Henry Gibson (1935-2009) provided the voices of Barber, Mr. Bubble, Squirt and Gas Tank. He had a long career as an actor and comedian, appearing on television shows like Rowan and Martin's Laugh-In and Boston Legal, along with films like Nashville, The Blues Brothers and Magnolia.
Gibson also had an extensive voiceover career outside of Rugrats. He voiced Wilbur in the 1973 adaptation of Charlotte's Web. He voiced Mr. Stimpleton on another Klasky-Csupo cartoon, Rocket Power, and also appeared on The Grim Adventures of Billy and Mandy and King of the Hill, among other shows.