Original: Another deadly effect of napalm B, primarily in its use in firebombs, is that napalm "rapidly deoxygenates the available air" and it also releases large amounts of deadly carbon monoxide.
Simplified: This is done by mixing different of amounts of napalm and other materials. Another useful (and dangerous) effect, primarily involving its use in bombs, was that napalm "rapidly deoxygenates the available air".