemical testing strategies in affected homes. In the same letter, he also has asked The Centers for Disease Control (CDC) and the Agency for Toxic Substances and Disease Registry (ATSDR) evaluate the health hazards possibly associated with the corrosive gases emitted by the Chinese made drywall. To view Governor Crist’s letter, click here.
Testing for Knauf
Knauf became aware of odor complaints about its Chinese drywall in 2006 and retained The Center for Toxicology and Environmental Health, L.L.C. (CTEH®) to do testing. CTEH performed both bulk testing of the drywall, as well as, air quality testing in several homes. CTEH determined that the root cause of the drywall smell was from iron disulfide, a naturally-occurring mineral in the Chinese gypsum mine. Knauf says it stopped using the mine in late 2006. Knauf claims that, based on CTEH’s testing of their drywall, there are no health concerns. Click here for letter from Knauf dated November 29, 2006 and the CTEH Summary of Air Sampling results.
Chemically, the iron disulfide mineral (i.e., pyrite) is the source of the sulfur-containing compounds emitted from the drywall. In the process of manufacturing the drywall, the iron disulfide is heated, causing the emitted sulfur to oxidize, forming highly-soluble sulfur dioxide which remains in the drywall. When the drywall emits sulfur dioxide under conditions of high heat and humidity, it reacts with water vapor and ultimately forms highly-corrosive sulfuric acid which attacks metals such as copper and silver included in many home fixtures and systems.
ENVIRON International Testing Results
ENVIRON International, Corporation (Environ) in October 2008, briefed the FDOH regarding its investigation of sulfur compound emissions from imported gypsum wallboard and related health considerations. For a copy of this briefing memorandum click here. The investigation was directed by a toxicologist and a certified industrial hygienist. They concluded:
- the release of sulfur-containing gases was demonstrated selectively from wallboard imported from China;
- corrosion of certain components found in affected homes could be re-created in a test chamber by exposing otherwise unaffected copper to the Chinese wallboard;
- room air from over thirty homes in southwest Florida was analyzed for sulfur-containing gases and the following was noted:
- carbon disulfide was detected in approximately half of the sampled homes, with typical concentrations of approximately 5 ppb;
- all samples of carbon disulfide were below 15 ppb.
- the minimal risk level (MRL) for carbon disulfide is 300 ppb, for chronic exposure (365 days and longer)
- Hydrogen sulfide was never found at levels higher than the coincident outdoor level.
It is important to remember that exposure to a level above the MRL does not mean that adverse health effects will occur. In this case, the MRL is at least 20 times higher than the observed level of carbon disulfide.
When ENVIRON conducted follow up investigations on HVAC system failures in southwest Florida, an unusual rate of copper heat exchange coil corrosion with loss of integrity was found. The corrosion caused the refrigerant gas to escape and the HVAC units to freeze-up. Materials testing of the observable black residue on the HVAC coils confirmed this to be sulfur-based. Subsequent chamber testing with an unaffected copper sample demonstrated that wallboard from China emitted carbon disulfide, carbonyl sulfide and hydrogen sulfide which resulted in corrosion chemically similar to the copper corrosion seen in the affected homes.
Testing for the Florida Department of Health
The FDOH, through their State Toxicologist, Dr. David Krause, collected and analyzed drywall samples from a small number of homes in south Florida. Unified Engineering, Inc., a private laboratory, conducted testing on four samples of drywall. Two of the samples came from drywall manufactured in China, one sample was unidentified, and one sample was from US-based National Gypsum and was installed in the same home as a Chinese brand. Click here for a copy of the Unified Engineering report released by the FDOH.
Testing indicated that the Chinese drywall contained significant amounts of organic material, ranging from five to fifteen percent. Identifying the organic material will take further testing. The tests demonstrated that heat and humidity play a critical role in the emission of sulfur and corrosive gases from the drywall, according to Dr. Krause. This may indicate why the problem first became apparent in south Florida.
Their preliminary analysis of their chamber tests confirmed the presence of several chemicals capable of causing corrosion in the complaint homes. Unified Engineering reported that hydrogen sulfide, carbonyl sulfide and carbon disulfide were all detected at levels between 100 and 1000 ppb. Trace levels of strontium sulfate were also found in the drywall suspected to be from China. In moist air, strontium sulfate reacts with the water vapor to form hydrogen sulfide, a gas which has the odor of rotten eggs and which is corrosive.
However, Dr. Krause pointed out that the initial testing was designed only to determine what chemicals were being released into the air as a means of guiding further investigation. Therefore, the levels found in such chamber testing are not necessarily indicative of levels that would be found in a home. Dilution by the greater volume of air inside a home would naturally results in lower concentrations. Dr. Krause warned that the measurements performed thus far were not exposure measurements, but rather chamber experiments.
Previous testing has "not identified any concentrations of chemicals that are in homes that are at a level…that would pose a specific health risk," said Dr. Krause. Further investigation into possible health effects is planned by the FDOH. Thus far, Dr. Krause has noted, available data has not identified levels of corrosive gases exceeding those recognized as posing a health risk. The FDOH is continuing to seek data from all parties regarding occupant exposures to chemicals, as well as secondary hazards that may arise from corroded building materials.
Environmental Protection Agency (EPA)
In order to determine how much of each chemical emitted by the drywall is actually present in affected homes, the US EPA will conduct the next phase of testing. As noted above, Governor Crist of Florida has asked the CDC and the ATSDR to evaluate the health hazards possible associated with the corrosive gases emitted by the Chinese made drywall. Thus, until the EPA concludes its evaluation on the health effects associated with the emissions from Chinese drywall, any reported health effects will have to be considered inconclusive. BHS will continue to monitor the current investigations into the health impact of drywall manufactured in China.
