Sequoyah Middle School staff say they have been experiencing nausea, dizziness and respiratory problems since returning to campus Aug. 3.

The teachers suspect the symptoms are connected to asbestos abatement work the DeKalb County School District completed in the school's main building before staff returned. The district says a third-party environmental company cleared the building for occupancy before the school year started. WSB-TV Channel 2 first reported the complaints on Wednesday, Sept. 2.

Sequoyah, a DeKalb County School District campus, enrolls about 1,713 students in grades 6 through 8. The school sits next to an active construction site where a new middle school and high school campus is being built to replace the current buildings.

One teacher told WSB-TV reporter Tyisha Fernandes she feels nauseous and dizzy every time she enters the main building. Another with pre-existing respiratory issues said she had to relocate to a separate building after her symptoms worsened.

Staff also photographed a black substance inside the building that they say appeared after the abatement work. No authority has publicly identified the material.

WSB-TV reported that a teacher filed a formal complaint with the Georgia Environmental Protection Division (EPD). In that complaint, the teacher wrote she had experienced "brain fog, dizziness, nasal congestion, coughing and unsteadiness" since returning to work.

The Georgia Department of Natural Resources (DNR) followed up by contacting the abatement contractor. According to a DNR email obtained by WSB-TV, the contractor expressed confusion about the material and asked for a site inspection. The email also stated the contractor's company apparently did not apply the sealant in question.

Principal Lauren Pells sent a letter to Sequoyah families on Sept. 2 acknowledging the situation. Pells said the building passed required clearance testing before students arrived. She also disclosed the school is short six custodians and said additional cleaning staff were being brought in that night. The letter noted the school is addressing areas with leaks.

The names of the abatement contractor and the environmental firm that issued the clearance letter have not been made public. Whether families were notified about the asbestos work before the school year began is also unclear. The district told WSB-TV it was preparing a more detailed response.