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Letter to Society of Toxicology

Letter to Society of Toxicology

Thursday, June 28, 2007

July 18, 2006

Dr. James A. Popp
President, Society of Toxicology
1821 Michael Faraday Dr., Suite 300
Reston, VA 20190

Dear Dr. Popp:

The Environmental Working Group (EWG) is a non-profit public health watchdog organization. We are writing to alert you that a current Society of Toxicology (SOT) member, Dr. Dennis Paustenbach, has committed a serious violation of the Society's Code of Ethics, and to strongly urge the Society to censure Dr. Paustenbach or take other decisive and appropriate disciplinary action. The Society must make clear that it will not tolerate unethical activity by its members, or risk seriously damaging its credibility.

Paustenbach's highly unethical conduct was recently confirmed by the editorial board of the Journal of Occupational and Environmental Medicine (JOEM), which in its July issue is retracting an influential journal article purporting to rebut the association between oral exposure to chromium in tap water and cancer. Paustenbach was directly involved in the design, writing and review of this paper, which failed to disclose the fact that PG&E, a major chromium polluter and Paustenbach client at the time, paid for the study.

This is a clear violation of the Society's ethical standards regarding disclosure of funding sources and conflicts of interest. What's worse is that by concealing the funding source, Paustenbach was able to use this study to weaken public health protections for chromium, a strategy that would not have been possible had the client that paid for the study been properly disclosed. Paustenbach's calculated deception was designed to benefit a client at the expense of millions of people with chromium contaminated tap water. It was not an isolated incident, but was the ultimate goal of a multi-year plan directed by Paustenbach to protect the financial interests of PG&E, with virtually no regard to the integrity of the science or the impact on public health. It is a plain violation of a second SOT principle that members "conduct their work with objectivity and themselves with integrity. Being honest and truthful in reporting and communicating their research."

In order to preserve the integrity of SOT as an organization with high ethical standards, we urge you to investigate the matter, and to censure Dr. Paustenbach.

As you know, SOT's Code of Ethics reads:

The Society of Toxicology is dedicated to developing and communicating knowledge to improve the health and safety of living beings and to protect the environment upon which we depend. To attain this objective, each Member must maintain high ethical standards, recognize a duty to share this knowledge with the public, and be a thoughtful advocate for human, animal, and environmental health. To this purpose, this code requires a personal commitment. [emphasis added]

The Code also lays out eight specific ethical standards that SOT requires its members to abide by. As described below, in the attached documents, and in a front-page Wall Street Journal article, Dr. Paustenbach has clearly violated two of these important standards.1 Specifically, Paustenbach has failed to abide by the Society's requirements that its members:

  • Conduct their work with objectivity and themselves with integrity. Being honest and truthful in reporting and communicating their research.
  • Abstain from professional judgments influenced by undisclosed conflict of interest, disclose any material conflicts of interest, and avoid situations that imply a conflict of interest.

In June, the prestigious Journal of Occupational and Environmental Medicine (JOEM) announced it would retract a 1997 study that had appeared to be written solely by two Chinese scientists, JianDong Zhang and ShuKun Li, with no conflicts of interest. In reality, the paper was largely written by Paustenbach's firm, ChemRisk, while under contract with the major chromium polluter Pacific Gas & Electric (PG&E).2 The retraction was specifically for hiding PG&E's financial sponsorship of the paper as well as ChemRisk's intellectual input.

The notice of retraction, which will be published in the July issue of JOEM, reads:

"It has been brought to our attention that an article published in JOEM in the April 1997 issue by Zhang and Li failed to meet the journal's published editorial policy in effect at that time. Specifically, financial and intellectual input to the paper by outside parties was not disclosed."3

Due to space considerations, we will not recount the full story of this deception here. Rather, we refer you to EWG's letter to JOEM editor Paul Brandt-Rauf, the December 23rd Wall Street Journal article, and the internal ChemRisk memos that we have attached. The remainder of this letter will be devoted to highlighting Paustenbach's role in Zhang and Li debacle, and how his activity directly violates SOT's Code of Ethics.

