 Mr. Burns ' drilling operation causes further harm and distress to many Springfield citizens : Moe 's Tavern is closed due to the harmful fumes from the drilling , leaving Moe and Barney enraged ; the drilling wrecks the Springfield Retirement Castle , leaving Grampa homeless , forcing him to move in with the Simpsons ; and Bart 's treehouse is destroyed by a burst of oil from the rig , which also injures Santa 's Little Helper . 
