Classes resumed at the Manual Educational Complex Monday morning after two private haz-mat consultants and the Denver Fire Department's Haz-Mat Unit declared the school environment safe.

Principals of each school in the complex plan to meet with students to brief them on the weekend's activities. A crisis team will be available to students who want to talk about the incident.

Air samples taken shortly after the school was closed down Friday afternoon showed barely detectable levels of Aldahyde, which could be an indicator that a mace-like substance was sprayed in the air. These levels were way below regulatory limits.

Over the weekend, the school was thoroughly cleaned and ventilated. After the air was tested and re-tested for organic, radiological, and chemical substances, both haz-mat consultants and the Denver Fire Department agreed it was safe for students to return to school Monday morning.

Friday afternoon, ten students and seven staff members were taken to area hospitals complaining of coughing, headaches, and nausea. They were treated and released by the end of the day. A telephone tree was set up to provide updates on the matter to parents throughout the weekend.