How PG&E's Scientists-For-Hire Reversed Findings of Cancer Study
How PG&E's Scientists-For-Hire Reversed Findings of Cancer Study
A consulting firm hired by Pacific Gas & Electric Co. (PG&E) to fight the "Erin Brockovich" lawsuit distorted data from a Chinese study to plant an article in a scientific journal reversing the study's original conclusion that linked an industrial chemical to stomach cancer, according to documents obtained by Environmental Working Group (EWG).
The chemical was hexavalent chromium, or chromium-6 (commonly abbreviated Cr+6 or Cr VI). In the Brockovich lawsuit, residents of Hinkley, Calif., sued PG&E for dumping chromium-6 in their tap water — the basis for the Julia Roberts film released in 2000. The deception occurred in 1995-97, and before the article's publication PG&E paid $333 million to settle the case, but the point is hardly moot.
The question of whether chromium-6 in drinking water causes cancer is at the center of an ongoing lawsuit against PG&E by residents of another small California town, again represented by Brockovich's law firm. Scientists and regulators — including the U.S. Environmental Protection Agency — have cited the fraudulent article in research and in setting safety standards. And the consulting firm that produced and placed the article continues to do risk assessments and other projects for corporate and government clients, including the Department of Energy and the Centers for Disease Control.
The Wall Street Journal reported today that the San Francisco-based consultants, ChemRisk, "conceived, drafted, edited and submitted to medical journals" a "clarification" of the Chinese study, according to documents filed in another chromium lawsuit against PG&E. They did so despite a letter of objection from the Chinese scientist who led the original study, calling their reversal of his findings an "inappropriate inference."
Through the state Public Records Act, EWG has obtained from the California Office of Health Hazard Assessment (OEHHA) the documents that tell the story. It's a story of science for sale, and of how far some industrial polluters will go to manipulate science for their own interest.
Medical Journal and CDC Urged to Take Action
The fraudulent "study" was published in the Journal of Occupational and Environmental Medicine, a peer-reviewed publication of the American College of Occupational and Environmental Medicine. EWG has written the journal's editors urging them to set the record straight and bar the scientists who were involved in the deception from its pages.
"The scientific community must be notified that a paper circulating in the published literature is fraudulent, the paper must be retracted, and those responsible for the incident must be appropriately disciplined," EWG's letter to Journal of Occupational and Environmental Medicine says.
EWG has also written to the Centers for Disease Control (CDC), which recently renewed ChemRisk's multi-million dollar contract for a key project at the Los Alamos National Laboratory, urging the agency to take prompt action against the company.
"ChemRisk's current ... contract must be cancelled and the firm barred from seeking future contracts from the CDC or other government agencies," says EWG's letter to CDC informing them of ChemRisk's ethic violations.
In 1987, Drs. JianDong Zhang and XiLin Li published a study in a Chinese medical journal that found "significant excess of overall cancer mortality" in five rural villages in Liao-Ning province, where the groundwater was contaminated with chromium-6 from a chromium ore processing facility.  But ten years later, in April 1997, the Journal of Occupational and Environmental Medicine (JOEM) published an article under the byline of Zhang and ShuKun Li (the reason for the different name of the second author is unclear) that reversed that conclusion, stating that the data from Liao-Ning province "do not indicate an association of cancer mortality with exposure to Cr+6 contaminated groundwater." 
To all appearances, the 1997 JOEM article was the result of a researcher conducting a more thorough analysis of the original data and revising the findings accordingly, not an uncommon practice in science. But nothing could be further from the truth.
The truth is told in court documents and depositions filed in another lawsuit against PG&E over chromium-6 contamination of drinking water, brought by residents of Kettleman City, Calif., which is scheduled to come trial in early 2006. Kettleman City and Hinkley are the sites of PG&E stations that pump natural gas from a Texas pipeline to California customers. Chromium-6 was used to cool the natural gas, then dumped in unlined ponds which leached the contaminant into groundwater.
ChemRisk 'Study' Concealed Cancer Link
The documents show that ChemRisk employees — with the knowledge of PG&E's attorneys — conducted their own analysis of Zhang and Li's data, deliberately ignoring statistics on cancer in the province that pointed to an association with chromium-6. They then wrote and submitted the article for publication without disclosing that they worked for ChemRisk or that PG&E had paid for the new "study." Zhang, now deceased, was a paid consultant to the project, but the documents suggest his biggest contribution was providing his original data. Nowhere in the published article are the names of the ChemRisk employees who worked on it, or any indication that the paper was part of PG&E's legal defense strategy.
Documents and depositions indicate that most of the work was done by ChemRisk scientists Bill Butler and Tony Ye with help from several other employees. The cover letters and other correspondence with JOEM have not surfaced, but presumably identical correspondence with another journal show how ChemRisk was able to avoid having its connection to the article known. Although Ye typed the cover letter at work, it was printed on plain paper rather than company letterhead; the return address was Ye's home, not his employers' offices. (Before the article was published, Butler and Ye left to form their own company, Environmental Risk Associates, which continued to bill PG&E for work on the article.)
