Police and fire investigators say the fire that destroyed the Alexandra Wastebusters on Thursday was arson.
They've pinpointed where the fire started and have determined it was deliberately lit.
Detective Alan Lee said a criminal investigation is underway, and they are appealing for anyone who has information to come forward.
He said anyone who was in the Boundary Road industrial area between 6pm and 8pm that night should contact the local police station.
He said the loss of the recycling services facility is a devastating blow to both the organisation, and the wider Otago community.
Take your Radio, Podcasts and Music with you