NIOSH Testimony on Velsicol Chemical Co., Leptophos, by B. F. Craft, December 13, 1977.
This testimony concerned experience of NIOSH in investigating leptophos (21609905), known by the trade name Phosvel. Potential problems among employees at the Velsicol Chemical Company in Bayport, Texas involved in the manufacturing and packaging of leptophos came to light in January of 1976 through the EPA. Reports of the chemical being neurotoxic to mammals and fowl were causing concern as applications were being made to increase its use in this country. A visit was made to this facility but no operations involving leptophos were witnessed at this time. Two of the 26 workers NIOSH examined had evidence of mild neurological dysfunction; 12 cases of serious neurological disorders had been previously identified. Because of a rapid turnover of workers, an attempt was made to medically study all present and former employees. A substantial number of workers reported that they had experienced one or more symptoms usually associated with exposure to organophosphates at some time during the preceding 5 year period. Of 155 workers examined, 63 had abnormalities in one or more of the objective tests or examinations. Eleven of the 63 had abnormal neurological examinations. Most of these also had abnormalities in nerve function, psychological tests or performance tests. NIOSH concluded that a substantial number of workers had neurological, electromyographic, electroneurographic, and psychological performance abnormalities. Due to the presence of other neurotoxic agents it was not possible to clearly establish a causal association of these findings with exposure to leptophos.