Oxygen was 17 percent, and no noxious gases were indicated.

However, the fire could produce noxious gas which had to be removed.

The ugly smell of some noxious gas started to fill the air.

Many residents became ill, apparently from the noxious gases shortly after the impact.

Health problems associated with noxious gases are more common.

The problem was that this fact hung over every new meeting like a cloud of slightly noxious gas.

The creature exploded into noxious gas, but it had done its work.

This made for a great surface area of water, able to absorb over 90% of the noxious gas.

With the door open and the draft at work, the noxious gas was dissipated rapidly.

The air was full of noxious gases so he stopped breathing.