Excessive lead absorption resulting from exposure to lead naphthenate.

There are no reported studies of the relationship between exposure to lead naphthenate and lead absorption in humans. In an aluminum forging operation where lead naphthenate was sprayed without local ventilation, the mean concentration of lead in air was 96 micrograms/m3 with a range of 12-430 micrograms/m3. The 29 forge operators who worked in this area had a mean blood lead concentration of 63 micrograms/dl, which was statistically significantly (P less than .001) higher than the mean blood lead concentration of 17 micrograms/dl among the 103 unexposed workers. Similarly, the mean zinc protoporphyrin concentration among the forge operators was 265 micrograms/dl, which was statistically significantly (P less than .001) higher than the mean concentration of 26 microgram/dl among the unexposed workers. Nineteen workers, all of whom worked in the forge areas, had blood lead concentrations in excess of 60 micrograms/dl, with the highest concentration being 108 micrograms/dl. This is the first reported instance in which the use of lead naphthenate has been associated with increased lead absorption in humans.