 What was less clear was where to apportion responsibility.NASA engineers tended to point to what they saw as shoddy workmanship by North American Aviation.By contrast, North American executives blamed NASA management for its decision over their objections to pressurize the command module with pure oxygen to a pressure far in excess of that needed in space, in which almost any materialincluding Velcro, with which the cabin was filledwould instantly burst into flames if exposed to a spark.