By Trang Do

PHILADELPHIA (CBS) — In the plight of Philadelphia schools with asbestos, officials have agreed to joint asbestos testing with the teachers union at Carnell elementary, according to a spokesperson for the Philadelphia Federation of Teachers. Students returned to class at Laura Carnell Elementary School Monday for the first time in three weeks after the building was shut down for asbestos clean up, but some are questioning if the building is safe for students and staff to return.

A group of Carnell educators met with Philadelphia Federation of Teachers’ President Jerry Jordan before the bell, amid concerns about the building’s safety.

“I can’t say whether it’s safe because we have not been able to do a testing of the various areas to determine that and that’s the problem,” President Jerry Jordan said.

An inspection of the school building before winter break identified 150 areas with damage that left asbestos exposed, 12 of those were deemed imminent hazards. The school was then shut down for repair and asbestos removal.

“We completed extensive work over the past couple of weeks, and we’ve also tested,” said Megan Lello, a School District of Philadelphia spokeswoman. ”We tested 350 different samples that go above and beyond industry best practices and regulations, all of the tests came back clear.”

But the PFT says the school district did not go far enough and did not include the union’s environmental scientist in the testing process.

“Very different situation than at McClure [Elemenatry] as an example,” said Jerry Roseman, environmental scientist for the teachers’ union. “Most of the asbestos was removed at that school. Most of it was left at this school.”

In a letter to parents, the school district wrote that there are still five closet areas not accessible to students or staff that still need to be remediated. Parents we spoke to had mixed reactions to the response, with some supportive of the union and others siding with the school district.

“They really took their time, it took about three weeks or so, so I feel like they took their time to get down to the bottom of it,” said one parent named Yanna, who declined to give her last name. “It definitely didn’t come across as if they rushed it.”

“They need to get things in place so that they can have a safe place to go for all the kids as well as all the teachers,” said Rishawn Reynolds, who has a fourth grader at Carnell. “The teachers are already underappreciated and underpaid, now you want them to put their lives on the line?”

Meanwhile, students at McClure Elementary School in Hunting Park have also been out of school for three weeks. McClure is set to reopen on Wednesday.