How do St. Patrick’s Day parade sponsors transform a one-mile stretch of the Chicago River from unidentifiable blue-black to Irish Kelly green every year? It’s a secret. The formula involves 40 pounds of an orange powder, organizers told the Tribune before the March 11 parade. We asked local color-and-paint experts to take an educated guess at what the powder is:
– Allania Moore, market manager of a large paint company in Chicago: “Whatever this powder is could probably react with the enzymes and the acids in the water to create the color. I could fiddle around with some things, but I wouldn’t know exactly what they use.”
– Mark Lavelle, president, Calumet Paint and Wallpaper Inc. in Blue Island: “It must be something with like a food coloring that won’t pollute the river or hurt anything. It has to be non-toxic.”
– Jim Valukas, president, Accurate Dispersions Co., division of McWhirter Technologies (which makes paint components) in South Holland: “I would think it would be a food-grade dye. Because after anything we would put in the river, I’m pretty sure the EPA would want to have a long conversation with us.”
– Shelley Young, owner, the Chopping Block: “It’s probably just food coloring. They probably just get a vat of food coloring from a restaurant supply place.”
Those are all good guesses. The orange powder, which reacts with the water to turn green, is indeed a biodegradable food dye.
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Send inquiries to hlajewski@tribune.com
