The blaze started on Friday afternoon at The David Wood Foods Bakery site in Crackley Way, off Peartree Lane near Netherton, shortly after 12.05pm.
More than 100 firefighters were in attendance at the height of the blaze, with fire crews at the scene for four days, extinguishing the fire and trying to prevent a dust explosion which could have injured responders at the scene.
West Midlands Fire Service has now confirmed that the fire is out and that investigators have confirmed the fire was accidental. Firefighters managed to prevent the blaze spreading to nearby businesses.
Drone operators continue to work at the scene, to monitor for any hotspots and re-ignition. One fire engine is still in attendance, and fire crews are likely to be making precautionary revisits throughout the day.
Simon Barry, assistant chief fire officer, said: “This was a complex, challenging and potentially dangerous incident, to which our crews at the scene and several support teams responded admirably.
“Clearly, the impact on the business and its employees has been devastating. Our firefighters faced multiple risks as they battled to bring the fire under control and to prevent it spreading.
“They successfully contained the fire to footprint of the original building on fire and worked tirelessly to prevent a number of flour silos on the site being compromised.
“We were focused on preventing a ‘dust explosion’, which could have injured responders on site and affected nearby businesses.
“There was also ammonia on the site, but our work ensured that any risk from this was also successfully controlled.
“We also stopped the fire spreading to neighbouring businesses – one of which was only a metre away - and tons of paper and wood stored very nearby.
“When faced with such a large and developing fire, we continually assess and review the risks and our operational priorities. The safety of our crews and other responders is paramount.
“We also need to secure and maintain our water supplies for firefighting. In this case we needed to use our high-volume pumping unit to draw thousands of litres a minute from a nearby canal.
“We evacuated people from the nearby industrial estate, and had contingency plans in place in case we needed to move people out of nearby homes. Staff have since been allowed to re-enter nearby businesses.
“The hard work of crews and resources on the ground was complemented throughout by our team in fire control, who coordinated our initial response and ensured that we could resource this incident and any others that happened.
“A number of other specialist teams were also involved, and we worked closely throughout with several other agencies such as police and ambulance, the local council, the Canals and Rivers Trust and local health officers.”