A fire that started on November 10 is still burning.
But the blaze on the border of Hemel Hempstead and St Albans, which forced the closure of roads as smoke made driving dangerous, is now under control.
It is not known how the fire at the recycling centre in Appspond Lane, Potters Crouch, started among the massive pile of wood waste that could be seen from the M1.
Herts Fire and Rescue Service spokesman Jo Brown said: “The fire is still burning but is very much under control and it has been left to the site staff to monitor on a continuing basis. Fire and rescue visit the site at least once a day to liaise with site staff and ensure the fire is progressing as expected.”