Five people, including two firefighters, were taken to hospital after a chemical spill at an industrial site in Co Down.
The Northern Ireland Fire Service received a call at around10.30pm last night about the incident at Leprino, a cheese factory near the village of Magheralin.
Seventeen people were assessed at the scene by ambulance services, with five transferred to hospital.
All have since been discharged and none of their conditions were described as life-threatening.
The factory was open for business today.
The Northern Ireland Fire & Rescue Service (NIFRS) said: "Four fire appliances and a command support unit attended the scene along with a number of emergency ambulances, a hazardous area response team, a doctor and PSNI," it said.
"The Northern Ireland Ambulance Service declared a major incident as a result of 17 people having to receive treatment.
"Of the 17 people treated, five were transferred to hospital which included two firefighters.
"All have since been discharged."
It added: "There was no risk to the public beyond the site, however NIFRS implemented a precautionary 100-metre exclusion zone.
"The incident was brought under control in conjunction with the site operator and all emergency services left the scene at 4.50am."
