City of Fear (1959)

Vince, an escaped convict from San Quentin headed for Los Angeles, has a canister in his possession that he thinks has heroin inside of it. It does not; instead, it contains Cobalt-60, a dangerous nuclear substance with enough radiation to kill most of the population of Los Angeles. As continued exposure to the element is slowly killing Vince, authorities move to capture him and the canister.

Cast:
Vince Edwards as Vince Ryker
Lyle Talbot as Chief Jensen
John Archer as Lt. Mark Richards
Steven Ritch as Dr. John Wallace
Patricia Blair as June Marlowe
Kelly Thordsen as Detective Sgt. Hank Johnson
Joseph Mell as Eddie Crown