Construction at an elementary school in Highland Park, Virginia, revealed the presence of lead paint on ceiling tiles being removed at the 100-year-old school.

The construction, which started last winter, reportedly released lead paint chips throughout the school as workers overhauled its dated HVAC system, according to the Roanoke Times.

Six teachers have since reported various symptoms that they associate with exposure to lead, including one teacher who has filed suit against the school system and has refused returning to the the Highland Park school, the news source reports.

An investigation by the Virginia Department of Labor and Industry (DOLI) began back in February following reports from the teachers and workers on the site. The investigation led to the DOLI citing the school for unsafe working conditions that pose the potential risk of lead exposure.

A second citation was issued to the school for failing to use vacuum filters designed specifically for use in the removal of lead paint chips on surfaces.

The school system is currently appealing the citations, claiming that the school building is structurally and environmentally sound. Other than the six teachers who reported illness from exposure to lead paint, the school has no records of students showing signs of lead poisoning or exposure, school officials told the source.

A spokeswoman from the DOLI told the source that because the school is a government-run entity, they have no authority to impose fines on the school, though the citations given referred to the issue as quite serious.

Lead paint was officially banned by the U.S. Consumer Product Safety Commission in 1977 following the exposure of links between developmental issues in children and the ingestion of lead-based paints.

Individuals who live or work in buildings constructed before the ban on lead paint took effect should seek a home or commercial inspection to investigate the potential presence of lead in these structures.