Local emergency officials on Thursday reported two explosions at a flooded chemical plant in the Texas town of Crosby, its operators Arkema Inc said.

"At approximately 2 am CDT (0700 GMT), we were notified by the Harris County Emergency Operations Center (EOC) of two explosions and black smoke coming from the Arkema Inc plant in Crosby, Texas," the company statement said.

As a precautionary measure officials had already ordered the evacuation of an area within 1.5 miles (three kilometers) of the organic peroxides plant, which operators had said was at risk of exploding due to a "critical issue" triggered by monster storm Harvey's torrential rains