Paustenbach was CEO of ChemRisk when Pacific Gas & Electric hired the company to help defend against a major lawsuit brought by the small town of Hinkley, California. Local residents had sued PG&E, claiming that the utility was responsible for contaminating the town's drinking water with hexavalent chromium which, in turn, had caused many serious health problems in the community, including cancer. PG&E was in the process of losing the suit, which would eventually cost them $333 million and form the basis of the major Hollywood film Erin Brokovich, when Paustenbach, along with another ChemRisk scientist and the PG&E lawyers, hatched a plan to "follow up" on Zhang's 1987 study of chromium and cancer in China.4

Zhang's 1987 study was important in several ways: (1) the judges presiding over the negotiations told PG&E's lawyers that the study would be influential in their decision as to whether chromium-6 was harmful to human health; (2) the Agency for Toxic Substances and Disease Registry (ATSDR) had cited it as evidence that hexavalent chromium might be an oral carcinogen; and (3) as a ChemRisk scientist has explained in a court deposition, the study is "really the only epidemiology treatment that's out there in the literature of a groundwater contamination plume and its potential cancer effects in a population."5

What would become the 1997 Zhang and Li study was actually the second step in a two-step process for ChemRisk to essentially make Zhang's 1987 findings go away. An internal company memo shows that Paustenbach was expected to edit a report for PG&E that would form the "foundation of a number of trial exhibits that summarize the absence of the association between cancer and groundwater exposure to Cr+6 in JinZhou, China."6 A "subset of the material in this report, the memo explains, would then be used to write an article for a peer-reviewed journal where Dr. Zhang would be listed as first author.

This latter study was submitted to JOEM, appearing as if the paper was written entirely by the two listed authors, JianDong Zhang and ShuKun Li, updating a previously published 1987 analysis. Nowhere in the paper will you find any note of ChemRisk's involvement, or the names of any of the firm's employees. Nor will you find the name of Pacific Gas and Electric company, or any note that this "reanalysis" was done to defend the company in litigation.7 This explicitly violated the journal's editorial policy that required authors to disclose funding sources and potential conflicts of interest. [Apparently in a hurry to publish, ChemRisk also submitted the paper to both JOEM and the Archives of Environmental Health, despite the fact that this violated both journals' policies against simultaneous submissions.8]

When JOEM ultimately accepted the paper, ChemRisk sent a memo to the PG&E attorneys (copying Paustenbach) informing them of the firm's success. The memo, titled "Acceptance of China Paper," read:

We are pleased to inform you that the short communication regarding clarification of Dr. Zhang's previous work on cancer mortality in a Chinese population exposed to Cr(VI) in water was accepted with no revisions in the Journal of Occupations and Environmental Medicine. Dr. Zhang's previous paper (which is cited by ATSDR) states that total cancer and stomach cancer mortality was significantly elevated in populations living along the Cr(VI)-contaminated groundwater plume. This short communication clarifies that the cancer death rates (both total and stomach cancers) "were not correlated with the degree of exposure to Cr+6 and that 'neither stomach nor lung cancer indicated a positive association with Cr+6 concentration in well water.'" You will be receiving a copy of the accepted paper for your files by mail. If you have any questions regarding this paper, please call Brent Kerger at [phone number9].

This memo clearly indicates the true purpose of ChemRisk's work: to support PG&E's litigation defense without alerting the scientific community about either company's involvement. Or more to the point, hiding the sponsorship of the 1997 Zhang and Li paper was not merely an oversight, but was a critical component in an overall strategy, engineered by Paustenbach, to make it appear as though chromium does not cause cancer through ingestion, the route of greatest concern to his client.

Since ChemRisk's deception has been exposed, Paustenbach has attempted an Enron-style defense, claiming that as CEO he had only "very limited involvement" in the "collaboration" between ChemRisk and Dr. Zhang.10 Yet Paustenbach has admitted that he spent time "peer-reviewing" the 1997 paper before ChemRisk submitted it to JOEM.11

Given Paustenbach's involvement in the beginning, middle, and end stages of the Zhang/PG&E scheme, his Enron-style defense clearly fails to hold water. And it is particularly weak for the specific ethics violation cited by the JOEM in their retraction: ChemRisk's hiding its involvement and the source of funding. These are the aspects of the study with which Paustenbach was undeniably and directly involved.

