HOUSTON (CBSDFW.COM/AP) – Popping noises were reported early Thursday at a Houston-area chemical plant that had lost power on Sunday amid flooding from Harvey. A statement from Arkema Inc. said that the Harris County Emergency Operations Center reported two explosions and black smoke coming from the plant after midnight.

Officials later retracted that statement. “Wasn’t an explosion, I want to be very clear,” said Harris County Sheriff Ed Gonzalez later Thursday morning. He explained that it was a chemical reaction that was “expected and planned.” That is what led to the popping sounds and smoke.

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Speaking Thursday at an early morning briefing in Washington, FEMA Administrator Brock Long called the plume of smoke “incredibly dangerous.”

The Environmental Protection Agency and local emergency officials, however, later said airborne sampling showed the smoke did not contain concerning levels of hazardous materials.
Asked about the discrepancy, a FEMA spokesman said Brock would defer to the officials closest to the incident to make warnings and safety determinations.

Gonzalez said that the plant stores different organic peroxides that must be kept at a certain temperature. After the plant lost power, this temperature could no longer be maintained. The reaction happened when the chemicals left the temperature that they require, creating the popping noises that were originally mistaken for explosions.

In a tweet, the Harris County Sheriff’s Office stated that one deputy was taken to the hospital after inhaling fumes. Nine other deputies drove themselves to the hospital as a precaution. They are all expected to be okay. Officials added that the smoke was not toxic.

Another tweet from the Harris County Fire Marshal’s Office confirmed that there had been “a series of chemical reactions” at the plant and advised people to stay away from the area. Emergency workers were at the scene and took a defensive posture to make sure that the chemical reaction did not become dangerous.

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A spokeswoman for the Crosby plant said late Wednesday that the flooded facility had lost power and backup generators amid Harvey flooding, leaving it without refrigeration for chemicals that would become volatile as the temperature rises. The plant is located about 25 miles northeast of Houston.

“The fire will happen. It will resemble a gasoline fire. It will be explosive and intense in nature,” spokeswoman Janet Smith warned The Associated Press on Wednesday. Arkema manufactures organic peroxides, compounds which are used for making everything from pharmaceuticals to construction materials.

There was “no way to prevent” the explosion, chief executive Rich Rowe also said Wednesday.

The company shut down the Crosby site before Harvey made landfall last week, but a crew of 11 workers stayed behind. That group was removed and residents within 1.5 miles were told to evacuate Tuesday after the plant lost its backup generators.

The plant falls along a stretch near Houston that features one of the largest concentrations of refineries, pipelines and chemical plants in the country.

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(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)