Related Clues:
- Simple hydrocarbon
- Colorless, odorless gas used as fuel
- Natural gas product
- Alternative to coals
- Barbecue gas
- Odorless fuel gas
- Refrigerant ingredient
- Marsh gas
- Biofuel option
- Colorless, odorless alkane
- Marsh gas, mostly
- Colorless, odorless gas
- Dangerous buildup in a mine
- Gas in fuel mixtures
- Hot-air balloon fuel