School leaders say once they felt that blast, they took precautions quickly.
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"We heard a loud boom and the wall shook with the window, and we immediately went into lockdown procedures," recalled kindergarten teacher Tara Havard.
She along with other teachers inside the school duct-taped the doors to keep any potential chemicals in the air out.
"We were told through chain of command to do that," she explained.
The district was under a "shelter-in-place" for several hours.
"We've had some emergency situations, but not like this, not with a plant nearby," said Patricia Kay, Crosby ISD's assistant superintendent of student services.
Administrators made sure their students and staff were safe.
"Parents grew very anxious, understandably so. They wanted to get their kids. We had the doors sealed," Kay explained.
Joshua Seale has three daughters in the district. He appreciated school leader's quick thinking.
"I was pretty confident that my girls were safe and in their classrooms where they're supposed to be," he said.
Some teachers at Crosby Middle School used the incident as a learning experience in the classroom. Ironically, eighth grade science students are learning about long and short-term environmental changes.
"We had a conversation with the kids about what would you consider this to be a long-term or short-term environmental change," said teacher Joyce Baecker.
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