The school was put on lockdown as a bomb squad was sent in to determine if the backpack posed any threat. Homes in the nearby area were evacuated.
Los Angeles Fire Department officials also responded to the scene to check students for possible heat-related issues.
The lockdown was lifted around 11:35 a.m. after authorities determined the suspicious backpacks were students' personal belongings, and classes resumed as scheduled.
No one was treated for any heat-related ailment. While parents criticized some chaos, many said they are glad the school had a plan.