An ammonia leak in a Spalding abattoir resulted in six casualties being treated at the scene by paramedics.
Two members of staff were also taken to hospital.
The incident happened at Morrisons abattoir in Brunel Road, Pinchbeck, this morning.
Emergency services were called to the scene at 9.32am.
Firefighters helped with the evacuation of the building.
Breaking news 11am: Lorry loads of livestock were left waiting in a queue outside a Spalding abattoir after an incident this morning.It is not yet known what happened to cause the hold-up at Morrisons’ abattoir in Brunel Road, Pinchbeck, around 11am, but the Lincolnshire Free Press saw two fire engines and an ambulance leave the scene and staff had been evacuated.
A witness said Enterprise Way was also cordoned off for a short time.
One lorry driver said: “We don’t know what is going on. I’ve been here an hour and want to know if they are shutting up shop for the day.”