How Chicago Plumbers Turn the City’s River Green? - Parker & Sons

If you happened to find yourself in Chicago last month, on the 18th of March, you would have found yourself confronting a rather strange and shocking phenomenon. The Chicago river had turned green! Had some strange algae started growing at the mouth of Lake Michigan? Had some ecological disaster struck? Should you be worried?! No. No, no no no no. It was just Saint Patrick’s day, silly! Every year, as a celebration of Chicago’s rich Irish heritage, the Chicago Plumber’s Union turns the Chicago River green. How long has this been going on for, and how exactly do they pull this off?

The Chicago River was dyed green for the first time on Saint Patrick’s Day 1962. Mayor Richard J. Daley is widely credited with coming up with the idea of dyeing a body of water green, although most say he was more focused on Lake Michigan. Stephen M. Bailey eventually suggested it would be easier to turn the Chicago River green, and it was Plumber’s Union Local 130 the provided the means. They had been working with a dye used to detect leaks which had the uncanny ability to turn the water a vibrant shade of green.

Local 130 has been handling the Saint Patrick’s Day tradition ever since. Exactly what is in the amazing dye is a closely guarded secret although Pat McCarthy, parade coordinator with the Plumber’s Union has said that, “It’s very environmentally safe.”

One of the strangest characteristics of the dye which is commonly referred to as “leprechaun dust,” is that is not in fact green, but rather a brilliant shade of orange! The dyeing occurs between Columbus Driver and Wabash Avenue and usually lasts for several days. The process begins at 9 A.M. with spectators gathering much earlier to observe the incredible transformation.

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