New Chinese Drywall findings from CPSC studies
November 24, 2009 by admin
Filed under Toxic Injury
The CPSC has released findings from studies done on the Chinese Drywall problems.
The Studies
The 51 home study contracted by CPSC was done by Environmental Health &
Engineering (EH&E), an internationally known environmental testing firm based in
Massachusetts.
In addition, today two preliminary reports on corrosion safety issues are being released.
The Sandia National Laboratories’ (SNL) Materials and Engineering Center is studying
the long-term electrical safety hazards of conductor metal components. The National
Institute of Standards and Technology (NIST) is studying the corrosion effects on fire
safety components taken from complaint homes.
Findings
EH&E compared 41 “complaint” homes in five states selected from CPSC’s consumer
incident report database, with 10 noncomplaint homes built around the same time in the
same area as the complaint homes. Homes were sampled between July and September
2009.
The EH&E findings are that hydrogen sulfide gas is the essential component that causes
copper and silver sulfide corrosion found in the complaint homes. Other factors,
including air exchange rates, formaldehyde and other air contaminants contribute to the
reported problems.
In ways still to be determined, hydrogen sulfide gas is being created in homes built with
Chinese drywall. Earlier studies found large amounts of elemental sulfur in the Chinese
drywall. CPSC is investigating drywall from other sources that may mimic the problems
found with Chinese drywall. CPSC is meeting with drywall manufacturers and others
who are studying this issue to take their findings into consideration.
EH&E exposed copper and silver test strips, known as coupons, in homes for a period of
about two weeks. The coupons showed significantly higher rates of corrosion in
complaint homes than in the control homes. The dominant species of corrosion on the
coupons was copper sulfide and silver sulfide, as determined by additional laboratory
tests. Visual inspection and evaluation of ground wire corrosion also revealed
statistically significant greater ground wire corrosion in complaint homes compared to
non-complaint homes.
The EH&E study also found that by using hand-held x-ray fluorescence (XRF) and
Fourier Transform Infrared (FTIR) instruments, they were able to detect markers that
could identify Chinese-made dry wall at a sheet-by-sheet level.
While drywall-related corrosion is clearly evident, long term safety effects are still under
investigation. Like the EH&E study, initial reports available today from SNL and NIST
show copper and silver sulfide corrosion on samples of metal taken from homes with
problem drywall. These ongoing investigations will help the CPSC identify the nexus of
problem drywall and long term safety issues.
In addition, the EH&E study found elevated formaldehyde readings in both the control
and complaint homes. This is typical for new, more air-tight homes due to items such as
cabinets and carpets which emit formaldehyde. Both formaldehyde and hydrogen sulfide
are known irritants at sufficiently high levels. The concentrations measured in this study
were below those levels. Investigators believe that the additive or synergistic effects of
these and other compounds in the subject homes could cause irritant effects evident in the
homes.
In addition, the chinese drywall lawsuits are scheduled to begin in New Orleans on January 25, 2010.
