Firefighting efforts remain ongoing and police and ambulance are also in attendance but there are no reported casualties.
The public is requested to continue to avoid the area and advised to keep windows and doors shut.
Update (6.00am)
Firefighters have worked through the night to bring the fire at M&H Plastics in London Road, Beccles, under control.
A Stop notice was issued at around 11pm last night and crews have been carrying out hot-spotting to identify pockets of fire.
An investigation into the cause is now underway.
The number of appliances required was reduced overnight and there are currently six crews in attendance.
The fire has completely destroyed one industrial unit at the site, severely damaged another while a third has suffered moderate damage.
This remains a live fire scene and the public is asked to continue to avoid the area, but it is no longer necessary for residents to keep windows and doors closed.
Update (15.9.26 at 2:21pm)
Fire Investigation Officers have been on scene. Throughout the morning, crews continued to damp down hotspots using an aerial ladder platform as the only available access was from above the building.
At around 1pm all fire service assets were released from the incident.
A reinspection will take place at around 4pm this afternoon.
Update (16.9.26 at 11:10am)
A reinspection yesterday evening discovered a flare up from the pre-existing fire. Firefighters used one hose reel jet and a thermal imaging camera. Structure remains unstable so access is a challenge for our crews.
Firefighters from Beccles and Lowestoft South were on scene for the next few hours to extinguish the fire and dampen down hotspots identified. At 8:05pm, the site was handed over to site security and the responsible managers, with reinspection planned for 6am in the morning. Crews asked security to call if any concerns.
At 9:23pm, a security guard from the site called to report re-ignition. Upon arrival, a crew from Beccles fire station discovered a small outbreak in close proximity of a diesel tank and two persistent hotspots. One extinguished, the second deep seated and inaccessible.
Site left with security and responsible manager shortly after 11pm with instruction to call fire service if required. Reinspection at 8am on 16.9.26.
At 8:06am on 16.9.26, a crew from Lowestoft South arrived for reinspection and discovered hotspots remained. One main jet in use to damp down.
At 9:26am, crews checked Units 17 and 18 - no sign of fire. The unit affected (19) was handed back to the site with security providing a fire watch.
11:26am: No further updates.