Respiratory and skin effects of exposure to wood dust from the rubber tree Hevea brasiliensis.

OBJECTIVES: Potential health effects related to wood dust from the rubber tree, which produces natural rubber latex, have not been previously investigated. The main aim of this study was to investigate the relations of rubber tree dust exposure to respiratory and skin symptoms, asthma and lung function. METHODS: A cross-sectional study was conducted among 103 workers (response rate 89%) in a rubber tree furniture factory and 76 office workers (73%) in four factories in Thailand. All participants answered a questionnaire and performed spirometry. Inhalable dust levels were measured in different work areas. RESULTS: Factory workers showed increased risk of wheezing, nasal symptoms and asthma compared to office workers. There was a dose-dependent increase in wheeze and skin symptoms in relation to dust level. Significantly increased risks of nasal symptoms (adj OR 3.67, 95% CI 1.45 to 9.28) and asthma (8.41, 1.06 to 66.60) were detected in the low exposure category. Workers exposed to ethyl cyanoacrylate glue had significantly increased risk of cough, breathlessness and nasal symptoms. There was dose-dependent reduction in spirometric lung function with wood dust level. CONCLUSIONS: This study provides new evidence that workers exposed to wood dust from the rubber tree experience increased risk of nasal symptoms, wheeze, asthma and skin symptoms and have reduced spirometric lung function. Exposure to cyanoacrylate is related to significantly increased respiratory symptoms. Results suggest that the furniture industry using rubber tree wood should implement appropriate exposure control measures to reduce wood dust exposure and cyanoacrylate glue exposure to protect their employees.

Respiratory effects of occupational exposures in a milk powder factory.

Ingestion of milk powder is a known cause of allergies in children, but the risks to respiratory health from exposure to inhaled milk powder have not been studied previously. The aim of the present study was to assess the effects of occupational exposures in a milk powder factory on respiratory symptoms and lung function. A cross-sectional study was conducted on 167 milk powder factory workers (response rate 77%) and 76 office workers (73%) from four factories in Thailand. All participants answered a questionnaire and performed spirometry. Measurements of concentrations of dust were used to give additional information on exposures. Mean respirable dust concentrations in the factory were 0.02-2.18 mg x m(-3). The risk of breathlessness and nasal symptoms were significantly increased in production and packing staff. The risk of skin symptoms was significantly increased in those adding vitamin mixture to milk powder. Factory workers showed significantly lower forced expiratory volume in one second measured as percentage of predicted value. The present study provides new evidence that workers exposed to milk powder by inhalation are at an increased risk of nasal symptoms, wheezing and breathlessness, and exhibit reduced spirometric lung function, even at relatively low air concentrations of milk dust.

An in vitro comparison of the permeation of chemicals in vapor and liquid phase through pig skin.

This study used pig skin to compare vapor and liquid permeation of benzene, n-butanol, and toluene in vitro. Vapors of radio-labeled chemicals were generated by passing purified air through two saturators in series containing the labeled chemical. The generated vapor was directed into the donor compartment of a modified liquid permeation cell. For liquid permeation experiments, neat chemicals were dosed directly on the surface of the skin. The variability of the generated concentrations for the vapor phase of each chemical ranged from 3-7%. The mean flux of the liquid chemicals was significantly higher than those of the vapor phase. There was no significant difference in the flux of the individual chemicals in the liquid phase. In the vapor phase test, the flux of toluene and benzene were not significantly different; however, for n-butanol the flux was significantly lower than the for either benzene or toluene.