Hazmat teams were called to the Holy Redeemer School in Kensington Friday morning after several students complained of throat irritation and breathing problems.
Crews arrived to the school at 9715 Summit Avenue in Wheaton at about 9:45 a.m. and found at least seven students overcome, officials said.
Montgomery County fire officials evacuated the school and are evaluating the students.
None of the illnesses appear to be life-threatening, officials said.
The school will remain locked down as the investigation continues.
It is unclear what may have caused the students' illnesses.