At the time, ChemRisk was a division of McLaren/Hart Environmental Engineering, an international consulting firm that went bankrupt in 2001. Today — under different ownership but the same executive officer — ChemRisk is based in San Francisco with offices in Boston, Pittsburgh, Houston and Boulder, Colo., "providing state-of-the-art toxicology, industrial hygiene, epidemiology, and risk assessment services to organizations that confront public health, occupational health, and environmental challenges." 
Among its many corporate and government clients, ChemRisk holds a contract from the Department of Energy and the Centers for Disease Control (CDC). Under this contract, believed to be for 5 years and $5 million †1, ChemRisk will analyze hundreds of thousands of documents accounting for all chemical and radioactive materials released from Los Alamos National Laboratory in six decades of nuclear weapons work. 
The founder and president of ChemRisk is Dennis Paustenbach, who was CEO of McLaren/Hart when it owned ChemRisk.  Paustenbach has made a career out of consulting and testifying on behalf of dozens of big polluters including PG&E, ExxonMobil and Dow Chemical. [6,7] Independent scientists blasted his 2002 appointment to a CDC committee that assesses the health effects of chemicals as part of a Bush Administration pattern of packing environmental panels with industry-friendly experts.  The Newark Star-Ledger, in an investigation of Paustenbach's role in weakening chromium standards in New Jersey, said he "rarely met a chemical he didn't like." 
Getting to the bottom of ChemRisk's misdeeds is not just an intriguing scientific detective story. Zhang and Li's original work remains the only study of people ingesting chromium-6 in their drinking water.  The JOEM article reversing its findings was cited by the U.S. Environmental Protection Agency in a 2001 assessment of whether chromium-6 should be allowed in a wood preservative, and by the Agency for Toxic Substances and Disease Registry in a 2000 report that said elevated cancer rates in Liao-Ning "probably reflect lifestyle or environmental factors rather than exposure to chromium." [10, 11]
Most significantly, the article was cited prominently by a scientific panel whose 2001 report forced California health officials to revise a recommendation for how much chromium-6 should be allowed in drinking water.  The Office of Environmental Health Hazard Assessment (OEHHA) had recommended a level based on the assumption that chromium-6 in drinking water causes stomach cancer, but the panel pointed to the JOEM article as evidence to the contrary. Not coincidentally, Dennis Paustenbach was a member of the panel, although he resigned after his ties to chromium polluters were exposed.  (OEHHA's revised recommendation for chromium-6 in drinking water is scheduled to be released this fall and will not rely on the discredited 1997 "study". )
†1 CDC would not release the terms of the contract without a Freedom of Information Act request which could not be completed under deadline. This figure comes from a New Mexico source close to the project.
Debate Over Chromium Standards
Chromium is a naturally occurring metal used in steel manufacturing, leather tanning, welding, and the production of dyes, pigments and alloys. It is also often used to plate metal surfaces, is a major component of the pesticides used in pressure-treated lumber, and was also a common anti-corrosive agent used in cooling towers until the federal government banned the practice in 1990.  But not all chromium is created equal.
Trivalent chromium, or chromium-3, is a necessary nutrient naturally present in many foods and added to many vitamins as a dietary supplement. The other major type, chromium-6, is produced mainly through industrial processes, enters living cells much more readily than trivalent chromium, and is known to cause a variety of acute health effects when ingested at high levels, including vomiting, convulsions, ulcers, kidney and liver damage. [15,16]
There is no question that chromium-6 is a dangerous chemical. The International Agency for Research on Cancer, the EPA, and the National Toxicology Program all say chromium-6 causes cancer when inhaled. [16,17,18] Last year the Occupational Safety and Health Administration (OSHA) announced it would lower its safety standard for inhaled hexavalent chromium by a factor of more than 50 after it became clear that the current standard was too high to protect workers. 
How dangerous chromium is in drinking water is more controversial. Scientists agree that much chromium-6 is converted to the safer chromium-3 by stomach acid. But how quickly, and how much? Once inside a cell, chromium-6 is extremely toxic. If cells take up chromium-6 before it converts to chromium-3, it has the potential to cause many health problems, including cancer. Recent research has shown that orally ingested chromium-6 penetrates to tissues and organs throughout the body. 
In 1977, California set a safety standard of 50 parts per billion (ppb) for total chromium (which includes all chromium compounds) in drinking water. The EPA subsequently adopted the same standard, then in 1991 weakened it to 100 ppb. California disagreed with the looser standard and retained its original 50 ppb limit, the same guideline used by the World Health Organization. [21,22]
But in the late 1990s the California Environmental Protection Agency (Cal-EPA) realized that even this level was still too high to adequately protect human health and began to re-examine the standard. [14,21] In 2001 the state Legislature passed a law requiring the Department of Health Services (DHS) to set a drinking water standard just for chromium-6.  The standard is more than a year overdue, but when it is set California will be the first state to specifically regulate chromium-6 in drinking water.
