Unexpected cause of raised benzene absorption in coke oven by-product workers.

BACKGROUND Urinary biological monitoring for benzene (by measuring benzene metabolites) in coke oven by-product workers produced the unexpected result that 2 out of 10 employees had significantly raised urinary S-phenylmercapturic acid (S-PMA). However, simultaneous personal air sampling showed no excessive airborne exposure. METHODS Possible causes for this finding were investigated having excluded inhalation as the route of uptake. It was suspected that skin absorption via contaminated overalls was the possible mechanism and a standard frequency for overall change was introduced. RESULTS Changing overalls after every four shifts reduced uptake levels to less than the equivalent of 1 ppm inhaled dose for all employees. CONCLUSION Skin absorption of benzene in coke oven by-product workers from contaminated overalls can be significant and therefore overalls should be changed on a regular and frequent basis.