We live on the northern edge of Oak Creek 5 miles due south of Falk. Hubby heard the boom but didn't know what it was. I have friends at work who live just south of the viaduct and their windows and doors really rattled. I read where Falk will keep paying their employees until they can get regrouped. Thank Heaven for that. It's good that the viaduct wasn't damaged either. Traffic is heavy at that time of the morning with people going to work.
I saw before and after pics of this on the news tonite. It's weird, but the propane tanks are still there while the buildings were ruined.
It's so sad on what happened, but like you said, it could have been much worse if they hadn't started to evacuate before the explosion.

Kat