An independent environmental contractor has determined that mold is not a health threat at the troubled District Heights Elementary School, but the ventilation system is in terrible disrepair, according to the Prince George’s County Board of Education member who represents the school.

The "stagnant air" resulting from going months with poor ventilation might explain health complaints from teachers, according to K. Alexander Wallace.

Twenty three of 25 rooftop exhausts fans were found to be inoperable, Wallace said.

Wallace is calling on a roofing contractor that worked on the building over the summer to be held accountable for leaving the job with exhaust fans inoperable. He says employees who suffered health effects that can be linked to poor ventilation should have sick leave time restored.

RELATED: Prince George's Co. bus drivers worried office infested with mold

Repairs have been underway since late March, according to Prince George's County Public Schools spokesperson Raven Hill.

Four employee unions have called for the school to be closed and for classes to be moved to other school buildings. Teachers, in particular, are concerned about persistent reports of mold in the building linked to a leaky roof.

Angry parents questioned the safety of children at a community meeting Monday. On Friday, many were left confused.  

“I don’t know what to do. I hate to take him out of school,” said grandmother Ellen Keys.

According to results from tests done by environmental health contractor Tidewater Inc., nine out of 10 air samples taken in the school March 30 and 31, showed levels of mold inside the building were lower than mold drifting naturally in outdoor air. A tenth sample showed a mold level slightly higher than the background level outdoors.    Additional testing is being done.

"The total indoor mold spore counts at District Heights ranged from 130 to 1,250 spores per cubic meter; the outdoor mold spore count was 990," according to a written statement from PGCPS. "All but one classroom area were well below the outdoor count. The classroom with the marginally elevated – but not toxic – mold spore count was relocated as a precaution."

Click here to read full statement. 

In addition to the repairs on the 23 rooftop exhaust fans, 11 of 26 classroom ventilation systems are being cleaned and repaired.  Additional work will include the replacement of stained ceiling tiles and air filter replacements, according to the school system's statement.

An additional $1 million in heating and cooling system and roofing repairs are scheduled through the summer, according to Hill.

Wallace says he is convinced the school is safe from mold contamination.

"The ten spots that we tested with that third party contractor that the principal identified that were areas of her concern were proven to be safe," he said.

District Heights Elementary school is 40 years old. The average age of school buildings in Prince George's County is 60. 

Wallace said the issues revealed by the mold scare at District Heights are a symptom of decades of "piecemeal" maintenance caused by budget shortfalls.

"It’s like putting Band-Aids on broken bones," Wallace said.