Appliances from Cosham, Fareham & Southsea were called to a large industrial blaze at 05.28pm.
Firefighteres have been dealing with a fire on an industrial unit at Castle Trading Estate, Portchester.
Firefighters arrived to see a factory unit ablaze.
Crews used breathing apparatus, Jets Hosereel & PPV Level 3 to clear smoke from the unit.
A full fire investigation is now underway.