To set a standard, the first step was for OEHHA to determine the level of chromium-6 in water that would be safe for all Californians to ingest over the course of a lifetime with no adverse effects. To establish this Public Health Goal (PHG), OEHHA reviewed all available toxicity information, including the 1997 JOEM article. The paper was important because it was the only drinking water study in the scientific literature to report on specific types of cancer.  Second, the panel of scientists assigned by the University of California — including Paustenbach — to provide OEHHA guidance had given the study great emphasis.  OEHHA wasn't looking for a scientific fraud or a polluter's coverup — but that's exactly what it found.
Chromium Pollution and Scientific Integrity
In 1959 the JinZhou Alloy Plant, located in a rural area in Liao-Ning province in northeastern China, began processing chromium ore. Its poor waste disposal practices quickly led to massive chromium-6 pollution. The plant not only released chromium-laced wastewater into a neighboring dry riverbed that cut through nearby villages, it also dumped thousands of tons of solid waste onto bare ground around the plant site. Rainwater percolating through the waste piles leached chromium-6 into the groundwater. 
When investigators from the JinZhou Health and Anti-Epidemic Station began sampling well water from nearby villages in early 1965, they discovered that almost a third of the wells in the two villages closest to the plant were contaminated with chromium-6. By the end of the year, the incidence of contamination had risen dramatically in these two villages, and sampling in three more distant villages revealed polluted drinking water and irrigation wells as well. By the 1970s, the contamination plume had spread to more distant villages.  The contamination wasn't contained until the early 1980s, when a concrete barrier was installed around the plant. 
Health surveys conducted from 1965 through 1974 found that residents in all five contaminated villages suffered from a variety of ailments associated with chromium-6 exposure: mouth ulcers, diarrhea, abdominal pain and vomiting. JianDong Zhang and XiLin Li, scientists assigned to the health station, published a series of articles in Chinese journals documenting the health problems.  Their work culminated in the 1987 paper in the Journal of Chinese Preventive Medicine that linked chromium-6 exposure to the higher rates of cancer found in the contaminated area.  This study has never been published in English, but the 1997 JOEM article summarized the earlier study's conclusion as "a significant excess of overall cancer mortality in five Cr+6 contaminated villages combined."  The JOEM article, published under the names of Zhang and ShuKun Li, comes to quite different conclusions. Its abstract reads:
This report is a clarification and further analysis of our previously published mortality study regarding groundwater contamination with hexavalent chromium (Cr+6) in the JinZhou area of China between 1965 and 1978. In our previous report, we stated that a significant excess of overall cancer mortality was observed (P = 0.04) in five Cr+6-contaminated villages combined. Further analysis revealed no clear statistical increase in cancer mortality in the three villages adjacent to the source of the contamination (P = 0.25), where 57% of the wells exceeded the European Community safe drinking water standard of 0.05 ppm Cr+6. These results do not indicate an association of cancer mortality with exposure to Cr+6-contaminated groundwater, but might reflect the influence of lifestyle or environmental factors not related to Cr+6. Further follow-up of this cohort is recommended. 
The 1997 study acknowledges that the five villages taken together still had high cancer rates, but reverses the 1987's study's conclusion that chromium-6 was to blame. The JOEM paper states that the villages closer to the chromium-6 plume had lower rates of stomach and lung cancer than those farther away, and that the cancer rates in the three villages closest to the source were not significantly higher than the surrounding province. The article also suggests that the Agency for Toxic Substances and Disease Registry should revise its assessment of the 1987 study in light of the new "findings":
"The absence of a dose-response relationship between cancer and Cr+6 clarifies a translation and interpretation of our previous publication made by the Agency for Toxic Substances and Disease Registry. Although Cr+6 contamination cannot be ruled out completely as the reason for the high cancer death rates in these villages, these results do not support such a relationship." 
It's a Small World
Fast forward to California in August 2001. OEHHA's draft safety level for chromium-6 in drinking water had been roundly criticized by the Paustenbach panel, and the agency had withdrawn its recommendation. [12,14]
OEHHA scientist Jay Beaumont was assigned to look further at the JOEM article repeatedly cited by the panel. In an email to his colleagues, after summarizing the two articles, Beaumont pointed out "several notable limitations and oddities in the Zhang and Li 1997 paper." 
Although actual chromium-6 concentrations were available for each of the villages, Beaumont noted, the authors chose to use distance from the industrial source as "a surrogate for exposure." The concentrations would be a better measure, yet Beaumont noted that the authors provided no reason for not using the actual levels, even though they were contained in a table included in the paper. He also noticed that the authors failed to explain how they calculated distance from the pollution source — an important detail since some of the villages are more than a kilometer in width. To top it all, the paper misused three epidemiologic terms.
