Cancer incidence among alachlor manufacturing workers.
A historical cohort study was conducted to evaluate cancer incidence among chemical workers with occupational and environmental exposure to alachlor, the active ingredient in a family of pre-emergent acetanilide herbicides. The study followed 943 workers with at least 1 year of cumulative employment at the Monsanto plant in Muscatine, Iowa, from startup of the alachlor manufacturing process in March 1968 through December 1990. Approximately 96% of all workers were successfully traced to determine their last known residence and cancer status. Eighteen workers were diagnosed with cancer during the follow-up period, based on pathology information from the statewide cancer registry maintained by the State Health Registry of Iowa. The standardized incidence ratio for all cancers was 1.5 (95% CI 0.9-2.4) for all workers exposed to alachlor, which was due primarily to elevated rates for colorectal cancer and chronic myeloid leukemia. Workers with 5 or more years in estimated high alachlor exposure jobs had elevated rates of colorectal cancer (3 cases, SIR = 5.2, 95% CI 1.1-15.1). Interpretation of the study results is limited by the small size of the study population, minimal length of follow-up, and current information concerning alachlor metabolism in primates and humans. Nonetheless, the findings suggest the need for continued evaluation of this and other alachlor-exposed cohorts.
Leet
T
T
Department of Epidemiology, Seattle, University of Washington, USA.
Acquavella
J
J
Lynch
C
C
Anne
M
M
Weiss
N S
NS
Vaughan
T
T
Checkoway
H
H
D000081:Acetamides / Q000009:adverse effects*; D000328:Adult; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006540:Herbicides / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D007484:Iowa / Q000453:epidemiology; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000139:chemically induced / Q000453:epidemiology; D008297:Male; D009369:Neoplasms / Q000139:chemically induced* / Q000453:epidemiology; D009784:Occupational Diseases / Q000139:chemically induced* / Q000453:epidemiology; D016273:Occupational Exposure; D016017:Odds Ratio; D012042:Registries; D012189:Retrospective Studies; D013997:Time Factors; D014881:Water Supply
D000081:Acetamides; D006540:Herbicides; C000188:alachlor