West Sussex Fire and Rescue Service said it was alerted to 'reports of a fire’ at Lyons Farm Retail Park, shortly after 6pm, on Wednesday (June 4).
Video footage showed a security fog system had been activated at the Boots store.
A spokesperson said: "Joint Fire Control sent two fire engines from Worthing to the scene.
"Upon arrival firefighters carried out investigations and found that it was a false alarm, caused by accidental actuation of the security fog system."
Video: Sussex News and Pictures
