Product of LC50 and the exposure time over which it was determined. NOTE 1 LCt50 is a measure of lethal toxic potency. NOTE 2 For fire effluent, the typical units are g. min. m-3. NOTE 3 For a toxic gas, typical units are . L. min. L-1 (T = 25 °C and P = 1 atm) - see volume fraction. See also: concentration, effective exposure dose, exposure dose and lethal exposure time