Moreover, Paustenbach's hiding the source of funding for this work had a profound and calculated effect on the way the study has been received by health officials and regulators nationwide. ATSDR, for example, noted the findings of the 1997 study when the agency revised its toxicological profile for chromium in 2000.12 And the Environmental Protection Agency cited the 1997 study in its decision to renew the registration for a chromium-containing wood preservative.13 It is doubtful that the study would have been viewed in the same light, by health officials or by peer-reviewers at the JOEM, if it had been honestly disclosed as funded by PG&E and mostly authored by ChemRisk scientists, as opposed to the way it was presented—as a re-analysis conducted solely by the original author of his definitive work on chromium in drinking water and cancer.

Paustenbach continued to misrepresent the 1997 Zhang and Li study after it was published. On at least two occasions Paustenbach used the study as a critical piece of evidence to lobby for weaker chromium standards on behalf of industry, while hiding the fact that the study had been bankrolled by ChemRisk clients with enormous chromium financial liability.14 Paustenbach surely knew how tactically important concealing the funder of the study would be. After all, his client, PG&E, was in the process of losing the famous Erin Brockovich case and was on the hook for another multi-hundred-million-dollar verdict when Paustenbach and ChemRisk came to the rescue, at least temporarily, with this paper.

Ultimately, there can be no doubt that Dr. Paustenbach has failed to conduct himself "with integrity," has failed to be "honest and truthful in reporting and communicating" his research, has hidden clear "material conflicts of interest," and has failed to "avoid situations that imply a conflict of interest."

In short, Paustenbach has clearly violated SOT's Code of Ethics, both in word and in spirit.

The ethical misconduct we describe here is serious, and must be treated accordingly. SOT must act to reprimand Paustenbach for his unethical behavior if the scientific community is to continue to believe that SOT stands for integrity in science. We assert that such blatant violations of the Society's Code of Ethics should not be tolerated.


Richard Wiles
Sr. Vice President
Cc: Scott W. Burchiel, Membership Committee Liaison for SOT Council


[1] Waldman, P. 2006. Second Opinion. Study Tied Pollutant to Cancer; Then Consultants Got Hold of It. Wall Street Journal. December 23, 2005.

[2] Waldman, P. 2006. Publication to Retract an Influential Water Study. Wall Street Journal. June 2, 2006.

[3] Brandt-Rauf, P. 2006. Notice of Retraction. Available at

[4] Deposition of Brent Kerger. Volume 1. Page 89. December 4, 2002.

[5] Deposition of Brent Kerger. Volume 1. Pages 89 and 165. December 4, 2002.

[6] Memo from Bill Butler to Brent Kerger. August 7, 1995. Bates stamps: WB-0117 to WB-0122. Available at:

[7] Zhang, JinDong and ShuKun Li. 1997. Cancer mortality in a Chinese population exposed to hexavalent chromium in water. JOEM 39(4):315-319.

[8] Fax from Tony Ye to Gwen Corbett. January 24, 1996. Bates stamps TY-0529 to TY-0530. Also, Ye Deposition 1, page 68, line 17.

[9] Memo from Gwen Corbett to Greg Read et al. June 5, 1996. Re: Acceptance of China Paper. Bates stamp: BRP 0329. Available at:

[10] Paustenbach, D. 2006. Letter to the Editor. Wall Street Journal. Jan 21, 2006.

[11] Paustenbach, D. 2006. Letter to the Editor. Wall Street Journal. Jan 21, 2006.

[12] Agency for Toxic Substances and Disease Registry. 2000. Toxicological Profile for Chromium. US Department for Health and Human Services. September 2000. Available at:

[13] US Environmental Protection Agency. 2001. Inorganic Chromium - Report of the Hazard Identification Assessment Review Committee. Available at:

[14] Letter from Dennis Paustenbach to George Alexeeff. July 17, 2000. Available at: Also: Hearing of the California Senate Health and Human Services Committee. 2003. Possible Interference in the Scientific Review of Chromium VI Toxicity. February 23, 2003. Los Angeles, CA. Transcript available at:

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