Verb(s) needed

[Nordic Bill]

I was wondering how to translate this part of a ferry's safety features which are posted in all the cabins of the ship for passenger orientation.

It's in relation to onboard fires, advising people to keep low. Which verb would be best suited here?:

"Smoke always _______________________ last at floor-level."

My bets are on accumulates, gathers and collects.

Any help is appreciated.

Thanks.

Bill

[Casiopea]

What about?

EX: Keep as low to the ground as possible. Smoke accumulates last at floor-level.

[Nordic Bill]

Sounds great to me! Thanks very much!

(I'll use floor rather than ground in this case, since this relates to ferry evacuations).