WASHINGTON, D.C. – The U.S. Consumer Product Safety Commission (CPSC) and the U.S. Department of Housing and Urban Development (HUD) today released updated remediation guidance for homeowners with problem drywall. The guidance calls for the replacement of all: problem drywall; smoke and carbon monoxide (CO) alarms; electrical distribution components, including receptacles, switches and circuit breakers, but not necessarily wiring; and fusible-type fire sprinkler heads.
The updated remediation guidance is based on studies just completed by the National Institute of Standards and Technology (NIST) on potential long term corrosion effects of problem drywall on select gas components, fire sprinkler heads and smoke alarms.

CPSC and HUD staffs believe these final studies that resulted in an update of the remediation guidance, along with previously-issued identification guidance, will enable homeowners to comprehensively remediate those homes containing problem drywall with potentially lower costs than by following the previous remediation guidance.

Key Findings

The key finding is that none of the studies performed at NIST on smoke alarms, fire sprinkler heads, or gas service piping found corrosion associated with problem drywall that provided evidence of a substantial product safety hazard, as defined by the Consumer Product Safety Act. Corrosion of gas service piping was uniform and minimal compared to the thickness of pipes. Some smoke alarms and fire sprinkler heads showed small changes in performance due to accelerated corrosion, but these changes were generally within accepted industry standards.

As a result, CPSC and HUD no longer recommend the removal of gas service piping in homes with problem drywall. This change may reduce the cost of remediation for many homes. In addition, the agencies no longer recommend that glass bulb fire sprinkler heads be replaced in homes. However, the agencies recommend that both glass bulb sprinkler heads and gas distribution piping in affected homes be inspected and tested as part of the remediation to make sure they are working properly; any test failures should be corrected according to all applicable building codes.

The agencies do recommend the replacement of all fusible-type fire sprinkler heads, because one fusible-type sprinkler head sample that had been exposed to accelerated corrosion did not activate when tested. The agencies note that this type of sprinkler head is generally found in commercial, rather than residential, applications and that the sole failure could not be causally linked to the problem drywall.

In addition, CPSC staff continues to recommend that homeowners replace smoke alarms and carbon monoxide alarms as part of remediation.

Exhaustive Investigation

CPSC’s investigation into problem drywall to help affected homeowners began in early 2009 and involved significant agency resources. CPSC’s investigation of problem drywall has been driven by sound science and has involved HUD, the U.S. Centers for Disease Control and Prevention (CDC) and the U.S. Environmental Protection Agency (EPA) as members of the Federal Interagency Task Force on Problem Drywall.

CPSC and HUD met with deeply-impacted homeowners, responded to correspondence, and kept members of Congress informed about our progress during this time period.

CPSC developed contracts to research and test problem drywall, visited Chinese mines and manufacturers, hosted a public website to keep the public informed about new developments, and devoted thousands of staff hours and millions of dollars to these activities.

As part of the effort to determine if there were any health or safety effects associated with problem drywall, the agency contracted with several highly-respected technical organizations, including Lawrence Berkeley National Laboratory (LBNL), Environmental Health & Engineering Inc. (EH&E), Sandia National Laboratories (SNL), NIST, and the U.S. Geological Survey (USGS).

LBNL used specially-built chambers to measure chemical emissions from drywall samples. In the second phase of its work, which is being released today, LBNL evaluated the effects of different temperature and humidity conditions, as well as the effects of time and coatings of paint or plaster, on the emissions. A prior LBNL study found considerably higher hydrogen sulfide emission rates from some, but not all, Chinese drywall samples compared to North American samples. The current LBNL study found that increases in temperature and humidity corresponded with increased emission rates of the most reactive sulfur gases, that emissions were significantly reduced over time (compared with its prior testing), and that coating the problem drywall samples did not result in differences in emissions compared to uncoated samples.

EH&E conducted CPSC’s 51-home study on emissions and corrosion in problem drywall homes. The studies identified elevated levels of hydrogen sulfide in problem drywall homes. The studies also showed a strong association between the presence of hydrogen sulfide and metal corrosion in the problem drywall homes.

SNL exposed smoke alarms, electrical components, gas piping, and sprinkler heads to concentrated levels of gases representative of problem drywall emissions, to simulate decades of exposure. SNL analyzed the effects of corrosion on the electrical components and found no degradation in performance and no acute safety events during testing.

NIST analyzed the type and depth of corrosion resulting from the simulated aging, as well as other samples taken from homes with problem drywall, and evaluated whether the corrosion would impact the proper functioning of smoke alarms, gas distribution piping, and fire sprinklers.

Another study being released today, that was conducted by the USGS, found no evidence of microbiological activity or a microbiological source of sulfur-gas emissions from gypsum rock or problem drywall, including samples taken from affected homes.

As part of the investigation, CPSC requested that CDC consider undertaking a comprehensive study of any possible long-term health effects. In February 2011, CDC indicated that the best scientific evidence available at that time did not support undertaking a long-term health study.

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