A 13-year-old boy has been arrested after a large fire that caused extensive damage to the visitor centre at the Frogmore Paper Mill in Apsley near Hemel Hempstead.
The fire broke out in a skip at around half past three on Saturday afternoon.
Hertfordshire fire and rescue sent thirteen appliances to the scene.
Roads were closed and local residents were advised to keep their windows shut.
The teenager has been released under investigation.
A spokesperson for Hertfordshire Police said: “It was reported that a fire had started in a skip, before spreading to a nearby building.
“Officers attended to put road closures in place while the fire service worked to extinguish the blaze. The road was reopened at around 5.50pm.
“It was deemed that the fire was started deliberately and investigations are continuing.
“A 13-year-old boy was arrested on suspicion of arson and has been released under investigation while enquiries continue.”
