HARRIS COUNTY, Texas — One person has died and two others were badly injured in an explosion and fire Tuesday at a Crosby chemical plant in east Harris County.

The explosion at the KMCO plant happened around 10:45 a.m.when a transfer line ignited a tank full of a chemical called isobutylene. The Harris County Fire Marshal's Office said the fire was contained by 4:20 p.m.

"It was terrifying. It was definitely terrifying... I don't know...there's always a danger but you never expect it to happen." an employee named Justin told KHOU 11.

He said employees made a mad dash for the exits.

RELATED: 'A mad dash to the exits': Employee describes Crosby plant explosion

Residents around the area reported a similar experience.

“The whole house shook,” said Dana Bushnell. “My windows vibrated, my dog was barking, the alarm was going off.”

“All at once I heard a big noise and my house shook!” said Roosevelt Stanley. 

READ: Crosby plant explosion could be heard, felt from miles away

Employees inside the KMCO plant describe the moment as terrifying. 

“Next thing you know there’s a huge explosion and you just saw people running out of the gate,” said KMCO employee Ben Villarreal.

Authorities say the fire started in a transfer line then quickly spread to a nearby tank and warehouse burning at least three chemicals: isobutylene, Ethanol and Ethyl acrylate.

Tuesday evening, Attorney General Ken Paxton filed a petition against KMCO for violations of the Texas Clean Air Act. HCFMO issued a subpoena to the plant as part of their investigation. 

The subpoena will preserve documents related to KMCO and aid investigators in figuring out the cause of the fire. 

“I offer my condolences to the families who have suffered injury or loss and to the community impacted by the KMCO fire earlier today,” says TCEQ Executive Director Toby Baker. “I applaud the attorney general for acting swiftly on my requests to hold KMCO fully responsible.”

RELATED: Chemical called isobutylene caused explosion, fire at Crosby chemical plant

RELATED: KMCO was criminally convicted of violating Clean Air Act in 2016

KHOU 11 viewers in Houston, Kingwood and Deer Park said they felt the explosion.

A large cloud of black smoke could be seen for miles throughout the day.

Harris County Sheriff Ed Gonzalez he heard a few "pops" coming from the plant after arriving on the scene.

Dozens of firefighters from Houston, Crosby and other communities battled the blaze for six hours. 

The shelter-in-place advisories for nearby residents and all schools were lifted around 2:15 p.m. As a precaution, HISD canceled outdoor activities at eastside campuses, along with a few other northside schools. See complete list here.

Late into Tuesday night, fire crews could be seen spraying water onto the KMCO plant in Crosby, trying to ensure that what was a deadly fire earlier in the day stayed extinguished.

“It was shocking because it just happened,” said Bushnell, a mother of four picking up her kids from school. “I’m like, what is going on with these chemical plants?!”

“It is disturbing,” admitted Harris County Judge Lina Hidalgo during a press conference, “and it is problematic that we are seeing this incident at a facility especially on the heels of ITC.”

KMCO’s president, John Foley, offered an apology to the community.

“An apology for creating the situation...the worry, the angst. We take our commitment to the community and employees very seriously. It’s a great tragedy what happened here today," he said.

Sheriff Gonzalez said the Harris County Fire Marshal's Office will take the lead on the fire investigation. 

The EPA is also monitoring air quality.

TCEQ has also sent emergency response personnel, along with an air quality van, to the vicinity.  

KMCO was criminally convicted of violating the Clean Air Act in 2016, KHOU 11 Investigates found, and was ordered to pay part of $3.3 million in criminal fines. The company has also been fined 10 times by the Texas Commission of Environmental Quality (TCEQ) since 1995.

The company sent out the following statement: 

"There was an incident resulting in an ignition and fire today April 4, 2019 at KMCO, LLC in Crosby Texas. We are deeply saddened to confirm at this time that there have been injuries and one fatality. Those injured have been transported for medical treatment. Our hearts and prayers go out to the individuals involved, as well as our first responders, employees, and our community.

We have activated the company’s emergency response team and incident command center. We are working with local first responders to extinguish the fire. We will give another update as additional information becomes available."

We apologize for any inconvenience to residents in the vicinity. The wellbeing of our people, neighbors and the environment remain our top priorities.

This was the second major chemical plant fire in the Houston area in the last two weeks. The ITC fire that started on March 17 in Deer Park burned off and on for a week.

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