CROSBY, Texas – The fire burning at Arkema's Crosby plant was extinguished early Saturday morning, according to plant officials.

An Arkema spokesperson said Saturday there are still concerns additional containers could reignite.

There were plumes of black smoke and flames shooting into the air on Friday in the 18000 block of Crosby Eastgate Road.

Explosions from chemicals, and it was all as expected according to the company responsible for the chemicals.

"One container became engaged then the heat from that container is what actually initiated and ultimately fire from the second container," Richard Rennard, with Arkema, said. "This played out like we'd expected it to."

Two trailers burned, housing what Arkema Inc. said are organic peroxides.

One trailer burned Thursday.

After Friday's fires, six more trailers remain that are likely to catch fire.

VIDEO: Sky 2 surveys Crosby Arkema plant fire

"The product is going to warm up. It's going to begin to downgrade and then it's going to catch fire, just like it did today (Friday)," Rennard said. "The storm came in very quickly, water rose very quickly. We didn't feel like we were going to be in a situation where all of our redundant levels of protection were going to be compromised."

They catch fire because they can't handle being stored in hot conditions.

Arkema said the chemicals were stored in a warehouse facility, which was temperature appropriate.

Once Harvey knocked out power, backup generators were brought in.

VIDEO: Officials provide update on Arkema situation

Then the facility flooded, killing the generators.

The chemicals were then stored in trailer trucks, which don't have refrigeration.

An employee from a company called Dexter Field Services, out of Beaumont, was at the perimeter set up around the plant Friday.

The company tests air quality, among other things, according to its website.

Officials also said the Environmental Protection Agency is testing the air and water.

Arkema said the burning that's occurring is not toxic.

They also said this was a worst case scenario they didn't see coming.

Arkema issued the following statement Thursday:

"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. Local officials had previously established an evacuation zone in an area 1.5 miles from our plant, based on their assessment of the situation.

"We continue to work closely with federal, state and local authorities to manage the situation.

"As we communicated in recent days, our site followed its hurricane preparation plan in advance of the recent hurricane and we had redundant contingency plans in place. However, 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.

"We have been working closely with public officials to manage the implications of this situation, and have communicated with the public the potential for product to explode and cause an intense fire. Organic peroxides are extremely flammable and, as agreed with public officials, the best course of action is to let the fire burn itself out.

"We want local residents to be aware that product is stored in multiple locations on the site, and a threat of additional explosion remains. Please do not return to the area within the evacuation zone until local emergency response authorities announce it is safe to do so.

"Organic peroxides are a family of compounds that are used in a wide range of applications, such as making pharmaceuticals and construction materials."

Rennard said that when the plant was shut down Friday ahead of the storm, the company left behind a team of 11 people to ride out the storm and ensure the safety of the chemicals. He said that team was later evacuated after the failure of the refrigeration units.

While the fire is burning, residents near the facility might be exposed to smoke and other combustion irritants.

Harris County officials said residents should stay indoors, close all windows and shut off air conditioning.

For more information call Arkema's hotline at 877-4-ARKEMA or visit arkema.com.

Download the Click2Houston news app in your app store to stay up-to-date with the latest news while you're on the go.

Sign up for KPRC 2 newsletters to get breaking news, sports, entertainment, contests and more delivered straight to your email inbox.