Date: August 10, 2009
To: Joel Recht, PhD, Director, Laboratory Sciences Chemistry, U.S. Consumer Product Safety Commission Ana M. Viamonte Ros, MD, MPH, State Surgeon General of the Florida Department of Health
From: State and Federal Drywall Technical Evaluation Team (CPSC, EPA, CDC/ATSDR, FLDOH, LADHH, and VADOH) (see Appendix 3 for the names and affiliations of Team members)
Subject: Technical evaluation of “EPA’s analysis of Florida drywall samples1 and review of analytical results from the Florida Department of Health,” from the EPA’s National Air and Radiation Environmental Health Laboratory (NAREL). 7/31/09
Testing by federal and state agency radiation laboratories indicates that samples of imported and domestic drywall contain only background concentrations of naturally- occurring radionuclides that are typically found in soil-derived materials and used in common building materials. As a result of recent speculation by consultants, homeowners, and the media about imported drywall containing phosphogypsum2, the Florida Department of Health (FLDOH) Radiation Laboratory and the EPA National Air and Radiation Environmental Laboratory (NAREL) analyzed the same set of 21 drywall samples for radiological evidence of phosphogypsum contamination.
Based on the data from the two laboratories, the Technical Team concludes that there is no phosphogypsum contamination in the drywall samples tested. In particular, the levels of 226Ra found in these samples were generally more than a factor of 10 lower than those found in phosphogypsum (10 to 35 pCi/g), but comparable to levels found in other commonly used building materials including bricks and concrete. Seventeen of the 21 drywall samples analyzed were collected by the U.S. Consumer Product Safety Commission (CPSC) and four were collected by the FLDOH. Both agencies’ samples included imported and domestic drywall (Table 1).
1 The Technical Team notes that the drywall samples were from CPSC and FLDOH (CPSC samples were collected from multiple states).
2 Phosphogypsum is gypsum generated as a by-product of phosphate production and contains elevated levels of naturally occurring potassium, and thorium and uranium radionuclides and decay products.