A Lisburn court was cleared on Thursday after it was suspected a canister of pepper spray had been released.
The Magistrate Court proceedings were adjourned for a time on Thursday morning after a substance caused dozens of people to suffer coughing fits.
Police officers told those present that they believed a canister of pepper spray had been released.
The court was evacuated and proceedings moved to another room in the building.
In a statement, a spokesperson for the Northern Ireland Courts Service said: “Court business was temporarily adjourned for a short period of time following the apparent release of a spray inside courtroom one of Lisburn courthouse.
“An investigation has now commenced into the cause of action.”