PROPOSED EMERGENCY EXPOSURE LIMITS FOR MONOMETHYLHYDRAZINE
Final rept. Nov 1967-Oct 1968
SYSTEMED CORP NEWPORT BEACH CA
Pagination or Media Count:
Current EEL values for monomethylhydrazine MMH, a rocket propellant, have been based on minimal information consisting primarily of acute effects. The acute effects of MMH are seen only at lethal or supralethal dose levels and consequently a series of experiments were conducted to define an atmospheric concentration of MMH which would produce no irreversible injury and no clinical evidence of central nervous system CNS injury. Dogs, monkeys, rats and mice were exposed to MMH vapors for periods of 15, 30, and 60 minutes to concentration x time CT doses of 900 ppm-minutes. The 900 ppm-minute CT dose of MMH, which was 25 of the LC concentration for the most susceptible animal species tested, included a safety margin below the lowest dose reported to produce marginal decrement of performance in trained cats and monkeys. In view of the negative finding in all species exposed to the 900 ppm-minute CT dose level of MMH, we recommend an upward revision of current emergency exposure limits EEL values.