The Proposed Ban on the Use of the Flame Retardant Deca-BDE contained in HB 1488/SB 5515 is Not Scientifically Supportable
February 2006
One of Seattle's most majestic sights is the view of Mount Rainier on a clear day. That view has become the center of the The key legislative proposal contained in HB 1488/SB 5515 is to ban the use of the flame retardant Deca-BDE as soon as a viable environmentally friendly alternative becomes commercially available. The rationale behind this legislation is embodied in the Washington State Department of Ecology/Washington State Department of Health (WDOE/WDOH) report "Washington State Polybrominated Diphenl Ether (PBDE) Chemical Action Plan (CAP)" In addition to banning Deca-BDE the bills call for a ban of two other chemically similar brominated fire retardants, Penta-BDE and Octa-BDE neither of which are currently in production. It should be noted that no other State, Federal or International governmental entities has called for a similar ban of Deca-BDE without further study. Most of these entities have concluded that, based on current scientific information, Deca-BDE does not pose a human or environmental threat. The CAP on the other hand attempts to underpin its policy recommendation using two key dubious assumptions:
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Deca-BDE when released to the environment will degrade to more toxic species of PBDE i.e. Penta-BDE and Octa-BDE.
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The release of Deca-BDE will increase in the future which in turn may cause human exposures of potential concern.
Although the 276 page CAP reflects a very significant level of staff effort by WDOE/WDOH, it fails to validate these two key assumptions. Further the risk assessment aspects of the CAP are not consistent with standard protocols for estimating human health risks. The CAP actually contains all of the data and supporting information to do so but for some unexplained reason such protocols were not followed.
There were also too many tenuous analogies cited in the CAP trying to couple possible PBDE health risks with those associated with PCBs and Dioxin/Furans. If we apply standard scientific methods, the risk estimates show that there is no parallel in the current exposure health risks due to PBDE exposures and PCB/Dioxin/Furan exposures in Washington or the United States in general.
What are the current exposure risks of Deca BDE and its potential degradation products?
The CAP speculates that Deca-BDE when released to the environment will degrade in part to Penta- and Octa-BDE, which are "more toxic." Although there is a lengthy discussion of the available scientific literature on the subject, there is little evidence presented by the CAP authors indicating that the formation of Penta- and Octa-BDEs are quantifiable end products of viable Deca-BDE degradation pathways.
Additionally the CAP does not differentiate between the cancer and non-cancer risks of the stated "more toxic degradation products." Based on current scientific evidence, Penta- and Octa-BDE are not carcinogenic to humans while Deca-BDE is the only one classified as a "potential human carcinogen." This is a Class C rating which is the lowest potential cancer causing category. This rating also carries with it the caveat that there is not sufficient animal test data upon which to develop a cancer risk factor for human exposure.
This constraint did not preclude WDOE from developing a Cancer Slope Factor (CSF) for use in their cost benefit analysis. The CSF that they used was more toxic from a cancer causing perspective than Benzene, a known human carcinogen. This is not a plausible comparison and dramatically overestimates any potential cancer impacts of Deca-BDE.
What are the current Deca-BDE and degradation product health risks?
The cancer risk of Deca-BDE exposure can be compared to current PCB and Dioxin/Furan exposures to the general population. The paper by Schecter et al (2005)(2) presents comparative blood level data for all three classes of organic compounds of concern. If the rather suspect Cancer Slope Factor for Deca-BDE derived by WDOE/WDOH in the CAP is compared to the cancer risk posed by the measured blood levels of PCBs and Dioxin/Furans. The relative cancer risk of these latter compounds is over 37,000 times the Deca-BDE cancer risk. This is a critical point because the CAP continuously tries to draw toxicity comparisons between PBDE and Dioxin/Furan/PCB toxicity.
The dominant non-cancer risk associated with PBDEs is that associated with Penta-BDE according to the CAP health benefits analysis. The population most at risk is nursing infants who are exposed to mother's milk containing trace levels of Penta-BDE. This risk to the in State infant population is based on the mothers breast milk survey data taken by Northwest Environmental Watch. The daily intake of Penta-BDE by nursing infants can be compared to the current scientifically accepted Reference Dose (RfD). The Reference Dose is the scientifically determined dosage level assumed to have no adverse health effects. The ratio of the daily intake of any toxic chemical to the RfD defines the Hazard Index (HI). A HI of 1.0 or less is considered to be a safe exposure free of any health risk.
The Hazard Index for the exposure of nursing infants based on the average of the NW Environmental Watch survey data for Penta-BDE in breast milk is 0.002, or a factor 500 times lower than the level deemed safe. The HI for the highest measured breast milk level in the NW is 0.01 or 100 times lower than the safe level.
There is new scientific research that shows effects in rodents at levels lower than those used in setting the current RfD. However even if a revised RfD emerges from the detailed U.S. EPA IRIS review process is 100 times lower than the current RfD, it is unlikely the revised H.I. will be greater than 1.0.
For these reasons the CAP is scientifically flawed when it attempts to present a cost benefit analysis containing health benefits estimates based on human exposures risk levels which are essentially non existent. According to U.S. EPA an individual cancer risk of one in a million is insignificant yet WDOE/WDOH estimated the cancer death rate among Washington's population when the individual cancer risk using their questionable Cancer Slope Factor was two orders of magnitude lower than one in a million.
This same flaw applies to WDOE's non-cancer health benefits estimates where by definition there are no calculable health risks when the HI is at or below 1.0 for any toxic compound.
The other major assumption, which WDOE/WDOH relied upon to underpin the policy option to ban Deca-BDE, was the potential for significant future growth in the statewide use/importation of products containing Deca-BDE. It was assumed that such growth would translate to the increased release of Deca-BDE and its degradation products to the environment. The CAP proffers the argument that such growth will increase exposure levels to those that may be of health concern. This hypothesis is not supported by any reasoned analysis of the CAP.
The CAP policy recommendation to ban the use of Deca-BDE in Washington is not supported by a sound scientific analysis of the data and supporting information contained in the CAP. The recommendation seems to follow the application of the "precautionary principle" where policy decisions are made on the basis of uncertainty versus perceived risk. The uncertainty factor is emphasized over and over in the text of the CAP to underpin the WDOE/WDOH position. When the available data, contained in the CAP, is applied in a focused scientifically correct manner, the implied health risks associated with present exposures to PBDEs in the State are non-existent.
Rather than banning these effective flame retardants, the Washington State Department of Ecology and the Washington State Department of Health should continue to monitor the issue consistent with the approach taken by other governmental agencies.
Dr Jones has over 40 years experience in the environmental engineering field. He has professional experience in government, the private sector and academia. He is a retired US Public Health Service Officer and has served as a Senior Advisor at the President's Council on Environmental Quality under both the Ford and Carter Administrations. Nothing in this document should be construed as any attempt to aid or hinder any legislation before any legislation body. Washington Policy Center is a nonpartisan, nonprofit 501(c)(3) research and education organization. Contact Washington Policy Center at 206-937-9691 or online at washingtonpolicy.org.