After Homer accidentally pollutes the town's water supply, Springfield is encased in a gigantic dome by the EPA and the Simpsons are declared fugitives.
Dan Castellaneta
as Homer Simpson / Itchy / Barney / Abe Simpson / Stage Manager / Krusty the Clown / Mayor Quimby / Mayor's Aide / Multi-Eyed Squirrel / Panicky Man / Sideshow Mel / Mr. Teeny / EPA Official / Kissing Cop / Bear / Boy on Phone / NSA Worker / Officer / Santa's Little Helper / Squeaky-Voiced Teen (voice)
Julie Kavner
as Marge Simpson / Selma Bouvier / Patty Bouvier (voice)
Nancy Cartwright
as Bart Simpson / Maggie Simpson / Ralph / Nelson / Todd Flanders / TV Daughter / Woman on Phone (voice)
Yeardley Smith
as Lisa Simpson (voice)
Hank Azaria
as Professor Frink / Comic Book Guy / Moe / Chief Wiggum / Lou / Carl / Cletus / Bumblebee Man / Male EPA Worker / Dome Depot Announcer / Kissing Cop / Carnival Barker / Counter Man / Apu / Drederick Tatum / Sea Captain / EPA Passenger / Robot / Dr. Nick / Wise Guy (voice)
Harry Shearer
as Scratchy / Mr. Burns / Rev. Lovejoy / Ned Flanders / Lenny / Skull / President Arnold Schwarzenegger / Kent Brockman / Principal Skinner / Dr. Hibbert / Smithers / Toll Booth Man / Guard / Otto / Kang (voice)
Pamela Hayden
as Milhouse Van Houten / Jimbo Jones / Rod Flanders (voice)
Tress MacNeille
as Sweet Old Lady / Colin / Mrs. Skinner / Nelson's Mother / Pig / Cat Lady / Female EPA Worker / G.P.S. Woman / Cookie Kwan / Lindsey Naegle / TV Son / Medicine Woman / Girl on Phone (voice)
Albert Brooks
as Russ Cargill (voice)
Karl Wiedergott
as Man / EPA Driver (voice)
Marcia Wallace
as Edna Krabappel (voice)
Russi Taylor
as Martin Prince (voice)