The gas was drifting.

Some gas drifted toward the long lines at nearby food distribution points.

City Evacuated Most of the city was evacuated this afternoon because of concern that toxic gases from the explosion might drift through Henderson.

The quarters were all the way across the compound and the wind was usually from the northwest, which meant that gas might be drifting between him and the masks.

His eyes widened - then closed, as the instant sleeping gas from the crunched vial in the cigar drifted into his hairy nostrils.

This allowed a useful amount of gas to be released but there was danger that the wind would change and the gas would drift back over the attacking troops.

Being heavier than air, the gas crept across no man's land and drifted into the British trenches.

The gas drifted back, and stung their eyes.

Unlike liquids, heavier gases did not drift to the bottom upon mixing.

As it turned out, he was frequently gassed (the tear gas usually drifted into the stand, anyhow) but seldom clubbed.