Presented at The UMass Soils Conference October, 2010

Transcription

1 Presented at The UMass Soils Conference October, 2010 PCBs in Building Caulk Health Hazard or Regulatory Over Reaction Presented by James Okun Principal O Reilly, Talbot & Okun Associates, Inc. 1

2 O Reilly, Talbot, and Okun [ A S S O C I A T E S ] ENGINEERING Health Hazard or Regulatory Over Reaction? Environmental Safety Health Geotechnical Engineering Consultants 2

3 1. Based on the best data we have, PCBs are not highly toxic to people. 2. Asbestos, lead, radon and a number of other chemicals/materials commonly found in the environment cause more harm and are demonstrably more toxic to people than are PCBs. 3. The resources required to eliminate PCBs from in-place building materials is significantly out of proportion with the human health risk they actually pose. 3

4 A critical evaluation of actual human data shows that PCBs at concentrations that Americans are likely to be exposed to in buildings do not pose a significant risk of adverse health effects. Claims that PCBs are a serious health risk to school children and the public at large are based on BS Bad Science. 4

5 The mischaracterization of PCBs is mostly due to their environmental persistence and their structural similarity to chlorinated pesticides, dioxins and polychlorinated dibenzofurans. The initial misjudgment of PCB toxicity was greatly exacerbated by the mistaken interpretation that Yusho and Yu-Cheng Disease were caused by PCBs. The PCB regulations (40 CFR 761) are complex and have a punitive undertone. 5

6 BS Degree Chemistry, MS Toxicology from MIT. Post grad research on PCBs in the environment at the University of Hawaii. EPA Region 1 s first PCB coordinator. EPA s first project manager on New Bedford Harbor CERCLA site. Environmental consultant for 28 years. 6

7 First I am not saying that PCBs are non-toxic. What I am saying is that their human toxicity is insufficient to warrant the heightened level of concern about PCBs in building materials. Second In toxicology there is a saying that the dose makes the poison ; a small dose produces little or no effect. There is no evidence that the very small dose of PCBs a person receives from exposure to building materials will result in a toxic effect. 7

8 Here is what I plan to cover: We will briefly review the Yusho and Yu- Cheng mass poisonings and their cause; Then we will do a little comparison of the adverse health effects from PCBs contrasted with the effects of other common toxic agents; and Finally we will take a look at the claims about PCBs causing human cancer. 8

9 The Yusho rice-bran oil mass poisoning in Japan (1968) and the Yu-Cheng rice-bran oil mass poisoning in Taiwan (1979) were nearly identical in their circumstances. In each case a leak from a PCB heat-exchanger contaminated rice-bran oil with PCBs. Hundreds of people were made terribly ill and experienced horrible permanent skin deformities. These two incidents formed the basis of the public perception regarding PCB toxicity. 9

10 Subsequent testing of the rice-bran oil found not only PCBs, but high concentrations of Poly- Chlorinated Quaterphenyls (PCQs) and Polychlorinated Dibenzo-Furans (PCDFs). Chemical analysis showed that only a third of the organo-chlorine in the rice oil was PCB related; the rest was linked to PCB breakdown products. PCQs and PCDFs are absent or nearly absent in unused PCBs, but are readily formed when PCBs are used for extended periods at high temperatures (> 250 o C). 10

11 PCDFs are between 10,000 and 100,000 times more toxic than PCBs. To this day almost nothing is known about the toxicity of PCQs. Japanese and American researchers have concluded that all of the toxicity from Yusho and Yu-Cheng can be explained by the presence of 2,3,7,8 TCDF and 2,3,4,7,8 PCDF concentrations in the rice oil. While present at much higher concentrations than the PCDFs, PCBs appear to not have significantly contributed to the toxic effects. 11

12 Symptoms (toxic effects) arising from occupational exposures to unused and unheated PCBs reverse after exposures cease. Symptoms from Yusho and Yu-Cheng poisonings did not reverse following the end of exposure. While some toxic effects are similar, Yusho and Yu- Cheng teach us that PCDF toxicity is different and far more serious than PCB toxicity. 12

