Did you know that it has been a tradition to dye the Chicago River green? In fact, the Chicago Journeymen Plumbers Local 130, or the Chicago Plumbers Union, have been dyeing the river since 1962. The process includes an orange, vegetable-based powder that is dumped into the river. The powder is spread by two motorboats (one for dumping, one for stirring the water). The dye is designed to be environmentally safe and does not pose a threat to the river’s ecosystem. We talk about that, AHR videos, thermal energy networks and much more.