The children were from the third-grade at an elementary school in South Amboy.
Two classrooms were complaining of nose, eyes and throats burning.
The Middlesex County HazMat team and the fire department responded and got a negative reading for any hazardous conditions.
The school was evacuated, but the students later returned for an early dismissal.
"When they went in they said they had a slight odor, we went in there with meters, our meters said zero," said South Amboy Fire Chief John Kelly. "We called county HazMat and they came out with their meters, they also came out with zero readings."
"They just said that there was a weird smell and there was a teacher and a few students that had to be brought to the hospital and immediately, I didn't know if it was one of my kids that had to be taken to the hospital," said parent Patrick Asseng.
The Superintendent of the South Amboy Schools ordered the two classrooms where the children complained of feeling ill to be closed and secured for the rest of the day.
Local officials will continue to monitor the classrooms during the day and Thursday morning as they investigate the source of the odor.
Source : https://abc7ny.com/news/dozens-of-students-sickened-by-unknown-odor-in-new-jersey-school/1227951/