1.   A spark flew, igniting the gaseous oxygen in the tank.

2.   The walls of these are thick with blood vessels which absorb gaseous oxygen.

3.   This has walls thick with blood capillaries which absorb gaseous oxygen.

4.   At launch, a series of ducts and fans built into the concrete pad are supposed to vent gaseous oxygen, hydrogen and water safely away from the vehicle.

5.   The discovery of gaseous oxygen on Europa was made by scientists using the Hubble Space Telescope.

6.   Engineers also had to contend briefly with higher-than-normal levels of gaseous oxygen in the shuttle.