A photo of the Chicago River dyed green.

Everybody loves to celebrate St Partrick’s day: dressing in green; drinking green beer; and ever since 1961, dyeing the Chicago River green. That was the year the city began enforcing water pollution controls and green dye was used as a tracer to confirm the sources of illegal discharge. The effect the fluorescent dye on the river was noticed and somebody had the idea to commemorate St...

Read More