This comes as a chemical plant that is swamped by about six feet of water in Crosby, about 25 miles northeast of Houston, saw two explosions early Thursday morning, sending thick black smoke into the air. The Harris County Sheriff’s Office on Thursday downplayed the threat posed by the plant’s chemicals. But Federal Emergency Management Agency head Brock Long said a plume of chemicals leaking from the plant was “incredibly dangerous.”

Brock Long: “So, the bottom line is, is that we do what’s called plume modeling, and that’s what we base a lot of the evacuations on. And so, by all means, yes, the plume is incredibly dangerous.”