OBJECTIVE To explore a perceived unusual occurrence of glioblastoma at one jet engine manufacturing facility located in North Haven (NH), Connecticut (CT). METHODS Subjects were 212,513 workers ever employed in 1 of 8 manufacturing facilities from 1952 to 2001 and at risk from 1976 to 2004. We identified 722 cases of CNS neoplasms mainly by tracing through 19 state cancer registries. We computed standardized incidence ratios (SIRs) based on CT state and national rates and modeled internal relative risks (RRs). RESULTS We found overall deficits in cases for glioblastoma (275 cases, SIR = 0.77, CI = 0.68-0.87) and most other histology categories examined. NH workers had a not statistically significant overall 8% excess in glioblastoma (43 cases, SIR = 1.08, CI = 0.78-1.46). Salaried NH workers had a statistically significant twofold risk of glioblastoma compared with hourly workers (17 cases, RR = 2.04, CI = 1.15-3.57). Other subgroups of NH workers revealed elevated but not statistically significant glioblastoma risks but little evidence of an association with duration of employment or time since first employment. CONCLUSIONS Incidence rates for glioblastoma and other malignant CNS neoplasm histologies were not elevated in the total cohort. The glioblastoma excesses observed among NH workers may reflect external occupational factors, non-occupational factors or workplace factors unique to NH unmeasured in the current study.