range 15-30 JLg Pb/100ml blood). This small difference is remarkable from the toxicological standpoint. The key concept here is control of dis­ persal. The industrial actions of man bring contact with a wide variety of substances, some of which are poisonous or dangerous. In such cases pro­ tective measures are taken to keep hazardous exposure to a minimum. In the of lead compounds, stringent regulations are production and distribution enforced. The exception to this is in the dispersal of lead from vehicle exhausts following purchase from the petrol pump. Perhaps man's long­ standing acquaintance with lead in home and industry is responsible for a complacency which until only recently has been unquestioned. Beginning in the late 1960s, evidence began to accumulate suggesting that lead at relatively low levels of exposure might be causing negative effects on neurobiological function.