Woburn, Massachusetts: The Cancer Cluster That Changed Environmental Law

Wells G and H — two municipal wells serving the east side of Woburn, Massachusetts — were found to be contaminated with trichloroethylene, tetrachloroethylene, and other industrial solvents when they were closed in 1979. The wells had been in use since 1964. For fifteen years, a portion of Woburn's population had been drinking water contaminated with compounds that are now classified as known or probable human carcinogens.

The contamination came from industrial sources: specifically, from the properties of W.R. Grace and Company and the Beatrice Foods Company, which had disposed of or spilled industrial solvents and chemical waste in ways that reached the aquifer feeding Wells G and H.

What made Woburn famous — and what made it the subject of Jonathan Harr's 1996 book "A Civil Action" and the film of the same name — was not primarily the contamination itself, but the extraordinary legal battle that followed a discovery of unusual medical significance: a cluster of childhood acute lymphocytic leukaemia cases in the east Woburn neighbourhood where Wells G and H had served the water supply.

The epidemiological study that established the Woburn leukaemia cluster as a real statistical event — and linked it to the Wells G and H contamination — was conducted by Jan Trichopoulos and colleagues from the Harvard School of Public Health.

Published in 1986, the study followed up on a case-control analysis of childhood ALL cases in Woburn between 1969 and 1979. It found: • A statistically significant cluster of childhood ALL on the east side of Woburn, in the area served by Wells G and H • A significant association between the estimated period of exposure to Wells G and H water during pregnancy and early life and childhood ALL risk • A dose-response pattern: longer exposure was associated with higher risk

The study was methodologically groundbreaking in one specific respect: it used a newly developed geographic methodology that modelled the mixing of water from different wells based on hydrological flow data, allowing estimation of how much of any household's water supply came from Wells G and H in each year between 1964 and 1979. This water exposure estimate was correlated with the residential histories of leukaemia cases and controls.

The five children The human context of the cluster was eight children from Woburn diagnosed with ALL between 1969 and 1979 — five of them from the east side neighbourhood served by the contaminated wells. Their families had organised years before the epidemiological study was completed, driven by the perception that something in their environment was causing their children's illness. Anne Anderson, whose son Jimmy died of leukaemia in 1981, was the central figure in the community's organisation and in the legal proceedings that followed.

The civil trial in Anderson v. W.R. Grace and Anderson v. Beatrice Foods — the "A Civil Action" case — produced one of the most complex and scientifically ambitious judicial proceedings in the history of environmental law.

The attorney Jan Schlichtmann, representing the Woburn families, faced a formidable challenge: to prove, in a court of law, that specific contamination from specific sources had caused specific cancers in specific children. This required not only establishing the contamination — which was factually clear — but establishing causation at the level of individual cases, across a causal chain that required linking solvent exposure to childhood leukaemia through mechanistic pathways that environmental science had not yet fully established.

The verdict and its limitations The jury found that W.R. Grace had contributed to the contamination of Wells G and H, but found for Beatrice Foods. The jury did not reach the second phase of the trial — the causation question — because the case settled with W.R. Grace before that phase was completed.

Schlichtmann's firm was financially destroyed by the litigation costs. The families received modest settlements. The legal question of whether the Wells G and H contamination caused the leukaemia cluster was never adjudicated to a final verdict.

W.R. Grace's subsequent Superfund liability Separate from the civil case, W.R. Grace was held responsible for Superfund cleanup costs at the Woburn site. The site's 15-year cleanup — involving soil and groundwater remediation — cost approximately $70 million, funded by W.R. Grace, the state of Massachusetts, and the EPA.

Woburn's legacy in environmental epidemiology and law operates primarily through the methodological and legal precedents it established rather than through its specific outcome.

The exposure assessment methodology The Woburn study's use of hydrological modelling to construct individual-level water exposure estimates — rather than simply categorising residents as "exposed" or "unexposed" based on address — became a methodological model for subsequent environmental contamination epidemiology. The approach is now standard in studies that need to estimate differential exposure within a contaminated community.

The community-initiated epidemiology model The Woburn families' role in driving the epidemiological investigation — connecting their physician to the Harvard researchers, funding preliminary analyses, and providing the case ascertainment that made the study possible — established a model for community-initiated environmental health research that has been replicated at contaminated sites across the US.

Organisations including Silent Spring Institute, the Health Impact Project, and university community-engaged research programmes have built on the Woburn model to conduct health studies at contaminated sites in response to community concern — filling the gap left when government agencies decline to investigate.

The limits of litigation Harr's book — while sympathetic to the families — is also an honest account of how the civil justice system failed to deliver the answers the Woburn families sought. The gap between the epidemiological evidence for a cluster associated with contaminated water and the legal standard of individual causation that civil litigation requires is one of the central tensions in environmental health law. That gap has not been closed; it remains as challenging for communities near contaminated sites today as it was for the Woburn families in the 1980s.