In Crosby, the chemical plant's operators, citing local officials, initially said two blasts rocked the facility after it was rendered powerless by floodwaters.
"We were notified by the Harris County Emergency Operations Center of two explosions and black smoke coming from the plant," the company, Arkema, said in its initial statement.
Other accounts soon followed. The Harris County Fire Marshal's Office reported "a series of chemical reactions" and "intermittent smoke" at the facility; a county official said there weren't "massive explosions," and instead referred to the reactions as "pops" followed by fire. William 'Brock' Long, administrator of the Federal Emergency Management Agency, had called the potential for a chemical plume "incredibly dangerous" at a briefing Thursday morning.