For 60 years, the Chicago River has been dyed green every March in honor of St. Patrick’s Day. For a whole week, the river goes from an elegant aquamarine to a bold, beautiful green. But where did this tradition originate from and why did it stick for so long?
Our story begins way back in the year 1955. Richard J. Daley, the running mayor of Chicago, was facing a problem with the Chicago River: it was running rampant with waste. Daley tasked the plumber’s union to find the root of the problem. The plumbers used green dye to track the illegal waste. Daley saw the color of the river when it was dyed green and wanted to dye Chicago’s portion of Lake Michigan.
However, Stephen Bailey, business manager of the Chicago Plumbers Union, told Daley it was a bad idea to do that. Rather than dye the lake, Bailey told Daley to dye the Chicago River green, like how the river was dyed to detect the leaks. Then, in 1961, the river was dyed green for St. Patrick’s Day for the very first time.
In the modern day, the tradition is carried on by the Journeyman Plumbers Local 130 go out onto the river and use an, ironically, orange powder to dye the river green in the blink of an eye. Dyeing the river lasts around 45 minutes to an hour.
In the 1960s, the Chicago Plumbers Union used disodium salt to dye the river green. However, it was replaced because disodium salt increased the salinity of the water, thus making it a bit saltier and making it dangerous for people with low-sodium diets. In 1966, the city of Chicago changed its dye to a non-disclosed vegetable-based dye. It is unclear what it exactly is, but according to the EPA, “Illinois EPA found that at the concentration used in the Chicago River, it is completely non-toxic. … EPA contacted the Plumbers Unions on what was in the dye. Then, EPA’s toxicologist reviewed the dye’s ingredient and deemed it safe,” (Green, “Dyeing to be Green: The Chicago River and St. Patrick’s Day”).
Today, the city celebrates its Irish heritage with all the citizens of Chicago by dyeing its beloved Chicago River a bright emerald green for all to see. And as we continue to carry the tradition on, you should thank Richard Daley and Stephen Bailey for their contribution to this age-old tradition.