All emergency services were called to Carlsberg brewery in Northampton following another ammonia leak.
A spokeswoman for Northamptonshire Police said: “At 9.23pm yesterday (July 23), Northamptonshire Fire and Rescue Service responded to an ammonia alarm sounding at the Carlsberg brewery site in Northampton.
"Fire Service personnel worked with on-site engineers to assess and confirm that the levels of ammonia were safe.
"A number of Carlsberg employees were given precautionary medical checks by on-scene ambulance crews before returning to work.”
The 45-year-old was working at the firm’s site in Northampton in November, 2016, when he was exposed to ammonia.
After eight days, an inquest jury reached a conclusion of accidental death but also concluded that the ammonia leak was preventable.
David, of Bridgnorth, Shropshire, who was employed by Speedrite, was contracted to work at the Carlsberg brewery. He was helping to remove a dormant compressor unit on 9 November, 2016, when a disconnected valve blew, engulfing the room in ammonia.
Back in November a total of 22 people including 11 factory staff, two police officers, and nine firefighters were taken to hospital following the incident.
A Carlsberg spokesman said: “At approximately 9.20pm last night (Monday 23rd July) local emergency services were alerted to an ammonia alarm that had been triggered at the Carlsberg brewery on Bridge Street, Northampton. All staff on site were immediately evacuated from the site, and the emergency services attended the scene. Whilst some employees received health checks on site by paramedics- no admissions to hospital were necessary, and all employees are safely accounted for. The emergency services left the site at approximately 11.30pm
"It is too early to speculate on the cause of the alarm, and we are of course cooperating fully with the emergency services and other agencies whilst the incident is being investigated.
"The site is now being returned to normal operation during to course of the day. We’d like to thank the emergency services for their prompt response to this alarm and dealing with the incident with such professionalism."
A spokesman from the East Midlands Ambulance Service said: “We received a call at 9.15pm on 23 July to Carlsberg Factory in Northampton town centre following reports of an industrial incident involving chemicals. We sent two paramedics in ambulance cars, two crewed ambulances and our Hazardous Area Response Team, and eight patients were treated at the scene for minor injuries.”
A Health and Safety Eexecutive spokesperson said: “HSE is aware of the incident and making initial enquiries.”