Nothing unusual. The initial call appears to come from a firefighter via his radio, then the first arriving company gives a size-up and asks for mutual aid. You can sense the urgency when they realize how advanced the fire is and its proximity to the ammonium nitrate storage.
I couldn't play the one off the link above but found several others. Here's a good one:
The most moving part for me was thinking about how these were the last words spoken by a couple of these guys.
More coverage on the other side of the site, FY.