From: Avengers #484 (Red Zone part 4 of 5)
The Red Skull has infiltrated the US Government and released a biological weapon in the form of a red mist at the base of Mount Rushmore. As the mist encroaches into nearby populated areas it kills everyone in its path and it’s up to the Avengers to stop him!
It’s a fairly basic story, bad guy intent on mass murder and the good guys have to stop him. It’s a good read with the highlight of Black Panther laying some serious smack down by brutally beating down the Skull and viciously breaking his jaw.