Ten fire engines were dispatched to the scene in Whitstable Harbour, with fire crews making “steady progress” to extinguish the blaze.
Thick smoke can be seen rising from the scene, with several public transport services diverted in the area.
Local residents have been advised to stay away from the immediate vicinity and keep all doors and windows shut.
A spokesperson for Kent Fire and Rescue Service said: “Kent Fire and Rescue Service remains at the scene of a fire at a commercial premises in Whitstable Harbour.
“Ten fire engines and a height vehicle are in attendance, and crews are making steady progress, using hose reel jets and compressed air foam to tackle the fire.
“Anyone living or working nearby is still advised to keep windows and doors closed as a precaution due to smoke, and to avoid the area where possible while the emergency services deal with the incident.
“Please share this message with anyone who may not have access to the internet, thank you.”
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