The man responsible for 640 litres of hydraulic oil spilling into the Waikato River has come clean to say he is "deeply sorry".
Property manager Steve McLennan, a former Hamilton city councillor, blew the whistle on himself after learning that a plumbing malfunction in the Tower Building on Ward St caused the oil spill on Saturday morning.
Mr McLennan manages the building on behalf of its owner, Waiheke Island farmer Chris Reeve.
A member of the public notified the Waikato Regional Council after seeing a large oil slick flowing into the river near Claudelands Bridge from a stormwater drain.
Mr McLennan yesterday apologised to the city council, regional council and visited the Waikato River Authority office to apologise, as well as emailing the 30 tenants of the building.