Although OEHHA scientists still had little reason to doubt the article's overall veracity, they began digging deeper. As they looked more closely at the connection between chromium-6 and stomach cancer, their doubts grew. The JOEM article looked at stomach cancer death rates, but didn't compare them to rates in the province, as it did for rates of total cancer.  The article said this questionable choice was because stomach cancer rates weren't available for the province.  But that's not what Jay Beaumont found.
In an e-mail to OEHHA chief Joan Denton, he wrote: "I checked to see whether the rates should have been available, and in fact they were available from the same source from which the investigators obtained other rates. The age-adjusted stomach cancer mortality rate in the province was 20.9 per 100,000 per year, while the rate in the contaminated villages was 37.1." [25: Excerpt | Full document] Overall, OEHHA's analysis showed that stomach cancer rates in the contaminated villages were 87 percent higher than found in the surrounding province, and this finding was statistically significant. Beaumont wrote another OEHHA colleague: "I wouldn't call this 'negative'!" [26: Excerpt | Full document]
Confused, OEHHA tried to track the authors down. Beaumont found a Web page promoting Zhang's rather unorthodox theories on wearing "bio-ceramic" underwear to protect against breast and prostate cancer.  The Web site said Zhang was a consultant to McLaren/Hart, ChemRisk's parent company. The CEO of McLaren/Hart, of course, was the same Dennis Paustenbach who had made the JOEM article a central point in the scientific panel's critique of OEHHA.
Paustenbach, who holds a PhD in toxicology, testified for PG&E in the Hinkley case — earning fees of $300 an hour — and once soaked in a hot tub full of chromium-laced water to try to prove that it was harmless.  The ChemRisk Web site touts his work for the American Petroleum Institute, Chemical Manufacturers Association and the Formaldehyde Institute.  He is on the editorial board of the journal Regulatory Toxicology and Pharmacology, which 40 prominent scientists denounced in 2003 "as a convenient venue for the publication of industry research." 
The Newark Star-Ledger's investigation found that in the 1990s, three companies responsible for widespread chromium pollution hired Paustenbach to help them attack the state's strict cleanup standards. "When state scientists determined chromium caused skin rashes, Paustenbach's team argued the DEP [Department of Environmental Protection] was using the wrong testing method. When that argument failed to convince the department, Paustenbach and his team again did their own study and used the results to argue that the standard was too restrictive," reported the Star-Ledger.  Over a decade, Paustenbach's work helped save the companies an estimated $1 billion in cleanup costs by persuading the state to weaken its chromium standards from 10 parts per million in soil to more than 6,000 ppm. When the newspaper asked a former Clinton Administration environmental official about Paustenbach, he replied: "Ah, Dr. Evil." 
Even before he was named to the California chromium-6 review panel, Paustenbach and his work for chromium polluters was well known at OEHHA. In 2000, he'd written the agency to argue that the Public Health Goal should not be based on the assumption that chromium-6 in drinking water causes cancer. His letter cited the fraudulent 1997 ChemRisk paper, "the only epidemiological study of humans exposed to Cr(VI) through drinking water," as reporting "no excess in gastrointestinal cancers" even though levels were well above the California safety standard. [74: Excerpt | Full document]
So when Jay Beaumont found Zhang's Web page saying he was a consultant for McLaren/Hart, it wasn't hard to put two and two together. In an email to colleagues, he wrote:
"Thus the money to pay Dr. Zhang likely came from the industrial clients of McLaren/Hart who have a strong financial interest in the health effects evidence for Cr6. I don't know what Dr. Zhang was paid to do by McLaren/Hart, but republishing his study with different conclusions seems a possibility. It's a small world after all!" [27: Excerpt | Full document]
The ChemRisk Documents
The truth was more complicated than that, but Beaumont had uncovered the basic outline of the fraud. The details of ChemRisk's deception emerged from documents filed in the Kettleman City lawsuit against PG&E.
In 1995, PG&E's lawyers had suffered a major setback in the Hinkley lawsuit: The judge had admitted the 1987 study was an important piece of evidence that chromium-6 was harmful to human health. [31,32] Under contract to PG&E, McLaren/Hart-ChemRisk set out to get additional information that might cast doubt on the study. McLaren/Hart had offices in China, and employees there managed to track down the elderly Dr. Zhang, who was retired from the JinZhou health station, spoke little English and had no computer. [33,34,35,36]
In April 1995, Zhang signed a consultant's contract with McLaren/Hart. According to the documents, he was initially paid $250 a month to provide "document review and consultation regarding epidemiology, groundwater contamination and health effects of chromium."  All told, he was paid less than $2,000; ChemRisk's fees from PG&E's lawyers were between $20,000 and $30,000. [38,39,40,41]
It's unclear if, or at what point, Zhang knew he was really working for PG&E. In a 1997 deposition, a ChemRisk scientist named Brent Kerger, who oversaw the firm's work on the fraudulent study, testified that he didn't think this information "would be of particular interest" to Zhang, but that he later told Zhang when asked about it.  But PG&E's attorneys knew McLaren/Hart had retained Zhang, and why. Asked in the deposition, "Did ChemRisk inform PG&E's counsel that ChemRisk was involved in getting the Zhang '97 article published?," Kerger replied: "Yes, they knew." 
