USGS Research Hits Home: Investigating Troublesome Household Wallboard

Marisa Lubeck: Welcome and thanks for listening to this episode of CoreCast. I am Marisa Lubeck. The U.S. Geological Survey has been contracted to study the yet unknown source of problematic hydrogen sulfide emissions coming from certain household wallboard, which is imported from China and used in some regions of the U.S. Today I am speaking with USGS chemist, Steve Wilson, who is working on this problem wallboard issue with the Consumer Product Safety Commission or CPSC. 



Steve, can you provide a general overview of the basic science here? What is this chemical coming from the wallboard? What is causing it and how is the USGS involved?



Steve Wilson: At the height of the housing boom in the years 2005 and 2006, coupled with Hurricanes Ivan and Katrina that hit Gulf coast, there became a shortage of domestic wallboard in this country, so suppliers needed to go outside this country to find other sources of wallboard. And one place they went to is China. So they begin to import Chinese wallboard into this country.

01:00

And what happened was, when certain Chinese drywall was installed in homes, especially along the Gulf and Atlantic coasts, homeowners found a strong odor beginning to emanate from that wallboard almost right away. That was later traced back to the presence of hydrogen sulfide coming from the wallboard. Hydrogen sulfide has a pretty strong rotten egg kind of smell which is very noticeable even at low concentrations.

 Hydrogen sulfide can attack exposed copper wiring such as in household electrical systems, which raised safety concerns. The CPSC has been the lead federal agency investigating problem drywall and has collected thousands of consumer reports of problem drywall.  The CPSC came to the USGS for their expertise in geochemistry and to help identify constituents in problem drywall. CPSC reported that there are a lot of gases coming out of wallboard. And a lot of those are pretty common. We have them in the household all the time, but hydrogen sulfide is very atypical. The question was where this comes from.

02:00

And that was one of the major things CPSC wanted us to do. It is to look at the chemical composition of the wallboard and the paper.



Marisa Lubeck: What kind of information does this research provide that is of use to the CPSC with this problem?



Steve Wilson: When the CPSC came to us, there were two major areas of information they wanted to get from us. The first was if we could identify what the source material was for the hydrogen sulfide coming out of the wallboard. Second was, could we identify a chemical fingerprint that would help the CPSC identify a problem wallboard. That way we can help develop standards to identify that this wallboard is a problem but maybe this one is not.



Marisa Lubeck: How is it that a chemist with the USGS would end up testing something like wallboard?



Steve Wilson: The USGS looks at gypsum which is a major component of wallboard that we use in this country domestically for a variety of industrial applications. Because of its truly broad range of interests, the USGS has had to develop capabilities to look at those types of samples and ask, "What's in this stuff?"

03:04

And as a chemist, that's one of the things that we do. We help each other to understand what is going on in a particular sample by identifying what the chemical composition is. 



Marisa Lubeck: Why did the CPSC enlist the help of the USGS? Why is your specific work the most appropriate for this project?



Steve Wilson: It turns out the CPSC and the USGS were kind of a natural fit for this because of the analytic capabilities we have here as well as the good geologic understanding of what is going into the formation of gypsum.



Marisa Lubeck: I understand that the USGS became involved relatively recently. What have you accomplished so far?



Steve  Wilson: Two major areas that CPSC wanted us to look at source material and the fingerprint, to supplement some work they have already completed in that endeavor.  We've gone ahead and looked at a variety of sample types that CPSC has provided us, from wallboard samples from China and also domestic samples. We looked at natural gypsum material from China as well as synthetic gypsum that's derived from the energy industry as a byproduct.  We asked, What's the chemical composition of all those different types of materials, and basically we found that we are already able to distinguish the chemical composition but we have not seen any definite source material present in the wallboard itself.

04:09

But we have been able to work out a way to fingerprint those problem wallboard samples from non-problem wallboard.



Marisa Lubeck: What has been the biggest challenge you have faced with this project and how did you overcome it? 



Steve Wilson: Whenever you start a new project that has high degree of visibility you have to kind of rush around and get everything in place to make sure the samples are processed correctly and we get the people lined up so that they know when samples come in the door and you do this, you do this, and you do that. So logistical issues became the biggest problem and we had to tweak some of our chemical analysis to optimize the analysis for some of these elements. There wasn't necessarily anything that was unusual for us, it's just a matter of focusing our attention to different items.



Marisa Lubeck: What remains to be done in terms of the fundamental science?

Steve Wilson: We're continuing to work with the CPSC in the form of analyzing additional samples from China and domestic sources. 

05:04

And we're going to begin to work with a colleague down in the Tallahassee office of USGS because one of the issues we thought was interesting was that because we did not see anything significant in terms of the sulfide minerals in the wallboard samples, we thought about  what other sources could there be? The techniques that we have at the USGS and Tallahassee office may allow us to do a more detailed, more tentative test for that type of work. So that's one of the biggest next steps, and then phase two work with the CPSC and we hope they will be able to identify the source or the reason for this particular problem.



Marisa Lubeck: Steve thanks for taking the time to speak with us today.



Steve Wilson: You’re Welcome.



Marisa Lubeck: This podcast is a product of the U.S. Geological Survey Department of the Interior. I am Marisa Lubeck. Thanks for listening.