It comes from the law of Ex:

- avoid it

- do not ignite it

- if it happens, have it under control

Which means:

- no Ex atmosphere

- Ex protection applied

- your last chance

If all or any of them applied:

- you and your mates stay home even tonight

- your insurance co. may have no reasons not to pay if anything still happens

- ...

Ex is expensive, but best interest of all involved.

Ex personnel competency here in this case is not a piece of paper, which we shall immediately put onto wall.

But it has the meaning all have the same understanding of Ex: it shall be first Ex, then functional.

Keep up good work!

#ExAM