Three people were exposed to potentially toxic fumes following a suspected chemical incident on an industrial estate.
The incident, which happened at around 10pm on Monday, saw fire crews from Thetford, Kings Lynn, and Norwich, along with other emergency services attend the scene on Brunel Way, Thetford.
Police said they were called due to concerns for the safety of occupants of the unit.
A spokesman said: “They believe the chemicals have been mixed incorrectly causing some fumes at a premises on Brunel Way.
“Three people were exposed to these fumes in total. We were told as a precaution in terms of evacuation.”
Norfolk Fire and Rescue cordoned off the affected area and evacuated people from within the unit.
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