Video of a large fire at a sausage factory showed thick plumes of smoke and flames rising from the building.
The blaze at Riverway Foods on River Way in Harlow, Essex, on Tuesday was being tackled by 10 crews from both Essex and Hertfordshire.
The fire service warned people to stay indoors and keep windows shut as smoke drifted across the town.
It said when crews arrived the building was 95% alight and 100% smoke-logged.
See video here: https://www.bbc.com/news/av/uk-england-essex-61232261