Editor,—We read with interest the article by Loughlin, Rothman, and Dreyer,1 and we write to provide the factual background for the study and additional information that may be of interest to your readers.

The study was commissioned by 17 chemical companies to defend against lawsuits we filed on them on behalf of 14 former students, who attended for two or three years (from 1943 to 1989) Port Neches-Groves High School and who contracted lymphohaematopoietic cancers (Hodgkin's disease, leukaemia, and non-Hodgkin's lymphoma).

Because of the study design, only four of the 14 cases we represent were counted in the study. Seven of the remaining 10 either still are alive or died after the cut off date for determining vital status. Two attended high school before 1963. And the remaining case died of “small cell carcinoma, unknown primary” (probably secondary to extensive chemotherapy treatment for Hodgkin's disease), but his death certificate did not mention Hodgkin's disease.

In addition to the cases we represent, we are aware of several other former students of the high school who died from lymphohaematopoietic cancers but were not counted because they attended school before 1963 (including at least four from Hodgkin's disease), and at least two others who have been diagnosed with lymphohaematopoietic cancers and are still alive.

The finding by Loughlin et al of increased mortality from lymphohaematopoietic cancer in men who attended Port Neches-Groves High School should come as no surprise. The worker populations at the adjacent styrene-butadiene rubber facilities have themselves been the subjects of epidemiological studies and have been found to have increased mortality rates for lymphohaematopoietic cancer.2 3 The styrene-butadiene rubber manufacturing complex in Port Neches was this country's largest emitter of butadiene, with ambient levels of butadiene outside the complex measured at up to almost 3 ppm as recently as 1990.4 It is little wonder that the children attending school next door would be similarly affected.

As noted by Loughlin et al, one weakness of their study was that they evaluated cancer mortality rather than incidence. To reflect the true magnitude of any increased risk of lymphohaematopoietic cancers and other cancers in that population, a morbidity study is needed and the cohort should be expanded to include those who attended the school at any time after the styrene-butadiene rubber facilities began operations in 1943.

Although we disagree with the authors' interpretation of the data, we are grateful to Loughlin et al, and the chemical companies who sponsored them, for undertaking this important project. We hope they will continue to follow up this cohort and give consideration to expanding the study along the lines we have suggested. In doing so they may create a model that can be used to study similar populations at risk outside the occupational setting.