A former Dow Chemical researcher has reported significant levels of chromosome damage among Dow workers exposed to less benzene than the current federal standard allows.

Abnormalities of chromosomes - the carriers of heredity in every body cell - have been associated with increased risk of cancer and birth defects.

Yet Dow, one of the nation's largest users of benzene, withheld the potentially controversial findings last summer during a series of federal hearings to set a new standard for workers exposed to benzene.

The new standard would apply to an estimated 600,000 industrial workers throughout the country who are exposed to benzene daily.

The new findings of genetic damage from low-level benzene exposure in a study of 52 workers were reported to Dow medical officials in June 1977 by a Dow geneticist, Dr. Dante Picciano, who resigned last March in protest against the corporation's refusal to disclose the information.

The chemical industry has long contended to federal regulatory agencies that benzene has not been shown to be dangerous at any but high levels - above 100 parts per million (ppm).

Picciano is the first scientist to report chromosome damage at levels below the current 10 ppm federal standard. His methodology has been favorably reviewed by three scientists who consulted for Dow on the study. Picciano has released copies of their opinions, which initially were communicated to the company privately last summer.

Benzene, a clear liquid, is one of the most common industrial chemicals. It is a basic ingredient in the production of plastics, synthetic rubbers and fibers, pesticides and pharmaceuticals. It is also used as a solvent and as a widely used additive - averaging 2 percent - in gasoline.

Benzene is known to cause leukemia and other human blood disorders. But there is wide disagreement on how much exposure it takes to produce cancer.

The petrochemical industry, in hearings, petitions and litigation, has persistently fought attempts by the federal Occupational Safety and Health Administration (OSHA) to lower benzene exposure levels from 10 to 1 ppm averaged over an eight-hour workday, contending there is no evidence to support such a standard.

"I had to quit to get this out," said Picciano, who is now working for OSHA's office of carcinogen identification and classification. He said he considers Dow's actions in response to his study "unethical" and "immoral."

In response, Dow officials said in interviews at the Dow research laboratory here that they disagree with Picciano's findings and his charges.

Dow considers the current 10 ppm federal benzene standard safe. Corporate officials said the workers Picciano surveyed were exposed to higher levels - at times exceeding by tenfold the 10 ppm level he reported.

Dow's data, however, does not support this claim, according to Picciano and an informed source who asked not to be named, as well as data Picciano produced. This data, they say, indicates that benzene exposures to the Dow workers studied were consistently below 10 ppm.

Picciano studied 52 workers from two plants at the 3,000-acre Freeport complex, one of the work's largest chemical plants.

Here at Dow's research laboratory, Picciano studied white blood cells from the workers for several types of chromosomal aberrations.

He found a twofold increase in one category of abnormality (broken chromosomes) and a tenfold increase in another category (broken chromosomes and chromosome rearrangements) as compared to a control group of 44 persons applying for jobs at Dow.

He also found a correlation between the degree of benzene exposure and chromosome damage.

"It's really important study," said Dr. Marvin Legator, a Dow consultant and geneticist and director of environmental toxicology and epidemiology at the University of Texas Medical School in Galveston.

Picciano is "a first rate investigator," Legator added. "I don't know of anybody who's seen the data who would say anything negative about it."

The study is significant, he said, because "there is no question but what chromosome abnormalities are associated clinically with cancer. The association there is almost absolute."

Legator also said that genetic tests should be widely used in industry for early detection of adverse health effects.

"With few exceptions," he said, "most of the industrial chemicals that have been identified as carcinogens or mutagens could have been detected earlier in screening workers for cytogenetic effects (cellular damage) and other abnormalities."

Two other consultants to Dow, Dr. Elbert B. Whorton Jr., associate dean and director of biometry at the University of Texas, and Dr. Cecil Jacobson, associate clinical professor of obstetrics and gynecology and adjunct professor of genetics at George Washington University, also reviewed the study and agreed with the thrust of Picciano's conclusions.

Another researcher, Dr. Jeanne Manson, a toxicologist and assistant professor of environmental health at the University of Cincinnati said, "I think it is a very good study as far as cytogenetic studies go."

"There's no doubt that when you have an exposed population with a high incidence of genetic damage, then something is goind on. These workers are definitely at risk. They should not have high levels of chromosome breakage."

Dow officials said they have not informed workers of Picciano's report. They have had trouble interpreting the data, they explained.

"This is an area where the art and the science is developing and there is a lot of difference of opinion on how the data should be analyzed," said Dr. John Venable, director of industrial medicine for Dow's Texas Division.

Venable said Dow did not inform workers of Picciano's findings because the company did not want to "err by finding a false positive - placing an undefined albatross on the back of the worker. This is very unfair to the employe."

Venable pointed out that a Dow consultant had reviewed the same data Picciano used and found 50 of the 52 workers to be "normal." The two that were abnormal, he maintained, "had nothing to do with benzene."

That consultant, jacobson, Picciano's former teacher, said his evaluation is not in conflict with Picciano's.

Jacobson explained that individual medical evaluations showed that 50 of the 52 workers fell within a normal range clinically - since everyone has a small background level of chromosome damage - but studied statistically, compared to controls, significant differences between the two groups could be detected.

In reviewing Picciano's paper last July, Jacobson called it "an excellent paper which is the culmination of years of technical developments within Dow . . ."

Jacobson said that ". . . due to the persistence of structural defects seen in this study as well as in previous samples on these same men, chronic low-dose exposure [to benzene] may explain their structural anomalies"

In July, shortly after Picciano first presented his findings to corporate research officials, his supervisor, Dr. D. J. Kilian, wrote to another Dow official, Dr. Benjamin Holder, director of medical services for Dow U.S.A.

"The results are not what we expected," Kilian wrote, but it identifies an unsuspected occupational health hazard and, therefore, appropriate steps must be taken to disseminating the information through EPA [Environmental Protection Agency], NIOSH [National Institute for Occupational Safety and Health], or the medical literature."

Yet later that month, at OSHA hearings on a new benzene standard, Dow officials did not mention Picciano's findings.

Instead Dow submitted three other corporate studies that one company official characterized as showing "no significant abnormalities . . . that would relate to benzene exposure."

Dow finally released a version of the Picciano study last March 1 after repeated requests starting in October 1977 from Dr. Peter Infante, then a NIOSH epidemiologist.

Infante asked Dow for either the completed study or raw data at the earliest possible date, noting in one letter that "this data may be pertinent to several regulator decisions affecting the worker and the population at large."

The results Dow sent to NIOSH and EPA in March, shortly after OSHA published a new benzene standard, acknowledged significant chromosomal damage. But Dow's acknowledgement was based on exposures to benzene which the company said were at times much higher than at the levels Picciano reported.

Picciano said that after he first presented his results to corporate health researchers in June 1977, corporate interest in continued worker studies began dropping off and he eventually found his access to employe exposure data restricted.

Picciano left Dow in March.

Dow officials said they have not repeated studies on the exposed benzene workers, but plan to do so.

Corporate research spokesmen said Dow is dedicated to protecting its employes and spends $1 million a year in medical research.

Furthermore, Holder said, "We've been very proud that we have been pioneers" in genetic research.