How Do They Dye the River Green in Chicago for St. Patrick’s Day?

The tradition of dyeing the Chicago River green was postponed due to coronavirus concerns, along with Chicago’s other St. Patrick’s Day festivities. However, a portion of the river turned green anyway, despite the sanctioned dyeing cancellation.

How the river turned green is a mystery. However, a plumber’s union in Chicago is claiming responsibility.

The river is typically dyed green by a retired police officer. The river has been dyed every year since 1962, and for reasons that aren’t quite clear, it continued for another year despite the thwarted plans due to the novel coronavirus, or COVID-19.

The specifics behind what is used to dye the Chicago River green is a secret, but some of the methods aren’t kept as close to the vest.

Here’s what you need to know:

Chicago Local Plumbers 130 Said They Dyed the Chicago River Green Even After St. Patrick’s Day Events Were Canceled

A plumber’s union in Chicago is claiming they are responsible for dyeing the Chicago River green. All three of Chicago’s St. Patrick’s Day parades were postponed due to the novel coronavirus, or COVID-19. Along with those cancellations was a decision not to dye the Chicago River green, which has been a St. Patrick’s Day tradition since 1962, according to WTTW.

The decision to delay the downtown Chicago St. Patrick’s Day parade, dyeing of the Chicago River, South Side Irish Parade and Northwest Side Irish parade was made out of an abundance of caution, Mayor Lori Lightfoot told the news station Wednesday morning. No details were provided about when the events would be rescheduled, but they plan to hold the events at a later date.

However, over the weekend, a portion of the river mysteriously turned green.

“The North Branch of the waterway, upstream from the river’s junction with the North Shore Channel, flowed a distinctive shade of emerald on Saturday, treating residents of neighborhoods like Albany Park and North Park to a St. Paddy’s Day surprise,” the news station reported. “Who and how remains a mystery. Could have been the work of leprechauns but theories on social media pointed to rogue plumbers as the more likely potential culprits.”

According the the plumber’s union’s website, they claim they have been dying the river green for decades. However, this conflicts with other reports, which attribute the dye job to a retired police officer. The plumbers union said it uses a dye used to detect leaks in dying the river.

The union scheduled its dyeing activities at 9 a.m. Saturday, March 14, 2020.

A Retired Police Officer Uses a Dye Used to Detect Leaks to Turn the Chicago River Green

Tom Rowan, a 76-year-old retired police officer, has been dyeing the Chicago River green since 1962, according to CNN. How exactly he dyes the river is a closely guard secret, the news station reported. However, he said he uses an orange substance, which is used to detect leaks. When it interacts with the river water, the water turns green.

Rowan’s father, Tom Sr., was a police officer assigned to patrol the river on boats. He was first assigned the task of dyeing the river in 1962, along with his colleague Michael Butler. The men brought his two teenage sons. The task became a family tradition, and every year, the dye crew has been “exclusively the two families,” CNN reported.

They call the orange powder used to dye the river “leprechaun dust.” It is derived from an environmentally-friendly vegetable base, the news outlet reported.

When asked exactly what the dye was made of, he told CNN, “It’s like the Coca Cola recipe — we don’t tell anyone.”

They disperse 40 pounds of the dye into the river to dye it green. To do so, they use a kitchen flour sifter. They use two boats, one to distribute the dye and the other to mix it. The second boat is called “The Mix Master.” Then, they go back and see if they missed any spots.

“One boat will do the dyeing and the other boat will do the mixing. You have to churn the water up,” Rowan said.