Possible Clues:

• Volume company supports, including article that’s hot stuff in it?
• Mount Etna, for instance
• Krakatoa or Vesuvius, eg
• Where you'd be lucky to find four leaves (-- er, no!) climbing conical hill
• On vocal (anag.)
• Lava emitter
• One is likely to blow one?s top on the radio to preserve order
• Book accountant required just after climbing mountain
• Mountain (could be a heavy smoker!)
• Performing on vocal my output is hot stuff