What are the consequences of Toxic Chinese Drywall and how can I avoid it?

The recent state of the “toxic drywall” debacle  is a bit of a mixed blessing here.  The mass majority of the toxic drywall came from just a few manufacturers in China that used mined gypsum as these raw materials for the wallboard, and was produce in 2005, 2006 and 2007.  The vast majority of this “toxic drywall” was largely characterized by the strong evolution of sulfur dioxide, which gave it a rotten egg smell and was the major cause of the corrosion that destroyed the homes electrical systems, air conditioners and other metal appliances and fixtures.  While there have been  many complaints about the negative health effects of people living in homes with Chinese drywall,  the real physiological effects of the “toxic drywall” have not been conclusive, especially considering that the major sulfur based components are not present in concentrations high enough to be the root cause of all of the symptoms people were complaining about.  It is quite possible that, while the corrosion of the metal is a real effect of sulfur dioxide exposure, the plethora of the health related claims are more a psychosomatic reaction and less of a biochemical or physiological effect of sulfur dioxide exposure.

To give you some perspective, this is a dose response chart showing that with increasing concentrations of sulfur dioxide, you get different physiological effects.

* 0.0047 ppm is the recognition threshold, the concentration at which 50% of humans can detect the characteristic odor of hydrogen sulfide [1], normally described as resembling “a rotten egg”.
* 10-20 ppm is the borderline concentration for eye irritation.
* 50-100 ppm leads to eye damage.
* At 150-250 ppm the olfactory nerve is paralyzed after a few inhalations, and the sense of smell disappears, often together with awareness of danger,
* 320-530 ppm leads to pulmonary edema with the possibility of death.
* 530-1000 ppm causes strong stimulation of the central nervous system and rapid breathing, leading to loss of breathing;
o 800 ppm is the lethal concentration for 50% of humans for 5 minutes exposure(LC50).
* Concentrations over 1000 ppm cause immediate collapse with loss of breathing, even after inhalation of a single breath.

According to an testing agency, Environ, who were paid by one of the main home builders involved in the building and now litigation with the Chinese drywall, over 30 homes with Chinese drywall were tested for sulfur dioxide levels.   The concentrations of sulfur dioxide in these homes averaged 5 ppb(parts per billion, 1 thousand fold less than ppm or parts per million, which is what is listed in the biological affects chart above).  Because Lennar, the builder and defendant in many of these lawsuits, paid for these tests, we should view the results with some skepticism, but these levels are 100 to 1000 times less than the levels we can expect to cause typical sulfur dioxide exposure symptoms and other health related effects that homeowners are claiming is cause by the Chinese drywall.

The real problems that eventually penetrated 37 states, but was largely localized to just five states: Florida, Virginia, Mississippi, Louisiana and Alabama, have largely been mitigated for new construction.  Most of these manufacturers have “miraculously” stopped manufacturing this toxic drywall, though they claim to not know the cause of the toxicity in the first place and have done nothing to change the manufacturing process, and so can still claim that they didn’t do anything wrong.

The Consumer Product Safety Commission(CPSC) identified the ten top manufacturers of the toxic drywall, listed here:

  1. Knauf Plasterboard (Tianjin) Co. Ltd.: (year of manufacture 2005) China
  2. Taian Taishan Plasterboard Co. Ltd.: (2006) China
  3. Shandong Taihe Dongxin Co.: (2005) China
  4. Knauf Plasterboard (Tianjin) Co. Ltd.: (2006) China
  5. Taian Taishan Plasterboard Co. Ltd.: (2006) China
  6. Taian Taishan Plasterboard Co. Ltd.: (2006) China
  7. Shandong Chenxiang GBM Co. Ltd. (C&K Gypsum Board): (2006) China
  8. Beijing New Building Materials (BNBM): (2009) China
  9. Taian Taishan Plasterboard Co. Ltd.: (2009) China
  10. Shandong Taihe Dongxin Co.: (2009) China

Notice that there are no North American Manufacturers here.  Also notice the dates after the names.  These dates identify the year that the toxic drywall was produced by these plants and subsequent analysis has shown that many of the worst offenders are now producing drywall with sulfur dioxide levels at or near North American manufacturers levels.  No reasoning can be given for the sudden change in the makeup of the Chinese drywall.

If you feel like saving a few bucks by buying the Chinese drywall and taking your chances, that is up to you but this seems like a great time to help reinforce our economy, reduce our trade deficits and get a safer product by buying (North) American drywall.   To date, there have been no tests showing any North American manufactured drywall has posed any life risk or property damage, though there have been over 2000 complaints from homeowners in the US that claim, despite the lack of evidence, that they are the victims of homes built with toxic US made drywall.  Their claims have been tested by the CPSC but no evidence of toxicity and very low levels of sulfur dioxide were found in all North American manufactured drywall. The CPSC has deemed North American drywall safe.  We recommend Pabco and USB.  The latter has the greatest recycled content of any wallboard manufacturer in North America.

This entry was posted in Green Building Questions, Indoor Air Quality. Bookmark the permalink.

One Response to What are the consequences of Toxic Chinese Drywall and how can I avoid it?

  1. Rachel says:

    We’re fortunate to have choices for building suppliers and manufacturers, and in the home it’s definitely worth a little extra cost to go with materials you know to be safe and non-toxic. After all, you’re exposed to them every day.

    Thanks for the toxicity facts, and for the referral to ‘clean’ drywall companies.

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