Students and staff briefly sheltered in place Tuesday afternoon at Duncanville High School after a student set off fireworks on campus, school and police officials said.
Duncanville Independent School District spokeswoman Lari Barager said there was not an active shooter incident as police call records showed.
The school district responded to questions on Twitter saying "there is no immediate safety concern at Duncanville High School."
The fire alarm was "activated" and students evacuated the school building.