A Dallas apartment building has partially collapsed after firefighters were called to investigate a carbon monoxide leak. At least four firefighters were injured in the explosion. WATCH THE FULL EPISODE OF 'WORLD NEWS TONIGHT': https://bit.ly/3uHCDO5 WATCH OTHER FULL EPISODES OF WORLD NEWS TONIGHT: http://abc.go.com/shows/world-news-tonight WATCH WORLD NEWS TONIGHT ON HULU: https://bit.ly/3iQLwPp #WNT #Dallas #Explosion