13 US made PCBs contained little or no PCDF at the time of their manufacture. Under normal building use, the temperature of building caulk, paint and floor finishes do not approach the level needed to form PCDFs. PCB congener distribution in indoor air samples generally show > 85% mono, di-, and tri-chloro PCBs, the least toxic of the many PCB congeners. PCDFs are approximately times less volatile than PCBs (for the same degree of chlorination) 13

14 6) Yusho and Yu-Cheng Disease Hundreds of technical papers describing the chemistry and toxicology of Yusho and Yu- Cheng Disease. Of particular note is the excellent survey article contained in Encyclopedia of Environmental Science and Engineering ; Pfafflin, J. R. and Ziegler, E. N. 5 th Edition 14

15 Asbestos May well be the most toxic material humans have ever widely used. Still responsible for over 10,000 deaths in the US every year, and that number is still going up. Asbestos disease is generally irreversible. Fortunately, regulations require schools to make asbestos safe. Despite many exposures, there have been few if any reported deaths arising from PCB exposures when other contaminants were not also present (PCDFs, PCDDs or PCQs). Disease from PCB exposure is generally reversible. 15

16 This year in Nigeria over 300 children died as a result of lead poisoning when their drinking water supply was contaminated with waste water from gold mining operations. In the US it is estimated that 1% of children have blood lead levels high enough to reduce their ability to learn, in Massachusetts the number is 0.69% (2007 CDC data). What s the number of children killed or whose learning was impaired by PCBs? Zero. 16

17 EPA estimates that between 8,000 and 45,000 lung cancer deaths per year are caused by radon gas that seeps into indoor air; the risk is 10 times higher for smokers. Radon is the number one cause of lung cancer among non-smokers. Lung cancer is a leading cause of cancer deaths in the US. There is no required national program to test radon in schools or to abate radon if it is found in schools. What is the number of lung cancer deaths caused by PCBs? Zero. 17

18 The point of this comparison is to provide some perspective on the difference between big toxic risks and little toxic risks. Asbestos, lead and radon kill and cause irreversible injuries to hundreds of thousands of people each year and the scientific literature is full of unambiguous studies and statistics proving it. No such scientific literature exists proving that PCBs are seriously toxic to people. When PCB toxicity has occurred in people, it has been the result of a dose thousands of times greater than may occur to children in schools. 18

19 In some animals (rats and other rodents), high doses of PCBs do cause cancer. Possible problem for politicians, TV and radio hosts. However, when you look at the scientific literature describing tens of thousands of human occupational PCB exposures, there is no evidence of a causal link between exposure to PCBs and any type of cancer. The non-scientific and regulatory literature is full of alarming warnings about PCBs and cancer, but the scientific studies do not support those claims. 19

20 Q. So how can it be that EPA says that PCBs pose cancer risk? A. Well actually even EPA and ATSDR do not say that PCBs cause cancer in humans. They say that based on animal studies (using rats) it may be a human carcinogen with the liver as the target organ. In Monkeys, closer to most of us than rats, there are cellular changes in the liver following PCB dosing, but this effect reverses and doesn t result in liver cancer. 20

21 Studies show statistically significant developmental effects to infants whose mothers ate Great Lakes game fish. These were fish taken from areas known to be contaminated. In addition to PCBs, the fish contained an assortment of metals (like methyl-mercury and lead), PAHs and other contaminants. No clear link to PCBs as the causative agent, particularly given the known adverse developmental effects of the metals. 21

22 1. Good scientists are skeptical scientists. Good scientists challenge conventionally accepted science and say prove that to me. I have been looking for the proof that PCBs are dangerous enough to justify taking them out of building materials; I am not finding it 2. Most important, Good Science is reproducible science. When a scientist reports new findings a second (and a third) scientist must be able to reproduce those results; if this can t be done, what you have is BS. Regulatory decisions should not be based on BS. 22

23 PCBs are very persistent oil-like chemicals used in a variety of building materials between about 1950 and PCBs are much less toxic than asbestos, lead or radon. Human studies show PCB induced disease (caused by much higher exposures than occur in schools) to be reversible. At the concentrations found in schools, PCBs have not been shown to cause disease or increased health risks. 23