Related Clues:

• Ethane, e.g.
• Natural __
• Get off the stage
• Hydrogen or helium
• Fuel for a Fiero
• Oxygen or hydrogen
• Helium or radon
• Fab time
• 51 Across fuel
• Methane or ethane
• Lighted sign in a theater
• Get off or out
• It's often marked with a number
• Subject of a '70s shortage
• Station's supply