The country's most arsenic contaminated site has now been cleaned up, and reopened to the public.
The Prohibition Mine - a former gold mine at Waiuta on the West Coast - lay open for 60 years, with concentrations of arsenic at 5000 times the safe human limit.
The danger was discovered a decade ago. The Department of Conservation started cleaning up the site in August.
West Coast operations director Mark Davies said 96 barrels of highly arsenic-contaminated material were removed for treatment and disposal at a specialised facility.
"This area has a fascinating social and industrial history that we want visitors to experience, and the remediation is key to that. The site is now ready for us to develop a mining history experience that will complement our existing network of attractions such as Denniston and the Brunner Mine Site."
He said the clean up cost $2.6 million.
The processing plant operated from 1938 till 1951, when the mine closed and was abandoned after the mine shaft collapsed.