"When we add end-of-life with accidental landfill fires and backyard burning, the additional risk of dioxin emissions puts PVC consistently among the worst materials for human health impacts..." USGBC Technical Science Advisory Committee (TSAC) final report.
The verdict is in. On February 26, 2007, the Technical Science Advisory Committee of the U.S. Green Building Council (USGBC) released the results of its long awaited assessment of the health and environmental impacts of polyvinyl chloride plastic (PVC) building materials. In recommending against a LEED credit for PVC elimination, the TSAC delivered a data rich defense of its rationale that such a credit would not necessarily ensure that LEED users would select an overall environmentally superior material. This is not a new dilemma. Selecting a LEED-accredited low VOC product, for example, has long been recognized as critically important for indoor health, but does not guarantee that the alternative is better for other environmental attributes.
Far more significant is the TSAC finding that when human health impacts are appropriately considered, PVC was consistently worse than alternatives. Equally important, the damning data were associated with PVC production and end-of-life, phases of the material life cycle that are not unique to the materials or product types examined by TSAC. As a result, the TSAC has highlighted concerns that apply to other PVC building materials such as wall coverings or membrane roofs.
The TSAC report runs over 200 pages, and looks at PVC and two to three alternative materials in four product types. They summarized their impact findings in three categories: Cancer, Total Human Health and Environment and provided a low, average and high estimate for each category. Predictably, the results varied depending upon which estimates were used. It is interesting to note, that even using the low end estimates, PVC is rarely superior in any product type. Low end estimates are not, of course, protective of human health. Taking a Precautionary Principle approach to examine the TSAC data using the average to high estimates of impact for all materials makes the following clear:
On TSAC's Cancer ranking, PVC is consistently the absolute worst for each of the four product types studied.
On TSAC's Total Human Health ranking, PVC consistently comes out either tied for worst or absolute worst.
On TSAC's Environmental ranking, PVC's performance is mixed — still absolute worst in the case of flooring - both VCT and sheet vinyl - but better than one alternative and roughly equal to the alternatives in the other three cases. Within the specific Environment subcategories performance is scattered with only cork flooring consistently outperforming every other alternative in its category in all environment indicators.
So it comes down to this. If you screen out PVC from your materials choices, you always get better human health, but you may (or may not) trade off some or all of the "other" environmental attributes, depending upon which material you pick.
Much work lies ahead to develop more useful screening tools, such as HBN's own Pharos Project, to help the designer quickly select materials and push the market on multiple environmental fronts.
In the meantime, the transition away from PVC can continue with another indicator in place that human health will be a winner.
The Vinyl Institute is attempting to discredit the TSAC's findings through press releases that downplay the importance of landfill fires in the life cycle of PVC. For background and analysis of the VI's assertions, see the TSAC article in the PharosWiki at http://www.pharosproject.net/wiki/index.php?title=USGBC_TSAC_PVC#Landfill_fires [link no longer available]
For more information on the health effects of dioxin and relationship of dioxin to building materials, including PVC, see the dioxin article in the PharosWiki at http://www.pharosproject.net/wiki/index.php?title=Dioxin [link no longer available]
The USGBC's "Assessment of the Technical Basis for a PVC Related Materials Credit for LEED" dated February 2007 can be found on the USGBC's web site at http://www.usgbc.org/DisplayPage.aspx?CMSPageID=1633. The human health impacts quote is from the Summary of Findings section of the main report on p. 88, line 24.
 The product areas and materials TSAC studied are: windows (PVC, aluminum and wood), pipe (PVC, cast iron and ABS), siding (PVC, aluminum and fiber cement) and resilient floor (VCT, sheet vinyl, linoleum and cork)
 Total human health includes Cancer plus more effects including global climate change, particulates, mercury.
 TSAC looked at acidification, eutrophication, smog, ozone depletion, global climate change, fossil fuel depletion, and ecotoxicity, then normalized the scores to one ranking.
 PVC consistently ranks worst for TSAC's Cancer ranking, even if low end estimates are used.
 Specifically it ranked better on environment than cast iron pipes, aluminum siding and aluminum windows and not significantly different from ABS pipes, wood windows, wood siding and fiber cement siding.