Simon Coveney, whose department is due to apply to the Environmental Protection Agency this week for a licence to operate the former Irish Steel/Irish Ispat site as a landfill, also warned that digging out the site could cause more environmental damage.
The proposed solution is the “optimum environmental solution”, he said.
“That is the only agenda here. This isn’t a minister deciding what’s the best thing to do here and hoping we’ll get permission. EPA has been involved in assessing the various options. Cork County Council, operating as an agent on behalf of my department, has put the best solution in place for making this site safe.
“This has been an environmental and visual scar in Cork Harbour for many, many decades. And we are going to put that right now.
“It you start digging out that island, you may do an awful lot of damage from an environmental point of view than by the course of action we think is the right course of action.”
He was responding to concerns that most of the waste material dumped on the island — byproducts of the steel-making process — will simply be buried under several layers of membrane as part of the site remediation project.
However, he said the most hazardous materials — including the deadly carcinogen chromium 6 — will be removed before the “inert material” is covered by membranes and buried with topsoil.
The council lodged a planning application with An Bórd Pleanala two weeks ago to transform the island into a 13-hectare public park.
Material dumped at the East Tip section of the island will be capped and an “engineered structure” will be installed around the perimeter of the dump before the park is developed.
The finished park will include a 3km circuit for walking and running, grasslands, wetlands, bird viewing areas, bird roosting ledges, and car parking.
Mr Coveney said he hopes to have positive decisions from both applications within a few months, with hopes that physical work could start next summer.
A detailed assessment of the site by environmental experts last year found the site poses “no legacy risk”.
Their studies found that the contaminated sludge and flue dust from the former steel works, which make up a third of the landfill, is not a public contamination hazard because it is mixed with other waste.