Health hazard evaluation report, HETA-98-0069-2774, UniSea, Inc. , Dutch Harbor, Alaska.
On December 19, 1997, the National Institute for Occupational Safety and Health (NIOSH) received a request for a health hazard evaluation (HHE) from the management of the UniSea shore-based crab processing facility in Dutch Harbor, Alaska. They were concerned about respiratory illness among workers including bronchitis and asthma. The NIOSH study consisted of early-season and late-season medical and environmental surveys during the 1998 opilio snow crab season. The objectives of this investigation were to understand the nature of respiratory illness observed in crab processing workers, to identify areas and sources of exposure, to identify any relationships between crab processing exposures and respiratory health outcomes, and to develop strategies to prevent illness in crab-processing workers. The two surveys included a symptoms questionnaire, lung function testing, and blood collection. The environmental evaluation consisted of air sampling for aerosolized protein, crab allergens, endotoxin and microscopic analysis of materials splashed on workers and breathed by workers. An over-all participation rate of 76% of workers was attained for completion of both the early and late-season questionnaires. At the early-season survey, five individuals noted a previous doctor-diagnosis of asthma. Over the course of the season, one of the participants with a previous doctor-diagnosis of asthma experienced significant work-related worsening of asthma. In addition, one individual working in crab processing and one individual engaged in related activities acquired a new doctor-diagnosis of asthma during the season. In this investigation, combination of symptoms were used to define specific health outcomes. The percent incidence of new cases of the upper respiratory outcome was 56%; of the asthma-like outcome 26%; and of the bronchitic outcome 19%. Workers with a positive family history of allergies or working in the butchering area had significantly increased risk for development of the upper respiratory outcome. For the asthma-like outcome, male gender, family history of allergies, elevated ECP (a protein in the blood indicating eosinophilic inflammation), butchering activities and degilling activities were risk factors significantly related with the outcome. For the bronchitic outcome, significant association was found among workers with age less than 35 years, male gender, elevated antibodies to crab (serum anti-kanimiso IgE and anti-Pagurus crab IgE,) elevated serum ECP and the task of degilling. Although this investigation was limited due to the relatively small size of this population, data showed development of new respiratory symptoms and asthma among crab processing workers over the six weeks of crab processing. These problems appeared to be occupationally related. Higher prevalence of IgE-sensitization to crab among new or "naive" workers suggests that workers susceptible to respiratory illness related to crab processing may be more likely to leave their job ("healthy worker effect"). In part because the precise etiological agent causing respiratory symptoms was not fully characterized, exposure assessment did not allow evaluation of dose-response relationships.
Allergies; Microscopy; Spirometry; Respiratory-infections; Respiratory-irritants; Lung-function; Pulmonary-system-disorders; Respiratory-system-disorders; Region-10; Hazards-Confirmed; Fishing-industry;
Author Keywords: Crab related work; asthma; allergy; crab; sea food; IgE; microscopy; spirometry; environmental assessment