Flock workers' exposures and respiratory symptoms in five plants

Abstract

Background: Sentinel cases of lymphocytic bronchiolitis in flock production and coating operations triggered a five-plant study of airborne respirable dust and fiber exposures and health symptoms. Methods: Job histories from 219 current workers were linked to a job-exposure matrix derived from personal exposure measurements of respirable dust and fibers. Univariate group comparisons and multivariate modeling tested for relations between indices of cumulative and current exposure, and respiratory and systemic symptom outcomes. Results: Respiratory symptoms and repeated flu-like illnesses were associated with use of compressed air to clear equipment (blow-downs) and with respirable dust exposure (current and cumulative) after controlling for smoking. Blow-downs had an equal or greater effect than smoking status on most symptoms. Conclusions: Eliminating compressed air cleaning, engineering control of dust exposure, and respirators are needed to limit exposures to particulates. Longitudinal follow up may provide guidance for a dust or fiber level without adverse respiratory health effects.