1.   Filled with explosive hydrogen, it was just as deadly.

2.   In addition to the electrical short, Columbia also experienced a small leak of explosive hydrogen during its climb to orbit.

3.   Midway through the flight, shuttle engineers released photographic evidence of a small leak of explosive hydrogen fuel from the exhaust nozzle of the right engine.

4.   New airships, built with space-age materials and filled with inert helium rather than explosive hydrogen, are taking to the skies.

5.   Space agency experts made the photographs public last Sunday, saying the irregularity suggested a small leak of explosive hydrogen.

6.   The launching of the shuttle Columbia was postponed Thursday in the final hours of countdown, when potentially explosive hydrogen propellant leaked from a rocket engine valve.

7.   Space shuttle Columbia began leaking explosive hydrogen fuel just hours before liftoff, forcing NASA to postpone the science mission for a week.

8.   The chemical also can produce potentially explosive hydrogen gas when it comes in contact with water.