A student who was poisoned by a toxic chemical in a Kansas University lab did not follow proper lab procedures, university officials announced Wednesday.

The graduate student, who the university has refused to identify, accidentally ingested the highly toxic chemical sodium azide and was later admitted into the intensive care unit at Lawrence Memorial Hospital. The incident happened Nov. 4 inside Malott Hall and caused the student to be hospitalized for three days.

“Everyone is relieved that the student has recovered,” university spokesman Jack Martin said in a news release.

University officials said the student apologized to his lab colleagues for “his lapse.”

The situation caused officials to evacuate and close Malott Hall for a short time while safety workers confirmed the lab and building had not been contaminated.