Firefighters worked for more than two and a half hours to ensure that that blaze did not cause more damage and that it was not going to re-ignite.
The alarm was raised at 4.20am on land at the Maesbury Road Mile Oak Industrial Estate.
Fire crews from Oswestry and Ellesmere were quickly on scene along with specialist Hazmat officers after concern that products used on the biomass product may have added hazardous implications for the firefighting operation.
Cladding on an adjacent building was also affected and crew members wearing breathing apparatus went into the building to check that there was no fire inside.
A thermal imaging camera was used to check for hotspots.
The fire was under control by 7.08am.