Emergency services are at the scene of a reported ammonia leak in Burton Latimer.
Four fire appliances and 15 firefighters are at Latimer Business Park in Altendiez Way after the incident at about 4.40am this morning.
Soya food and drink manufacturer Alpro has been named locally as the source of the leak.
It's understood all Alpro employees have been evacuated from the site.
A spokesman for Northamptonshire Fire and Rescue service said the incident was contained and that there was no risk to the wider public.
The spokesman added that there were no reported injuries.
Nearby roads were closed but have since re-opened.
Fire crews are expected to be there for several hours.
An Alpro spokesman said: “At 3.19am this morning, our systems detected the presence of a high level of ammonia in the site services area at our Burton Latimer factory.
“The Alpro staff who were on-site were immediately evacuated, with no injuries reported. Following our well-established procedures, we called Northamptonshire Fire and Rescue.
“The incident has been fully contained, with no risk to employees and the wider public.
“We have found the leak, isolated it and will restart production soon. We will be working closely with the authorities to investigate how this incident occurred and can be avoided in the future.”