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Ask Lyn: Green Rivers for St. Patty’s Day?

Tuesday, February 23, 2021

TWF Posted by: TWF

Dear Lyn,

With St. Patty’s Day approaching, I’ve been wondering: how do they turn the Chicago River green? And is it bad for the river?


Green With Curiosity

Photo Credit: Wikimedia Commons

Dear Green with Curiosity,

Interesting question! The river-dyeing tradition itself has been around since 1962. It actually sprang from Mayor Richard J. Daley’s efforts to identify sources of pollution (sewage, in fact!) in the river. To help spot the pollution, Daley authorized the use of an oil-based fluorescein green dye, and that’s when a member of the Chicago Journeyman Plumbers Local got the idea to turn the whole river green for St. Patrick’s Day.

Environmentalists argued the original dye actually was harming the already compromised river, so in 1966, the Journeyman Plumbers Local, organizers of the annual St. Patty’s Day event, developed an alternative: a vegetable-based powder whose formula is top-secret. The dry powder is orange, but when it mixes with water, it turns the river bright green for several hours. The organizers claim the powder is completely safe, and environmentalists don’t disagree.

However, as the health of the river has improved over the years, some groups are more concerned about the message the tradition sends: maybe turning the river green suggests the river is not actually a healthy, living, important ecosystem that should be respected. What do you think?

If you want to learn more, check out the links above!

Happy St. Patty’s Day,