This weak point in the wiring also ran near a junction in an ethylene glycol/water cooling line that had been prone to leaks. The electrolysis of ethylene glycol solution with the silver anode was discovered at the Manned Spacecraft Center on May 29, 1967, to be a hazard capable of causing a violent exothermic reaction, igniting the ethylene glycol mixture in the Command Module's pure oxygen atmosphere. Experiments at the Illinois Institute of Technology confirmed the hazard existed for silver-plated wires, but not for copper-only or nickel-plated copper. In July, ASPO directed both North American and Grumman to ensure no silver or silver-coated electrical contacts existed in the vicinity of possible glycol spills in the Apollo spacecraft.