Although Zhang worked on the project, ChemRisk was clearly responsible for most of the work and content of the 1997 paper. An August 1995 memo from Bill Butler describes Zhang's role merely as "research assistance." [44: Excerpt | Full document] In the memo, Butler complains that: "It is at times difficult to convince Dr. Zhang of the importance to us of the specific details of his studies so that we can execute our own analyses." [Emphasis added.] [44: Excerpt | Full document] Kerger later testified that "all of the numerical analyses that were done with respect to the ... cancer death rates ... was [sic] the responsibility of Bill Butler." 
"I Guess It Wasn't Standard Practice"
Other testimony revealed that all of the drafts of the article were typed by Tony Ye — who was just out of college and seems to have been assigned to the project because he spoke Chinese — in English on ChemRisk computers and changes were made by a ChemRisk word processing program. [46,47] More than ten early drafts of the paper show handwritten changes made by ChemRisk employees and the cover pages of two early drafts of the article actually state that it was "by ChemRisk," apparently before Ye realized the firm's role should be covered up. [48,49,50,51,52,53,54,55,56,57,58]
No attempts were made to get the study published in a Chinese-language journal; it is unclear as to whether a Chinese version of the final article ever existed or if the final JOEM article was ever sent to Zhang. [59,60] In a 1996 memo to PG&E's lawyers, ChemRisk's Brent Kerger lists the JOEM article as one of eight "ChemRisk Chromium Manuscripts in Peer-Reviewed Scientific Journals." (Notably, it was the only one that did not list at least one ChemRisk employee as an author.)  ChemRisk actually misspelled Zhang's name on all of its drafts of the manuscript, on the cover letters sent to journals, and in the final published article itself. [2,48,49,50,51,52,53,54,55,56,62]
In December of 1995, ChemRisk finished the final draft of the paper. Although very early drafts of the paper mentioned ChemRisk's involvement and a draft cover letter to another journal directed correspondence to Zhang care of ChemRisk, neither the final manuscript article nor the final cover letter included any mention of ChemRisk. [48,49,50,51,52,53,54,55,56,57,58] Rather, the cover letter was typed on ChemRisk computers but printed on plain white paper, and directed correspondence to be sent to Tony Ye's home address. [48: Excerpt | Full document, 49: Excerpt | Full document, 63,64] When asked under oath whether this was unusual procedure, Kerger responded: "I guess it wasn't standard practice." 
ChemRisk wanted to get the paper published quickly because PG&E's negotiations over the Hinkley settlement were coming to a close. The firm submitted the article to two journals at the same time — JOEM and the Archives of Environmental Health — even though this violated both journals' policies against simultaneous submissions. [66,67] In depositions, ChemRisk employees claimed not to know of the journals' policies, but not only are such policies standard in the academic world, ChemRisk signed forms promising that the study was not being considered anywhere else. Compared to ChemRisk's other deceptions, the simultaneous submission is a minor sin, but evidence of the firm's willingness to disregard ethics to its clients' advantage.
In May 1996, Tony Ye found that the paper had been accepted by both journals.  ChemRisk withdrew the paper from the Archives of Environmental Health and pursued publication with JOEM. A couple of weeks later ChemRisk sent the following memo to PG&E's attorneys:
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 Occupational and Environmental Medicine. Dr. Zhang's previous paper (which is cited by ATSDR) stated 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." 
The memo's reference to ATSDR signifies PG&E's concern about the fact that the Agency for Toxic Substances and Disease Registry had cited the 1987 Zhang study in support of a connection between chromium-6 exposure in drinking water and cancer. To ChemRisk, this was the strongest indicator of their success in getting the findings of Zhang's study reversed.
Zhang died sometime before 2001 so it is impossible to know what he thought of the final article that bears his name. Much of the language tempering the study's conclusions in early drafts is absent in the final article. An earlier draft said: "These results suggest that the high cancer death rates in this area may be partially attributed to lifestyle or environmental factors not related to the chromium (VI) contamination," while the final paper made a much stronger assertion: "Nonetheless, these results suggest that lifestyle or environmental factors not related to the chromium (VI) contamination are the likely source of the variation in these cancer rates." [56: Excerpt | Full document, 2]
Thirteen Ethical and Scientific Flaws
There is evidence Zhang wasn't happy with ChemRisk's analysis. In a September 6, 1995 memo to Butler, Ye wrote: "Dr. Zhang did not totally agree with us with the conclusion section" and that he had "to make a little compromise." [70: Excerpt | Full document] But ChemRisk certainly didn't display any qualms about compromising the standards of sound science. After reviewing the JOEM paper, the original 1987 Zhang and Li study, translations of Zhang's earlier work published in China, as well as earlier drafts of the 1997 manuscript, court depositions, and internal documents obtained through independent litigation, OEHHA drew up a list of thirteen ways in which ChemRisk committed ethical or scientific breaches, including:
- Failure to disclose who wrote the manuscript.
