Can the flammability of ethyl alcohol be reduced?
Yes, usually simply by adding a non-flammable substance, typically water.
The best example of this is the proof test. It was found (by pirates, Aaaargh!), that rum, when diluted 50% by water, and placed over pile of gunpowder would not ignite the gunpowder when it burnt. Overproof rum, rum stronger than 50% by volume, would ignite the gunpowder. This was the "proof" of its concentration.