 The intensity of the fire fed by pure oxygen caused the pressure to rise to 29 psi ( 200 kPa ) , which ruptured the Command Module 's inner wall at 6 : 31 : 19 ( 23 : 31 : 19 GMT , initial phase of the fire ) . Flames and gases then rushed outside the Command Module through open access panels to two levels of the pad service structure . Intense heat , dense smoke , and ineffective gas masks designed for toxic fumes rather than heavy smoke hampered the ground crew 's attempts to rescue the men . There were fears the Command Module had exploded , or soon would , and that the fire might ignite the solid fuel rocket in the launch escape tower above the Command Module , which would have likely killed nearby ground personnel , and possibly have destroyed the pad . 
