This story, which has been updated early Thursday with news of explosions at the site, was originally published by the Texas Tribune.

Two explosions rang out overnight in Crosby, Texas, at the site of a chemical plant owned by Arkema Inc. that’s under six feet of floodwater.

Organic peroxides used in the site’s manufacturing process had begun to heat up after the plant lost its primary source of power, then lost the power from its back-up generators that ran refrigerators to keep the chemicals stable.

At around 2 a.m. local time, Harris County Emergency Operations Center officials reported the two blasts and said black smoke was seen overhead. Company and government officials warned of additional explosions as the chemicals at the site break down. A company official, in a statement early Thursday, said “the best course of action is to let the fire burn itself out” because of complications of handling the volatile chemicals in even the best of circumstances.

At least one emergency responder was hospitalized after reporting dizziness from exposure to the chemical clouds after the blasts, according to the county sheriff’s Twitter feed.

“The materials could now explode and cause a subsequent, intense fire,” Rich Rowe, Arkema’s president and CEO, warned Wednesday at a press conference. “The high water and lack of power leave us with no way to prevent it.”

The facility evacuated all of its employees Tuesday, and approximately 300 people living within 1.5 miles of the plant have been voluntarily evacuated as well. Rowe described this evacuation radius as “conservative,” and said he expects that the effects of a fire or explosion would be contained on the site’s facilities.

Unless the floodwaters recede, Rowe said, it is not possible to enter the facility. Local officials have told the company that the water level may not recede for as long as six days—and Rowe anticipates that the chemicals on site would “certainly” begin to degrade before six days have elapsed.

Still, Rowe said the fire is “nothing that would pose any long-term harm or impact,” and any sustained environmental impact would be “minimal.”

The plant, which is located northeast of Houston, was shut down on Friday in anticipation of the hurricane. None of the plant’s chemical inventory was relocated prior to the storm.