CROSBY, Texas — Fifteen Harris County deputies were exposed to a "non-toxic irritant" Thursday after a refrigeration truck container holding chemicals caught fire at an Arkema plant.

Arkema executive Richard Rennard said the company "fully expects" eight more containers to burn at the flooded plant. He said anyone exposed to smoke or fumes from the plant should seek medical attention because the smoke could cause irritation to eyes and lungs.

“What we have going is not a chemical release," he said. "This is a fire. And when you have a fire where hydrocarbons are burning — sometimes you have incomplete combustion and you have smoke."

Sheriff Ed Gonzalez said one deputy was taken to the hospital by ambulance and 14 others drove themselves as a precaution. All were released a short time later, he said.

“It is not anything toxic,” Gonzalez said. “It is not anything we feel is a danger to the community."

A mandatory evacuation zone with a 1.5-mile radius was established as a precaution. The incident was first reported by emergency officials as two explosions, but law enforcement later said relief valves on the containers popped, spewing black smoke and fire. 

Assistant Fire Chief Bob Royall said these were expected reactions that would lead to fires burning until the organic peroxide in the containers burned out.

Initially, the Harris County Emergency Operations Center notified the company of two explosions at the site and also reported black smoke coming from the area around 2 a.m. Royall said company officials have been consulting with chemists and believe they've developed a safe plan to handle the situation and feel like it will be contained to the facility. 

Air monitoring is being deployed to figure out where the smoke might go, and Royall said the 1.5-mile evacuation zone was sufficient.  

Arkema had previously said that sometime within the next several days chemicals at the plant would likely degrade and catch fire because the refrigeration storage and backup procedures had failed. 

Rennard said the plant started taking measures to shut down the plant before Hurricane Harvey roared onto the Texas coast Friday. He said "multiple layers of protection" were designed to provide refrigeration for the materials that need it.

When the storm hit, the plant lost power and emergency generators were used. Those, too, were compromised by the flood.

“We actually have a third system in place which was liquid nitrogen," he said. "But because of the floodwaters some of the equipment necessary to operate liquid nitrogen system was compromised."

The fourth layer of protection was the refrigerated storage containers in which the chemicals are now stored. And they are warming up.

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On Wednesday, Richard Rowe, the chief executive of the company's North America unit, said that while the plant made "extensive preparations," a fire would be likely.  

Rennard said trucking the containers away from the plant wasn't an option.

“We certainly did not want to bring these containers on the roads with hundreds of thousands of people being evacuated and having a trailer stuck on highway somewhere," he said. "We felt the safest place to keep containers and to protect the citizens in the area was to keep the product on our site.”

It appears that outcome is underway and more explosions could occur because the organic peroxide is stored in multiple locations. 

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

According to Arkema, the fires resemble a large gasoline fire. It would be "explosive and intense" and smoke would be released into the atmosphere and dissipate.

The preparations included having backup generators on site and diesel-powered refrigerated containers to hold the organic peroxide. But all those measures have failed due to floodwaters overcoming the entire facility, which is only accessible now by boat. 

“We are not going to put anyone in harms way to try to restore refrigeration because we don’t know the state of the product in the container," Rennard said.

In a statement, the company wrote that there's also a small chance the chemical could release into the floodwaters and not burn. 

Officials said chemical refrigeration at the plant had been compromised because of high water and lack of power.

Employees at the plant were evacuated and families were being evacuated into Wednesday. There are 57 employees who work at the facility.   

"At Crosby, we prepared for what we recognized could be a worst case scenario," Rowe says. "We had redundant contingency plans in place."

The plant makes organic peroxides, which are used in a variety of things from pharmaceuticals to construction materials. The company says the fires from the burning organic peroxides will emit a thick black smoke that could irritate the eyes, skin and lungs

The Arkema site in Crosby had been shut down since Friday in anticipation of the storm.

According to the Environmental Protection Agency, there are about 1,300 households and 3,800 people in a three-mile radius of Arkema. The plant’s chemical inventory includes acetone, benzoyl chloride, chlorodifluromethane, cumene, cumene hydroperpoxide, DI(2-ethylhexyl) phthalate, ethybenzene, ethylene glycol, hydrochloric acid, mercury, methyl ethylketone, n-hexane, sodium hydroxide, sodium sulfate, sulfuric acid and butyl alcohol.