PHILADELPHIA (CBS) — A sight and sound not seen in more than a year-and-a-half: excited students heading back into a school building without the boundaries of virtual learning.

“I’m looking forward to seeing my friends,” student Iman Clark said. “I’ve only been able to see them through a little glass screen.”

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Hundreds of students filed into the Science Leadership Academy Tuesday morning for the first day of school for the Philadelphia School District.

Parents looked on as they were finally able to see their children off to in-person learning for the first time since the pandemic.

“Oh my goodness, I’m so elated,” a parent said. “They get to see their friends again.”

No one seems more excited than Superintendent Dr. William Hite and Mayor Jim Kenney as they greeted students entering the building.

It’s been a monumental task to get as many as 223 school buildings safely ready to open in the midst of an ongoing pandemic. But there are also the continued environmental safety concerns surrounding asbestos from staff returning to older buildings.

“There’s always nerves around the first day. In fact, my nerves started on Sunday night and carried right on through this morning,” Hite said. “It is absolutely nerves and anxiety.”

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CBS3 caught up with students and parents at the end of this long-awaited day.

“It’s really overwhelming,” a parent said. “I was unexpectedly really overwhelmed when we dropped them off this morning. Because all the parents are here. All the parents are here. There was a buzz.”

“It was the best,” a student said. “Well, I get to meet new friends and I see my new teachers.”

Hite touted a good first day but he’s also keeping a close eye on a looming strike by the teacher’s union. The contract ends at midnight and he’s hoping a strike can be averted.

“I don’t think it’s going to get to that,” Hite said. “Just given the activity that’s happening with respect to the negotiations team.”

There is a teacher’s union meeting Tuesday night to discuss the matter.

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“Let me be clear. We’re on the brink of a strike vote this evening,” Philadelphia Federation of Teachers President Jerry Jones said. “It can and should be very easy for the district to avoid this. But they have to get serious.”