- Failure to disclose that the study was funded by PG&E.
- Falsely stating in the published paper that stomach cancer rates weren't available for the province.
- Basing analysis on the level of contamination detected in the wells in 1965, knowing that by the end of that year the picture of contamination in the wells had dramatically changed.
- Ignoring useful data that were readily available.
- Misrepresenting the study design in several ways to make it seem stronger.
- Failing to disclose key facts about the data presented.
- Simultaneous submission to two journals. 
The lies, errors, and misrepresentations in the 1997 JOEM article don't stop even there. EWG's review of court documents and depositions show that several of the high chromium-6 concentrations reported in Zhang's original 1987 study were left out of the 1997 paper.  Worse, a graphic reporting chromium-6 concentrations in the wells of the Chinese village most affected by chromium contamination also erroneously shows the chromium-6 levels of the wells in a different, less contaminated village. 
In addition, OEHHA pointed out that the "13-year observation period after the first exposure was relatively short for a study of human cancer, because many cancers could occur after the end of the observation period." [71: Excerpt | Full document] In other words, even if all of the analysis had been conducted correctly, a negative finding between chromium-6 exposure and cancer would still be considered suspect simply because it often takes longer than 13 years for cancer to develop after the first exposure to a carcinogen.
1965 — 1974: Water sampling and health surveys near a chromium processing facility in China's Liao Ning province find massive contamination of groundwater and many residents suffering symptoms of chromium poisoning.
1987: JianDong Zhang and XiLin Li publish a study in the Journal of Chinese Preventive Medicine showing an association with chromium-6 exposure to high rates of cancer in the contaminated area.
December 1987: Pacific Gas & Electric Co. advises California regulators they have detected chromium-6 in a Hinkley monitoring well at more than 10 times the state's standard for total chromium.
May 1993: Residents of Hinkley sue PG&E for releasing wastewater contaminated with chromium-6 into the town's groundwater. The 1987 Zhang study is later admitted as evidence, setting off an effort by PG&E consultants McLaren/Hart-ChemRisk to find the study's author.
April 1995: Zhang signs a contract with McLaren/Hart. He is paid $250 a month to provide "document review and consultation regarding epidemiology, groundwater contamination and health effects of chromium."
December 1995: ChemRisk completes its "clarification" of Zhang's 1987 study, omitting data showing higher levels of cancer in the contaminated villages than in the surrounding province. ChemRisk's paper is submitted under Zhang's name to two peer-reviewed journals.
May 1996: ChemRisk's paper is accepted by the Journal of Occupational and Environmental Medicine (JOEM) and the Archives of Environmental Health.
July 1996: PG&E settles the Hinkley lawsuit by paying 650 residents damages of $333 million.
April 1997: The article is published under Zhang's byline in JOEM. It is subsequently cited by the EPA and Agency for Toxic Substances and Disease Registry as evidence that chromium-6 in drinking water does not cause cancer.
March 2000: The film Erin Brockovich, based on the Hinkley case, is released.
September 2000: A new state law requires testing for chromium-6 in Southern California water supplies and an assessment of its health risks.
October 2000: A lawsuit alleging chromium-6 contamination is filed against PG&E by residents of Kettleman City, Calif., eventually including 1,250 claims.
March 2001: The state asks the University of California to convene an expert panel to address whether chromium-6 in water causes cancer. Panel includes former McLaren/Hart and ChemRisk executive Dennis Paustenbach. When the panel's report is released, it concludes that a chromium-6 drinking water standard is not needed, pointing to the 1987 Zhang study as evidence.
August 2001: OEHHA scientist Jay Beaumont takes another look at the 1997 JOEM article and finds "several notable limitations and oddities." He finds that stomach cancer rates in the contaminated villages were much higher than in the surrounding province. He learns that Zhang is dead, but had been a McLaren/Hart consultant.
October 2001: New state law requires adoption of a chromium-6 drinking water standard by January 1, 2004.
December 2002: Depositions and documents filed in the Kettleman City case against PG&E detail efforts by McLaren/Hart-ChemRisk to reverse findings of Zhang's study.
April 2003: At a special legislative hearing, evidence is presented of conflicts of interest among members of the UC panel, including Paustenbach. OEHHA says it will not use the panel's report in setting its public health goal for chromium-6.
Fall 2005: A new draft PHG for chromium-6 is expected from OEHHA.
