Emergency vehicles Arkema plant Texas
© Brendan Smialowski / AFPEmergency vehicles wait at a roadblock after a chemical plant operated by the Arkema Group had an explosion during the aftermath of Hurricane Harvey on August 31, 2017 in Crosby, Texas.
Arkema chemical plant in Crosby, Texas has confirmed that two explosions have occurred at the site. People have been taken to the hospital, according to emergency workers, cited by local media.

"At approximately 2 a.m. CDT, 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," Arkema wrote in a statement.

The statement goes on to say that although the plant followed hurricane preparation protocol, "unprecedented flooding overwhelmed our primary power and two sources of emergency backup power. As a result, we lost critical refrigeration of the products on site. Some of our organic peroxides products burn if not stored at low temperature."

"Organic peroxides are extremely flammable and, as agreed with public officials, the best course of action is to let the fire burn itself out," the statement reads.

Arkema says it is working "closely with federal, state and local authorities to manage the situation."

However, Harris County Sheriff Ed Gonzalez stressed during a press conference that "it wasn't an explosion, I want to be very clear, it was not an explosion..."

He instead explained the incident as a series of "pops."

"There were different organic peroxides of different grades that were released and it created a pop in the containers where they were being stored and some gray smoke initially emanated from it and eventually turned into black smoke" after a fire began.

Gonzalez went on to state that it is "not anything toxic, it is not anything that we feel is a danger to the community at all..."

The "pops" occurred inside one of nine box trucks at the site, according to Bob Royall, an assistant chief with the Harris County Fire Marshal's Office.

"There are nine vans. Of the nine, three had lost refrigeration to keep them cool. the other ones are still under refrigeration," he said, adding that the chemicals are "in containers in cardboard boxes inside the vans."

The operator of the plant has confirmed that up to eight more containers could burn and explode, according to AP.

Meanwhile, Royall has said the incident is playing out as expected.

"Right now everything is going according to what we thought was going to happen so far. We are in a defensive posture, the fire department is out there on the scene, there is air monitoring being deployed by a contractor by the company to try to find out and watch and see where the smoke might go..." he said.

A sheriff's deputy was among those taken to the hospital after inhaling fumes, according to a tweet from the Harris County Sheriff's Office. Nine other deputies drove themselves to the hospital as a precaution.

"We had a number of deputies out there that were maintaining the perimeter. As a precaution, they were taken to a nearby hospital for testing..." Gonzalez said.

Rachel Moreno, a spokeswoman for the county fire marshal's office, said it is unclear whether all residents obeyed the evacuation order for the 1.5 mile radius of the plant, adding that the office has received an unconfirmed report of a woman who may still be in the evacuation zone.

An Arkema spokesperson stated late Wednesday that a fire at the site was inevitable.

"The fire will happen. It will resemble a gasoline fire. It will be explosive and intense in nature... as the temperature rises, the natural state of these materials will decompose. A white smoke will result, and that will catch fire. So the fire is imminent. The question is when," spokesperson Janet Smith said.

The plant makes organic peroxides used in the production of plastic resins, polystyrene, paints, and other products.

Organic peroxides are "relatively unstable compounds which can decompose spontaneously and sometimes explosively,"according to Arkema's Luperox website. They are "generally flammable and burn vigorously."

When such compounds reach a temperature above the SADT (Self Accelerating Decomposition Temperature) the reaction becomes "uncontrolled and violent."