A Study of the Concentrations of Polycyclic Aromatic Hydrocarbons in Gas Works Retort Houses.

Measurements of the concentration of 3:4-benzpyrene and other polycyclic aromatic hydrocarbons have been made in gas works retort houses of several types. The tarry fumes which escaped from retorts contained extremely high concentrations of polycyclic hydrocarbons, but in general men were only exposed to these very briefly. The mean concentration of 3 :4-benzpyrene determined from long-period samples at sites representative of normal working conditions in three works was 3 ,ug./m.3, over 100 times the normal level in the City of London. Above the retorts in an old horizontal retort house the concentration was over 200 ,ug./m.3, about 10,000 times that in the City, and the 'top-man' working there could be exposed to this in the normal course of his duty. We found no working areas in the vertical retort houses where men could be exposed to such massive concentrations of polycyclic hydrocarbons. Apart from defining these special conditions above horizontal retorts our results did not reveal any gross differences in pollution of the general air in horizontal and continuous vertical retort houses.