#The cell phone had received at least two calls, which should have detonated several gallons of gasoline, but when the calls came in, the bomb failed to go off, the official said.

How do yo "detonate" several gallons of gasoline? You could detonate a gasoline-air mixture, otherwise the gasoline will just burn. (Like it did)

#Had it done so, that blast then would have ignited ..

So if the BOMB had gone of it would have ignited the propane tanks? So the propane tanks were not part of the initial bomb?

#... ignited six to eight tanks of propane in a mist to make a fuel-air explosion.

Ignited the propane tanks in a mist? But if they are already ignited, there shouldn't be any mist anymore because they are already buring.

It would be interesting to see the results of the investigations, but that article definetely isn't cutting it.