The earliest record I could find was a plumbing permit from 1931. The company was called Pantorium Dye Works and they operated as a Laundry and (later) as a Dry Cleaner. The original building was burned in a fire and they built the current concrete building in 1931. Right now, there is no basement, but I have to imagine there was one in the original building.
Our building seems to be a descendent of the Seattle Pantorium Dye Works, Inc., in which there is a famous building of the namesake in Seattle. Ironically, there is another company that was started in Chicago in 1919 called Pantorium Dye Works. They are still around today! I sent an email to them to see if they were related and got a call immediately from the president of the company - a fourth generation owner whose great grandfather had started the company in 1919.
He relayed to me the history of the name Pantorium. He said that his great grandfather wanted to come up for a name for his company that would stick in people's minds. He thought that in school, when you went to listen to the teacher you went to the Auditorium, so when you go to get your pants cleaned you go to the Pantorium.
The only problem is that he started his company in 1919 and there are records of the Seattle Pantorium going back to 1912. I still like the story though. He is a very proud fourth generation owner.
The reason why I was so interested in the name is because it's etched in tile out our front door. So now we know Pantorium = Pants + Auditorium.