Quote Originally Posted by mikey hulk
I thought it was 10ml air??
It depends on several factors (age, location, vessel integrity, rate of injection, etc).

An amount as little as 5ml/kg of air can induce effects similar to a stroke. In a vein, 100-300ml at a rate of 100ml/second will result in any number of cardiac events ranging severity up to death. If a gas/air embolism is injected into an arterial vessel, 0.5-5ml of air can be fatal.