Contamination in Wells G and H

In the spring of 1979 it was discovered that someone had left 184 barrels of industrial waste on a plot of land in northeast Woburn just a half mile from Wells G and H. The barrels were removed before they leaked, but given the proximity to the wells, a state inspector tested water samples from Wells G and H. On May 22 the results showed that both wells were heavily contaminated with trichloroethylene (TCE), an industrial solvent used to dissolve grease and oil. The concentration of TCE in Well G was 267 parts per billion (ppb), and the levels in Well H were 183 bpp. The wells also contained tetrachloroethylene, also known as "perc," another industrial solvent. The concentrations of both contaminants were above the maximum allowable limits, and the wells were shut down.

Other contaminants had recently been discovered in north Woburn at the site of the old Merrimac Chemical Company. A partially filled lagoon was found to contain arsenic, lead, and chromium. The construction crew that had found the lagoon also found several buried pits containing the rotting remains of animal hides and slaughterhouse waste. .

In the audio file below Woburn Times reporter Charlie Ryan discusses the discovery and extent of the contamination found in the area of Wells G and H.


The Leukemia Cluster

There was widespread concern In the wake of the disclosures about the contaminants found at the old Merrimac Chemical Company and the contamination of Wells G and H with TCE and perc. Reverend Bruce Young, the minister at Trinity Episcopal Church in Woburn, had had many conversations with Anne Anderson about her belief that something in the environment was responsible for the leukemia cases in Woburn; by this time Anne knew of eight cases. When Reverend Young read the newspaper reports, Anne's beliefs suddenly seemed credible. It seemed to Young that the next logical step was to determine how many cases of leukemia there were in Woburn, but at the time neither the state nor the city had a surveillance system that kept track of incident cancer cases.

When confronted with an unusual case of disease or an unusual cluster, one of the key things that should be done is to actively look for more cases. If one can develop a case series, it makes it easier to figure out how the occurrence of disease relates to personal characteristics, place (where the cases lived or worked), and time (when the disease cluster began and how the frequency of disease changed over time).

For a more detailed discussion, see the online learning module of Descriptive Epidemiology.

Reverend Young decided to "...write a letter to be published in the Woburn Daily Times asking parents who had a child diagnosed with leukemia in the last fifteen years to come to a meeting at Trinity Episcopal." [Source]

More than thirty people attended the meeting on October 4, 1979, including parents of children with leukemia and concerned citizens. reverend Bruce distributed a survey, and when they were returned, they had identified 12 leukemia cases over a 15-year period. Eight of the cases occurred in east Woburn, and six of those were in the Pine Street neighborhood.just south of the "Fifteen Acres" plot of land and Wells G and H.

Was this really a cluster? Some epidemiologists attributed apparent clusters to the "Texas Sharpshooter Effect." Was the apparent cluster in the Pine Street area of Woburn real?


The key question, of course, was whether twelve cases of childhood leukemia over a 15-year period was unusual for a population like this. 

In December 1979 the CDC asked the city of Woburn for permission to investigate the possible leukemia cluster. Jonathan Harr described the planning of the study as follows:

"With help from the Massachusetts Department of Health, an epidemiologist from Atlanta began designing a study for Woburn. Trained researchers from the department of health would be sent to the homes of the twelve families with leukemic children and conduct in-depth interviews on a wide range of subjects. The researchers would also interview twenty-four other Woburn families that had been selected as controls, matched by age and sex with the leukemic families. The study, said the experts, would take a year to complete."

from A Civil Action by Jonathan Harr, Vintage Books, 1996

 spacerToggle open/close quiz question

What kind of epidemiologic study was this?

 spacerToggle open/close quiz question

Why did the investigators choose this particular study design?

 spacerToggle open/close quiz question

Why did the investigators enroll 24 control families?