Occupational Exposure to Low Concentrations of Organic Solvents in Shipyards

Occupational Exposure to Low Concentrations of Organic Solvents in Shipyards: Hironobu Katsuyama, et al. Department of Public Health, Kawasaki Medical School—Because shipbuilders have to use organic solvents in very confined spaces, they have a higher risk of inhaling the solvents than workers working in an open space. The working environment at 14 workplaces with very limited space was examined and biological monitoring was performed on 18 workers who worked in such places. Out of 14 workplaces, only 4 did not exceed the assessment criterion. Although exhaust ventilation fans and chemical cartridge respirators were used to avoid exposure to solvent vapor irrespective of the concentrations of solvents, biological samples revealed inhalation of solvent vapor. Urinary excretion of hippuric acid and methylhippuric acid varied from 0.07 to 0.92 g/ g Cr and 0.02 to 0.42 g/g Cr at the end of the shift, respectively. Concentration of toluene and xylene in the end‐exhaled air varied from <0.1 to 5.0 ppm and <0.1 to 10.6 ppm, respectively. The concentration of metabolites in urine and the concentration of solvent in the end‐exhaled air revealed a strong correlation in the case of xylene but not toluene. Because of the limitation of space, the mean concentration of solvents in the working environment is not always available in shipyards, which make it difficult to estimate the amounts inhaled by workers. Biological monitoring of the end‐exhaled air provides useful information to make it possible to avoid continuous and/or unexpected exposure of workers who have to work in a very limited space.