Respiratory Health of Foundry Workers Exposed to Binding Resin

Choi, Jung Keun; Rhee, Chang Ok; Paek, Do Myung; Choi, Byung Soon; Shin, Yong Chul; Chung, Ho Keun

Abstract

The effects of resin on the respiratory health have been investigated in 309 workers from four iron and steel foundries and the results compared with those from 122 workers who were not significantly exposed to resin gas and silica dust at the same industries. Phenol-formaldehyde resin was used in the core making and molding processes and workers were exposed to their decomposition products as well as to silica dist containing particulates The subjects were grouped according to formaldehyde, dust and other gas exposures, and smoking habits were considered also in the analysis. Standardized respiratory symptom questionnaire was administered by trained interviewers. Chest radiograph, pulmonary function tests, and methacholine challenge tests were done. Environmental measurements at the breathing zone were carried out to determine levels of formaldehyde, respirable dust and total dust. Foundry workers had a higher prevalence of symptoms of chronic bronchitis with chronic phlegm and chronic cough when exposed to dust. Exposure to gas was significantly associated with lowered FEV1 and obstructive pulmonary function changes. Exposure to formaldehyde and phenol gas was associated with wheezing symptom among workers, but FEV1 changes after methacholine challenge were not significantly different among different exposure groups. When asthma was defined as the presence of bronchial hyperreactivity with more than 20% decrease in FEV1 after methacholine challenge, 17 workers out of 222 tested had asthma. Fewer asthmatic workers were found among groups exposed to for maldehyde, gas and dust, which indicates a healthy worker effects in a cross-sectional study. The concentration of formaldehyde gas ranged from 0.24 to 0.43 ppm among studied foundries. The authors conclude that fornaldehyde and phenol gas from combust resin is probably the cause of asthmatic symptoms and also a selection force of those with higher bronchial reactivity away from exposures.