| Answer | Crossword Clue |
|---|---|
| UFO | It may be produced by swamp gas |
| UFO | It could be created by swamp gas |
| EEK | Sound that may be produced by a mouse |
| DIN | It may be produced at a construction site |
| FUEL | It may be a gas |
| TANK | It may be full of gas |
| BOILER | It may be gas- or oil-fired |
| ENGINE | It may be gas-burning or hybrid |
| AIR | It may be free at the gas station |
