COPPERHILL, Tenn. — A scientist who worked on a study of Copperhill acid plant workers last week rebutted a claim that the study relied on incorrect information.
Dr. Gary Marsh, a University of Pittsburgh professor, said the study was an expansion of one begun in 1980 to see if there was a link between exposure to acid byproducts and cancer deaths. The study found no such link among workers at the former Tennessee Chemical Co.
“Neither we nor anyone else had any way of predicting the outcome of the updated study,” Dr. Marsh said. “Although the updated study was driven by community rather than worker concerns about elevated health risks, our overall conclusions were similar.”
When the results were made public March 2, former plant worker Nick Wimberly said he believed researchers relied on autopsy reports that failed to include cancer diagnoses.
Mr. Wimberly said most deaths were blamed on heart disease and other causes, even though many workers knew they had cancer.
“We just couldn’t get folks to look at that,” he said.
The study by Dr. Marsh and Dr. Nurtin Esmen examined health records of 2,422 men who worked in the smelter, mill or sulfur plant at Copperhill for three or more years between January 1946 and April 1996.
The results showed cancer death rates for acid plant workers were no higher, and in some cases lower, than those of the general population. The study did not find statistically significant evidence of higher mortality rates from any disease or condition studied.
Allison Tepper, spokeswoman for the U.S. Centers for Disease Control and Prevention, said the study was performed for the National Institute of Occupational Safety and Health.
She said researchers used well-established methods and that it was unlikely that deaths were incorrectly attributed.
“The statistical analysis is based on the underlying cause of death,” Ms. Tepper said. “This means that if a person had a heart attack but also had lung cancer, the lung cancer information was included in the analysis.”
She said residents raised the death-certificate question early in the study and the researchers addressed it when they reviewed the documents.
Some residents and former workers have believed for years that living and working near the plant contributed to higher rates of cancer.
They described the dense, paint-dissolving fogs, orange smoke and effluents emitted from the plant and said they couldn’t believe there was no impact on health.
The study took nearly four years and was documented in a 50-page report.
The reviewers made several suggestions for further analysis and discussion, Ms. Tepper said, but the findings don’t provide any evidence indicating that further study is needed.
