Tens of thousands of people lined the Chicago River on what began as a bitterly cold St. Patrick’s Day morning. Within an hour, the sun was shining and the river had been dyed a vibrant green to celebrate the fifth century patron Saint of Ireland, St. Patrick, on the day of his death.
Every year since 1963, volunteers have ridden up and down the river, dyeing the river green to celebrate St. Patrick’s Day. A parade, which begins at Balbo Drive and Columbus Drive, takes place at noon. The river dyeing and parade always occur on a Saturday, according to the parade website.
In the 1950s, Plumbers Local 130, a plumbers union, was asked by the mayor to help organize the parade and bring it from the West Side of Chicago to downtown, according to union spokesperson Sally Daly. One day, the union’s business manager encountered some plumbers with a green color on their overalls. They found the cause to be a substance used to test for leaks, and eventually became the basis of the green dye formula, or so the story goes, Daly said.
The formula is one of Chicago’s best-kept secrets, having stood the test of time and endless pursuit for 55 years.
“We’re not going to tell you,” Tom Rowan said to the Chicago Tribune in 2015. Rowan and his family have been part of the river-dyeing team since its inception. “They’ve been trying for years.”
The secret won’t be getting out any time soon, either.
“It’s a special tradition that they’ve maintained … it keeps the magic of St. Patrick’s Day in Chicago,” Daly said.
What they will and have told the public, however, is the formula has a vegetable base and is supposedly safe for use in the river, the Chicago Tribune reported. The formula, which at first looks like orange powder, is sprayed into the river from one boat as other boats follow behind, mixing it up. The color turns green once the powder hits the water. Approximately 40 pounds of dye is used over the course of the day, according to Daly.
“No one is sure what is in the dye that goes in the river,” John Quail said. Quail is the director of watershed planning with Friends of the Chicago River, an organization dedicated to improving the health of the Chicago River. “That’s been an issue … We haven’t done anything like FOIA requests to push the issue because we know it’s a historic tradition.”
Friends of the Chicago River tolerates the tradition but would like to see a change in how the river is turned green, such as using green lights, which would help people see the river as a natural resource, as well as a civic resource, Quail said.
“Right now the quality is good enough for people to swim in, which surprises people,” Quail said. “We have a mayor right now that sees the value of the river. There’s a lot of momentum around making the riverbank more natural and seeing its value.”
This year, organizers extended the river dyeing one block west to State Street. The river was dyed between Columbus Drive and Wabash Avenue in previous years. The move addressed the event’s popularity by allowing more spectators — some of who come from out of state — to watch the dyeing process.
Brady Lessener, a 49-year-old Milwaukee resident celebrating St. Patrick’s Day in Chicago for the first time, came dressed to impress in a novelty leprechaun suit.
“What a ball,” Lessener said. “The crowd is great and I’ve never seen the river dyed like that. It’s going to be a great day.”
The river-dyeing tradition has been a part of Loyola student and Aurora native Alexis McDaniel’s life since childhood.
“I remember being excited to watch the river change color when I was younger, so I think it’s a great Chicago tradition,” McDaniel, 21, said. “I also appreciate that the dye is safe and nontoxic to the river, but still so vibrant and cool to see.”
A previous version of this article stated Saint Patrick was a 17th century saint. It has been corrected to fifth century.