feasibility the biological monitoring of workers exposed to benzene and toluene via measuring the parent compounds in the exhaled breath

background solvents such as benzene and toluene are commonly used in tire manufacturing, and significant occupational exposure to these chemicals adversely affects the health of workers. in biological monitoring, a complementary method for personal monitoring, the internal absorbed dose is measured and individual, environmental, and exposure differences are taken into consideration. conclusions the workplace conditions of tire factories must be improved. the biological exposure index can be calculated by determining the unchanged benzene and toluene concentrations in exhaled air; this can be used as a more reliable method for personal monitoring. results there were no significant differences between factories with respect to worker age or work history. personal exposure to benzene exceeded the current threshold limit value in 68% of workers. occupational exposure to benzene and toluene as external (i.e. in the breathing area) and internal doses (i.e. in the exhaled air) were significantly higher in factory b than factory a. in addition, the external and internal doses of both compounds were significantly correlated. materials and methods personal monitoring of 100 workers in tire factories a and b (n = 50 samples from each factory, n = 100 total personal samples) was performed using the national institute for occupational safety and health 1501 method. biological monitoring of the workers was performed by collecting exhaled air in tedlar® bags (n = 100). personal and biological samples were analyzed by a gas chromatograph equipped with a flame ionization detector. data were analyzed by independent t-test and correlation coefficients. objectives the present study evaluated external doses by personal monitoring and investigated a more practical approach to biological monitoring by measuring the internal doses of benzene and toluene in workers involved in tire manufacturing.