WESLACO – School district officials released Weslaco High School students early as a precaution after at least 29 students and one teacher were affected by a gas-like odor.

Within the hour, parents were notified and seen lining up the entrance of the campus.

Weslaco Police Chief Joel Rivera says the gas came from a science classroom.

The school district notified parents and asked them to pick up students at the Sepulveda Gym. Other arrangements were made with school transportation.

Authorities directed heavy traffic as hazmat crews identified the source. 

Watch the video above for the full story.