Parents in Northport staged another "sick out" protest Monday morning at the middle school.

As News 12 has reported, they're calling for the building to be shut down.

The move comes after an environmental firm found elevated levels of mercury and other heavy metals outside the building.

Former staff and students say the school has been making people sick for years.

"Other teachers are sick, current teachers, retired teachers, staff members, secretaries… 20 have passed away from that cancer," said former teacher John Cobel.

"The board is not doing their job, they are not doing the right thing right now, they are covering up, they lied to us repeatedly," said former student Michael Marcantonio.

The school closed several classrooms as a precaution.

Tests show mercury levels not detected in the air at Northport Middle School 

Environmental firm to investigate odors at Northport Middle School 

Northport parents rally after new odors enter middle school 

'Sick out' planned in protest of foul stench at Northport Middle School