For more than forty years, revelers have dyed the Chicago River green for St. Patrick’s Day.
According to Green Chicago River, the tradition started in 1961 when a plumber was checking for leaks. He put a fluorescein dye through pipes in a building near the Chicago River. Fluorescein dye turns green in the water. It inspired the dyeing of the river for St. Patrick’s Day.
Normally, the Chicago River is a murky green, but the addition of the dye turns it an emerald green, reminiscent of Ireland, the Emerald Isle.
In 1966, complaints about the safety of the dye prompted a change in the dyes used. Now, forty pounds of vegetable dye turn the river green for four to five hours. The vegetable dye dissipates quickly with little effect on the environment, but don’t go swimming in the river.
This year, the river will turn green on Saturday, March 16 at 10 a.m.
The video below shows video and images of the annual St. Patrick’s Day dyeing of the Chicago River. The music is a tribute song by Superbad International.