January 2006: Case brought by Kettleman City, Calif., residents against PG&E over hexavalent chromium contamination of air and drinking water is scheduled to go to trial.
McLaren/Hart Environmental Engineering Corporation. 1995. Authorization letter/Task Order. September 11, 1995. Contract between PG&E and Jian Dong Zhang. Faxed to Tony Ye at ChemRisk. Bates stamps: TY-0459 and TY-0460.
Drafts of Zhang Paper
 Zhang, JianDong and XiLin Li. 1987. [Chromium pollution of soil and water in Jinzhou]. Zhonghua Yu Fang Yi Xue Za Zhi [J. Chinese Prevent. Med.] 21(5):262-4.
 Zhang, JinDong and ShuKun Li. 1997. Cancer mortality in a Chinese population exposed to hexavalent chromium in water. JOEM 39(4):315-319.
 ChemRisk's website: http://www.chemrisk.com/ Accessed on September 30, 2005.
 US Department of Energy and U.S. Department of Health and Human Services. 2005. Agenda for HHS Public Health Activities (For Fiscal Years 2005—2010) at U.S. Department of Energy Sites. January, 2005. Available at: http://www.cdc.gov/niosh/pdfs/hhsdoe_2005-2010.pdf
 ChemRisk's website: http://www.chemrisk.com/team/paustenbach.htm Accessed on September 30, 2005.
 Center for Science in the Public Interest. 2005. Integrity in Science Database. Available at: http://www.cspinet.org/integrity/index.html Accessed on September 30, 2005.
 Lane, A. 2004. When corporations need an expert, he gladly answers the call. Newark Star-Ledger. March 7, 2004.
 Weiss, R. 2002. Paustenbach CDC appointment: HHS Seeks Science Advice to Match Bush Views. Washington Post. Tuesday, September 17, 2002. Page A01.
 Deposition of Brent Kerger. Wednesday, December 4, 2002. Volume 1, page 165, line 3.
 US Environmental Protection Agency. 2001. Inorganic Chromium - Report of the Hazard Identification Assessment Review Committee. Available at: http://www.epa.gov/oscpmont/sap/2001/october/arsenicgraphdata.pdf
 Agency for Toxic Substances and Disease Registry. 2000. Toxicological Profile for Chromium. US Department of Health and Human Services. Available at: http://www.atsdr.cdc.gov/toxprofiles/tp7.html
 Chromate Toxicity Review Committee. 2001. Scientific review of toxicological and human health issues related to the development of a Public Health Goal for chromium (VI). August 31, 2001. Available at:
 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: http://www.sen.ca.gov/health/CHROMIUM_VI_TRANSCRIPT_28FEB03.DOC
 California Department of Health Services. 2005. Chromium-6 in Drinking Water: Timeline. Available at: http://www.dhs.ca.gov/ps/ddwem/chemicals/chromium6/Cr+6timeline.htm Accessed on September 30, 2005.
 US Environmental Protection Agency. 2000. Hazard summary for chromium compounds. Available at: http://www.epa.gov/ttn/atw/hlthef/chromium.html
 US Environmental Protection Agency, Toxicological Review of Hexavalent Chromium (CAS No. 18540-29-9), August 1998. Available at: http://www.epa.gov/iris/toxreviews/0144-tr.pdf
 International Agency for Research on Cancer (IARC). 1990. Monographs on the Evaluation of Carcinogenic Risks to Humans. Chromium and Chromium Compounds. Volume 49, 1990. Available at: http://www-cie.iarc.fr/htdocs/monographs/vol49/chromium.html
 National Toxicology Program. 2005. 11th Report on Carcinogens. Chromium Hexavalent Compounds. Available at: http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s045chro.pdf
 US Department of Labor, Occupational Safety & Health Administration. 2004. Occupational Exposure to Hexavalent Chromium; Proposed Rule. Federal Register: October 4, 2004 (Volume 69, Number 191). Available at: http://www.osha.gov/FedReg_osha_pdf/FED20041004-PRE.html
 Costa, M. 1997. Toxicity and carcinogenicity of Cr(VI) in animal models and humans. Crit Rev Toxicol 27(5):431-42.
 California Department of Health Services. 2004. Chromium-6 in Drinking Water: Background Information. Available at: http://www.dhs.ca.gov/ps/ddwem/chemicals/chromium6/Cr+6backgroundinfo.htm
 World Health Organization. 1996. Guidelines for Drinking-Water Quality, 2nd Ed., Vol. 2. Health Criteria and Other Supporting Information, Inorganic Constituents and physical parameters, World Health Organization, Geneva. Available at: http://www.who.int/water_sanitation_health/dwq/gdwq2v1/en/index1.html
 Office of Environmental Health Hazard Assessment. 2003. Draft Public Health Goal for Hexavalent Chromium in Drinking Water. December, 2003. Obtained by EWG through public records request.
