| Answer | Crossword Clue |
|---|---|
| OZONE | Blue gas |
| OZONE | Blue gas. |
| OZONE | Pale blue gas |
| OZONE | Pale-blue gas |
| OZONE | Noted pale-blue gas |
| OZO | Combining form for a blue gas. |
| OZONE | Blue gas in the greenhouse effect |
| ESSO | Gas brand whose logo has a blue oval |
| ESSO | Red-letters-in-a-blue-oval gas logo |
| EXXON | Gas brand with a red-white-and-blue logo |
