How long should it take you to done the protective mask and ensure an airtight?

From the time you hear, "Gas, gas, gas", see the signal or, god forbid, see your buddy drop, you have nine seconds to don and clear your mask.

This may seem like a short period of time but, with consistent practice I've seen it brought down to three or four seconds.

The faster you get the mask on the better your chance of living another day.