There are at least 100 casualties being reported. A fire at a fertilizer plant in West Texas (West is the name of a small town 20 miles north of Waco in central Texas) was being fought by fire teams when it exploded, razing homes within 4 blocks and overcoming the emergency triage location.
There were emergency responders on the ground fighting this fire when that happened.
Listening to audio of the response, there may be more than 100 casualties, which Waco and communities south are working to take in.
It's bad. Also important to note, given the horror of this week, the explosion happened after the fire broke out, not the other way around.
UPDATE: All residents are being advised to evacuate. West's population is about 3,000
UPDATE2: They moved the triage center from the football stadium due to toxic fumes. Reports of 20 firefighters lost. State Troopers are loading injured people into their cars to take them to hospitals, there aren't enough ambulances.