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Cancer death rate normal among ex-Ciba workers, study finds
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Published in the Asbury Park Press
By JEAN MIKLE
TOMS RIVER BUREAU
DOVER TOWNSHIP -- Cancer death rates among former employees of the Ciba-Geigy Corp. are no higher than rates for the general population of New Jersey and the nation, according to an epidemiological study of more than 3,000 former workers at the chemical plant.
"It encompasses 44 years and almost 3,300 people and the bottom line is, we're very pleased with the results," said Eugene W. Gessler, Toms River site manager for the company, now known as Ciba Specialty Chemicals Corp. He said that more than 2,500 former Ciba employees were mailed a copy of the study results yesterday.
The study, which cost about $320,000, is a follow-up to three previous studies of the health of former Ciba workers, and confirms prior findings that the overall health of the workers is actually better than that of the general population of New Jersey and the nation, according to Dr. Elizabeth Delzell, one of two University of Alabama, Birmingham, researchers who conducted the study.
The plant, which manufactured dyes, additives and plastics, was one of Ocean County's largest employers from the time it opened in 1952 until it ceased all manufacturing operations in December 1996.
Results of the study were also shared with approximately 40 workers who remain at the plant to complete clean-up of the site. Ciba's dye plant was placed on the federal Superfund list in 1982 after carcinogenic chemicals were found to have been dumped in the soil.
The 18-month-long epidemiological study reviewed mortality rates among 3,266 former Ciba employees who worked at the plant for at least six months during the period from 1952 until 1995. Of that number, 728 have died, Delzell said.
There were 225 deaths from all types of cancers, slightly lower than the 232 cancer deaths that would be expected when comparing the former workers with the population as a whole.
The researchers did find an increase in cancer fatalities among 89 Ciba workers who were previously employed at the Cincinnati Chemical Works and came to Toms River after the Cincinnati plant shut down in 1959.
Delzell said the former Cincinnati employees had higher than expected rates of bladder cancer, which has been linked to exposure to benzidine and beta-napthylamine, two chemicals used in the manufacture of dyes, tires and rubber.
Gessler said that while benzidine was used at the Toms River site, it was never manufactured there. It was manufactured at the Cincinnati plant.
Among Ciba employees who never worked at the Cincinnati plant, the cancer mortality rate was about 5 percent lower than expected, Delzell said.
Higher than expected rates of lung, central nervous system and stomach cancer were found among employees in certain areas of the plant, Delzell said. But she said there was no scientific evidence that those increases were related to employment at Ciba. She said researchers found inconsistent patterns in the number of years workers were employed and the likelihood that they would develop cancer.
For example, in some cases workers who were employed at Ciba for a shorter period developed cancer, while workers with longer stays at the plant did not.
Researchers were also hampered because in most cases, they did not have information about employees' lifestyles or previous employment histories that could be risk factors for contracting cancer, Delzell said. They did not know if employees smoked, or had family histories of cancer, she noted.
The overall mortality rate of Ciba employees was about 10 percent less than what would be expected based upon the state's mortality rates, Delzell said.
To conduct the latest study, researchers relied on employment records to find out when and where people worked, and then looked at death certificates to determine the causes of death for former employees, Delzell said.
She said researchers did not attempt to interview the former employees and did not conduct an incident study, which would look at the number of incidents of cancer and other diseases that did not result in death, as well as the deaths caused by the diseases.
Gessler said the company has no plan to conduct a more in-depth study, but has not entirely ruled it out.
"We are leaving the door open," he said.
Published: July 2, 1998
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