an article at The Guardian,
Hungary declared a state of emergency in three counties yesterday after a dam burst at an alumina plant in Ajka, releasing a torrent of toxic red sludge that swept through local villages. Four people were killed, three reported missing and 120 were injured.And below is some video of the deluge, posted by The NYT, (more video of the cleanup at the link) looking for all the world like something out of a Bible story.
I haven't seen anything on the composition of this material, but apparently, it's quite alkaline- many of those hospitalized are suffering from chemical burns. I'd presume a large component is iron oxides- iron oxides and aluminum oxides make silica (SiO2) look highly soluble, but reports are saying there are lots of other toxic metals in this witch's brew. Gack.