The purpose of the investigation was to assess the evidence of benzene poisoning in workers handling aeroplane dope and the rubber solvents used in covering self-sealing petrol tanks. These sub stances contain benzene in variable quantities. The amount depends on the supplies of xylene, toluene, benzene and other solvents available, though the amount of benzene in aeroplane dope, in spite of the difficulties of war conditions, does not exceed 15 per cent. In the case of the industrial rubber solvents the amount of aromatic hydrocarbons is not more than 5 per cent. H. J. Barrie visited six factories in Yorkshire. He interviewed and noted the age, number of children, length of time in present employment, type of previous occupation, and symptoms of 183 women and 53 men employed in dope shops. A similar number of workers of the same sex and economic group who were employed in the same factories, but who were not exposed to dope, were examined and used as controls. On each group he made full blood counts, and obtained samples of urine from each of the workers for the estimation of the inorganic-total sulphate ratio. J. F. Loutit and T. S. Marshall in Surrey made similar investi gations on a smaller scale in two factories. They examined 44 women and 21 men; but did not examine controls or collect urine samples, as no abnormality was apparent and they were engaged on other pressing work. D. Hunter and K. Perry also made investigations at eight factories in Hertfordshire on 164 women and 43 men using aeroplane dope, and 193 women using rubber sol vents, and examined a similar group of 174 women as controls. R. Milton obtained samples of urine from 100 women in factories, and from 100 women hospital patients as controls, and investigated the inorganic-total sulphate ratio. He also made investigations into the amount of benzene present in the atmosphere, both in the general shop and where specific jobs of short duration were being carried out, such as spraying the inside of cockpits and the under surface of wings in the horizontal position. Unfortunately, through circumstances beyond our control, the investigation of blood and concentration of benzene in the atmosphere did not coincide, and while the composition of the rubber solvent did not change, there is reason to believe that the amount of benzene in the dope was substantially less at the time of the atmosphere estimations than: that present at the time of the blood counts.