The Fall of Metropolis continues in Adventures of Superman 514 (July 1994), by Karl Kesel, Peter Krause and Ron McCain.
There is a hallucination causing haze permeating the air, driving people into a murderous frenzy. Superman believes himself immune, but soon succumbs to it as well.
Emil Hamilton finds the cure, but risks his life to reach Superman, getting seriously wounded in the arm. Superman manages to overcome the effects of the gas on his own, by facing and accepting his fears, but Hamilton’s cure works on those not so strong.
It does, however, cost him his arm, which gets amputated. Hamilton also recognizes the gas, as one created by Lexcorp for the military.
The story continues in the next issue of Action.