 Email from Jay Beaumont to George Alexeeff. August 7, 2001.
 Email from Jay Beaumont to Joan Denton. October 5, 2001.
 Email from Jay Beaumont to Richard Sedman. September 10, 2001.
 Email from Jay Beaumont to George Alexeeff, Bob Howd, Ling-Hong Li, Tom McDonald, Martha Sandy, Richard Sedman and Lauren Zeise. September 14, 2001.
 Bustillo, M. 2003. PG&E Assailed in Hearing Over Chromium 6; The utility boycotts session in which Erin Brockovich says firm had role in downplaying health risks of pollutant. Los Angeles Times. March 1, 2003.
 Polley, MB. 2002. Journal accused of letting industry ties cause bias. Pesticide & Toxic Chemical News. December 16, 2002.
 Lane, Alexander. 2004. Polluters gain as Jersey lifts limit for toxin. March 7, 2004. Newark Star-Ledger.
 Kerger Deposition. Volume 1, page 165, line 7.
 Deposition of Brent Kerger. Tuesday, February 18, 2003. Volume 2, page 327, line 12.
 Deposition of Tony Ye. Thursday, December 12, 2002. Volume 1, page 44, line 21; page 243, line 10.
 Kerger Deposition. Volume 2, page 514, line 8.
 Deposition of Tony Ye. Friday, December 13, 2002. Volume 2, page 516, line 21.
 Kerger Deposition. Volume 1, page 287, line 14.
 McLaren/Hart Environmental Engineering Corporation. 1995. Authorization letter/Task Order. September 11, 1995. Contract between PG&E and Jian Dong Zhang. Faxed to Tony Ye at ChemRisk. Bates stamps: TY-0459 and TY-0460.
 Letter from to Guang Zhu to Chris Daniels, McLaren Hart International. November 21, 1995. Bates stamp TY-100.
 Kerger Deposition. Volume 1, page 42, line 23.
 Kerger Deposition. Volume 1, page 47, line 6.
 Ye Deposition. Volume 2, page 369, line 4.
 Kerger Deposition. Volume 1, page 216, line 18.
 Kerger Deposition. Volume 1, page 43, line 19.
 Memo from Bill Butler to Brent Kerger. August 7, 1995. Bates stamps: WB-0117 to WB-0122. See page 2 of memo.
 Kerger Deposition. Volume 1, page 160, line 3.
 Ye Deposition. Volume 2, page 516, line 21.
 Kerger Deposition. Volume 2, page 514, line 8.
 Draft paper with Bates stamps: TY-0102 to TY-0112.
 Draft paper with Bates stamps: TY-0089 to TY-0097.
 Draft paper with Bates stamps: TY-0469 to TY-0476.
 Draft paper with Bates stamps: WB-0215 to WB-0220 and WB-0204 to WB206.
 Draft paper with Bates stamps: WB-0207 to WB-0209.
 Draft paper with Bates stamps: WB-0200 to WB-0203.
 Draft paper with Bates stamps: WB-0181 to WB-0184.
 Draft paper with Bates stamps: WB-0175 to WB-0179.
 Draft paper with Bates stamps: WB-0164 to WB-0167.
 Draft paper with Bates stamps: WB-0062 to WB-0070.
 Draft paper with Bates stamps: TY-0113 to TY-0119.
 Ye Deposition. Volume 2, page 330, line 23; page 361, line 2.
 Ye Deposition. Volume 1, page 157, line 20.
 Letter from Brent Kerger to Steven Hoch, Esq. May 20, 1996. Also faxed to Mike Whelan, PG&E May 20, 1996. Bates stamps: BRP 0331 to BRP 0335.
 Ye Deposition. Volume 2, page 332, line 22.
 Ye Deposition. Volume 1, page 64, line 24; page 66, line 16; page 68, line 24.
 Kerger Deposition. Volume 2, page 402, line 13.
 Kerger Deposition. Volume 1, page 264, line 4.
 Fax from Tony Ye to Gwen Corbett. January 24, 1996. Bates stamps TY-0529 to TY-0530.
 Ye Deposition. Volume 1, page 67, line 17.
 Memos from Tony Ye to Brent Kerger and Bill Butler. April 19 and May 20, 1996. Bates stamps TY-0540 and TY-0541.
 Memo from Gwen Corbett to Greg Read et al. June 5, 1996. Re: Acceptance of China Paper. Copied to Brent Kerger. Bates stamp: BRP 0329.
 Memo from Tony Ye to Brent Kerger. September 6, 1995. Bates stamps: WB-0173 to WB-0179. See page 1 of memo.
 Internal OEHHA memo dated March 28, 2003. Scientific issues regarding Zhang and Li, 1997. Obtained through public records request.
 Kerger Deposition. Volume 2, page 379, line 24.
 Kerger Deposition. Volume 2, page 394, line 8.
 Letter from Dennis Paustenbach to George Alexeeff. July 17, 2000.