Environmental Health & Engineering Inc. (EH&E), a leading Massachusetts-based engineering consulting firm, has completed a major indoor air quality study for the U.S. government which found a strong association between the presence of Chinese drywall, low level concentrations of hydrogen sulfide, and corrosion of metals in homes.
The drywall issue has affected thousands of homes in the United States for more than two years.
The five-month EH&E study included 51 homes in five southern states; 41 homes where property owners had reported corrosion of wiring or piping, and ten similar homes about which no complaints had been filed. The following findings were presented by John F. McCarthy, Sc.D., C.I.H., president of EH&E, in a Congressional briefing at the U.S. Capital on Monday, November 23, 2009:
- In homes with suspect drywall, the following conditions were determined:
- High rates of sulfur-based corrosion on copper and silver test coupons.
- Visible corrosion of copper wires in electrical outlets.
- Low level concentrations of hydrogen sulfide gas.
- Low ventilation rates.
- Associations of corrosion with hydrogen sulfide concentrations in air, temperature and humidity.
- A reliable real-time method of "fingerprinting" suspect drywall using state-of-the-art inspection equipment was developed and validated.
The EH&E presentation to Congress and report prepared for the Consumer Product Safety Commission are available for review at this website: http://www.eheinc.com/cpsc_drywall.htm.
EH&E was selected for the project based on its high level of building science expertise and field experience in characterizing complex indoor environments and in homes, schools, and offices. The company had been the prime contractor for indoor air quality to the U.S. Environmental Protection Agency, and two of its principals, John D. Spengler, Ph.D., and John F. McCarthy, Sc.D., C.I.H., edited what is considered the most comprehensive guide available today on indoor air quality, the "Indoor Air Quality Handbook".