Watch: Chicago River goes green for famed St. Patrick's Day celebration
CHICAGO - Thousands of green-clad spectators gathered in downtown Chicago Saturday for the city's grand annual St. Patrick's Day celebration.
Plumbers Local 130 dyed the Chicago River a brilliant emerald green, while other boats followed to mix it in. People on the mixing boats are sponsors who paid to be there.
The Chicago tradition dates back to 1962, when local union members who were using green dye to help identify leaky pipes decided to dump 100 pounds of the dye into the river. The dye stayed there for an entire week.
The event has been a fixture ever since and draws thousands to downtown Chicago rain or shine.
What's in the dye itself is a "closely guarded secret,' but it's harmless to wildlife and lasts for roughly five hours, FOX 32 reports.
St. Patrick's Day is Friday, March 17.