Yah, saw that in coverage. The owner of the plant has a lot of explaining to do - as well as the TX Dept. of State Health Services, which apparently spectacularly failed to notify DHS of the stockpile.
Nor were local first responders notified, which would have prompted them to pull back & possibly saved lives. Also, a blast wall should have been built around the plant, & special zoning should have been put in place, to keep apartments & old-age homes, schools, nurseries, daycare centers, etc. from being built within a reasonable distance. (The blast exceeded any reasonable distance, of course. No one in public safety apparently knew anything about the powderkeg they were sitting on.)
Which is probably why the owner didn't report - after all, who was he hurting? We have an answer now, & he & his corporation will likely go bankrupt from fines, penalties, denial of permitting, civil suits. Even so, I don't think he's going to sleep well for a v. long time ...