Authorities have confirmed there were fatalities in the explosion at the fertilizer plant in the town of West – just north of Waco – though they have not said how many.
Today, Gov. Rick Perry has declared a disaster in the area.
As for the explosion itself, much of the focus has been on the chemicals stored at the West Fertilizer Company, where the massive explosion happened.
Two chemicals – ammonium nitrate and anhydrous ammonia – were stored there. For more on those chemicals, we spoke with UT Austin chemistry professor David Vandenbout.
Alone, anhydrous ammonia and ammonium nitrate are not known as flammable substances. But both - and ammonium nitrate in particular - may be very dangerous when mixed with other chemicals, such as diesel fuel or oil.
When mixed, ammonium nitrate may be used to create explosives, as it was in the 1995 Oklahoma City bombing.
Anhydrous ammonia may also create an explosion when mixed with other chemicals and ignited. But it requires a particular amount of oxygen. The greater danger with anhydrous ammonia is exposure through breathing in the chemical or having in come in contact with your skin.