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23 janvier, 2008 16:52

U.S. health officials had criticized two Rohm & Haas studies.

By Tom Avril

Inquirer Staff Writer

Federal health officials last month issued a harsh critique of a Rohm & Haas investigation into a series of brain cancers at its main research center, and the company said yesterday that it would hire an external academic team to take over the investigation.

The change in approach comes three weeks after the Philadelphia chemical-maker told employees there was no statistically significant increase in brain cancers at the research center in Spring House, Montgomery County.

The federal review, conducted at the company's invitation by the National Institute for Occupational Safety and Health (NIOSH), found no specific evidence to counter that statement. But in the critique - dated Dec. 18, two weeks before the good-news message was sent out to employees – agency epidemiologist Mary Schubauer-Berigan detailed numerous flaws in Rohm & Haas' two brain-cancer studies.

Company researchers counted employee deaths using "a scattershot approach," and they estimated employees' exposure to chemicals in a way that was "highly unusual" and "very difficult to follow," Schubauer-Berigan wrote. She also faulted the analysis of brain-cancer rates because it did not treat lab employees and office staff separately, and suggested that that approach might dilute any potential findings of statistical significance.

"Including people who are really not exposed with those who are," she said in a telephone interview yesterday, "can be a problem." The critique of the research was not meant to imply that any flaws were intentional, she added.

The latest twist comes six years after the company first decided to undertake an investigation. One study was completed in January 2004, the second earlier this month, although neither has been published and no smoking gun has been found to suggest why more than 12 people are dead.

Meanwhile, the doctor who conducted the two internal studies, Rohm & Haas epidemiologist Arvind Carpenter, retired Dec. 31, company officials said yesterday. The departure was by his choice and had nothing to do with the company's opinion of his work, said vice president Phil Lewis.

To the contrary, Carpenter wanted to retire sooner but was asked to stay until drafts of the two studies were completed, Lewis said. The switch to an external investigation was made merely to be as "transparent" as possible, he said.

"I have full confidence in the work that Arvind Carpenter has done," said Lewis, who is also a physician and serves as corporate director of environmental, health, safety and sustainable development. "He is a great scientist."

Carpenter, 60, said in a phone interview that he retired because of personal issues. He said some of the NIOSH criticisms might have arisen because the reviewers did not have all the information. They were supplied with drafts of the two studies, which have yet to be published.

"I believe we did very good scientific work," Carpenter said. "Some of their comments are really good; some of them are really superficial. Some of them are coming up because they probably don't understand all the work we did. You cannot write everything in the manuscript."

Asked why the NIOSH criticisms were not mentioned when employees were told in a letter dated Jan. 2, two weeks later, that there was no excess in brain cancers, Lewis said he had not seen the agency's review at that point. He characterized the review as "straightforward" and not unusually critical.

Aaron Freiwald, a lawyer representing the survivors of several brain-cancer victims who worked at Spring House, said otherwise.

"NIOSH has essentially told Rohm & Haas, 'Everything you've done is scientifically flawed, and you have to start over,' " Freiwald said.

Besides her numerous criticisms of the studies' methodology, the NIOSH epidemiologist said written descriptions of the research were incomplete.

"The Discussion is extremely poor," wrote Schubauer-Berigan. "The many limitations of the study," she wrote in the last of 17 comments on the later of the two studies, "are not even broached. The conclusion that no brain cancer elevation was observed is presented as definitive, despite the near-doubling that was observed and the extremely low power of the study to detect statistical significance for this level of excess."

In a cover letter addressed to Lewis, the chiefs of two branches within NIOSH recommended that outside scientists be brought into the investigation.

Yesterday, Lewis and Spring House site manager David Greenley wrote in another letter to current and former Spring House employees that, from now on, the investigation will be handled by a NIOSH-funded university research center. There are more than a dozen such centers; Lewis said he is in talks with several.

"Although considerable effort has gone into our epidemiologic investigation to date, we believe this decision best serves our investigation aims and objectives in keeping with sound science, transparency, and independence," Lewis and Greenley wrote.

The company first talked about launching an investigation in the fall of 2001, and formally notified employees and retirees in 2002 that one was under way. Officials said then that they knew of 10 brain-cancer victims, and that a preliminary estimate suggested that number was twice what would be expected. Earlier, Carpenter had estimated that the brain-cancer rate among workers might be as much as five times the average in the general population.

When the first study was completed in January 2004, company officials said they knew of 12 brain-cancer cases and three additional benign brain tumors but that there was no apparent association with exposure to any chemicals in the workplace.

Two more cases have come to light since then. Freiwald, the attorney, has argued that at least two more on top of those should be included in the tally; those employees were not permanently assigned to Spring House but worked there frequently.