Authorities released photos Tuesday afternoon of the aftermath of the mayhem.
A room was damaged and covered in a fine white powder that came from the fire extinguisher, which ended up on a podium. More photos show the chaotic scene outside as people were put onto stretchers. Some were given oxygen.
It all started just after 8:00 a.m. Tuesday when 29-year-old Thomas McHugh of Drexel Hill, Pennsylvania was released from police custody inside the building in the 2700 block of Atlantic Avenue.
Somehow, police say, he made it up to a fourth floor restricted area where he was confronted by officers who reported that he was rambling on incoherently.
Police say he grabbed the fire extinguisher and sprayed three officers in the face.
"They're wrestling with this guy and finally get him in custody," said Atlantic City Police Sergeant Monica McMenamin. "The whole floor, the whole length of the floor, was white smoke. And it started getting into the HVAC system, so the building was evacuated."
As many as 14 people, including six police officers and three city employees, were taken to AtlantiCare Regional Medical Center, where they were treated and released for skin, eye, and respiratory irritation.
McHugh was subdued and taken there as well for a psychiatric evaluation.
McHugh was once a standout football player at Monsignor Bonner and went on to play at Penn State. But 10 years ago he was dismissed from the team after an arrest for public drunkenness and harassment.
His uncle, Don Meyers, told Action News that McHugh suffers from mental health problems and had been off his medication.
Speaking in Drexel Hill Tuesday afternoon, Meyers apologized for the trouble his nephew caused.
"Hopefully everything can be reconciled somehow and he can get the help he needs and that everybody's okay down there," said Meyers. "We're sorry that it happened and that other people had to be involved with it. Sometimes these things get like this."
Police say McHugh had been arrested twice on Monday for two separate charges - disorderly conduct and shoplifting. He was in the holding cell area overnight and then released Tuesday morning.
He now faces charges including aggravated assault and is being held on $100,000 bail.