Iron Man, Vol. 1 #48A (1972)

The Fury And The Inferno
Tony Stark uses his controlling shares to reobtain control of Stark Industries and fire Simon Gilbert. As a result, Simon hires Firebrand to attack SI. While Iron Man and Firebrand fight, Simon tries to set a bomb in the plant, but the battle traps him under rubble with the detonator armed. Iron Man saves Firebrand's life, preventing him from reaching Simon Gilbert. Only after the (presumably fatal) explosion does Firebrand reveal that he is really Simon Gilbert's son.
Release Date: 1972