Seven-year follow-up of workers exposed to 1,2-dibromo-3-chloropropane.

A follow-up report was done of workers exposed to 1,2-dibromo-3-chloropropane (DBCP) 7 years after termination of exposure. A 1977 study of male pesticide workers exposed to DBCP in a California agricultural chemical plant identified many who were azoospermic or oligospermic. Sperm concentration and serum follicle-stimulating hormone (FSH) levels in 44 of these workers were reassessed 5 to 8 years after exposure was terminated in 1977. Two of the eight originally azoospermic workers produced sperm during the follow-up, although only one had normal sperm counts. No increase in sperm production could be detected in men who had low sperm counts in 1977, and elevated serum FSH levels did not drop in oligospermic or azoospermic men. These results suggest that permanent destruction of germinal epithelium occurs in most DBCP-sterile persons.