Five people were taken to hospital after a suspected gas leak at an Amazon warehouse.
Emergency services were called to the site just off the A1 near Bowburn, in Durham, at around 10.30am on Saturday.
It is understood staff were ordered to evacuate the premises whilst safety checks were carried out.
A spokesperson from the North East Ambulance Service said: "We were called yesterday at 10.35am to reports of people unwell at an Amazon warehouse in Bowburn.
"We sent three of our Hazardous Area Response Teams and two additional resources, and we took five patients to the University Hospital of North Durham."
The current condition of the five patients has not been disclosed, nor the initial nature of their illness.
An Amazon spokesperson said: "We can confirm the site was evacuated yesterday but is fully operational today."
And County Durham and Darlington Fire and Rescue Service confirmed they attended the scene.
A spokesperson said: "We attended at 10.38am and no longer have appliances at the scene."
