Elementary school children have been hospitalized in Michigan.
42 pupils were evacuated Wednesday morning from Macomb Township school.
Five children fell unconscious before the rescue crews came in.
Initial reports from doctors say that the kids were showing signs of upper respiratory irritation.
A fog machine that was being used by the school is believed to have caused pupils to be sick.
Rescue workers were at the scene helping students aged 9 to 12 to get into ambulances and leave the school.
Fire Chief Robert Phillips mentioned the fact that fog machine smoke was being run with dry ice, "is an abnormal method to operate a fog machine."
The authorities are trying to find out what made so many pupils to fall sick. MedStar ambulance director of operations Scott Hicks noted that more of them can be hospitalized in the near future because of the complications.