Dex cool was not the issue, poor seals in GM intake manifolds were the problem. The reaction with air and dex cool was the problem. Ford has been using the orange stuff since at least 09 in the F150s without issue. Dex cool is readily available in 50/50 pre mix and is safe to use in your Focus.
2012 Focus SE 5MT, ingot silver metallic. Window tint, focal wheels, lots of chrome bits.