A major fire broke out at a fish processing plant in the Kirk Square area of Peterhead.
Grampian Fire and Rescue Service was called to the incident at the Freshcatch premises in Kirk Street at about 1815 BST.
There were no reports of any injuries.
Smoke could be seen from a wide area, and the fire service urged the town's residents to remain indoors and to close windows.
Peterhead lifeboat was launched to rescue five youths who had used three inflatable dinghies to get closer to the seafront fire.
A spokesman for Aberdeen Coastguard said the youths had been picked up for their own safety after emergency services were alerted by a concerned member of the public.
He said the teenagers had been advised of the risk they were posing to themselves because of their proximity to the fire, and the fact that they were not wearing lifejackets.