KAILUA-KONA » It could cost Hawaii island an additional $600,000 to prevent the spread of invasive little fire ants in mulching operations.

The Hawaii County Council Finance Committee on Tuesday unanimously advanced the county administration’s request to solicit up to $2.4 million in contracts annually, West Hawaii Today reported Wednesday. The action would apply to operations that would turn green waste into mulch at county landfills in eastern and western parts of the island.

The county is planning a different course from the $1.8 million current contract, which expires Dec. 31.

Under the new approach, the county plans to test a method to kill little fire ants by creating rows of green waste and turning them as the organic matter breaks down. That method would create heat necessary to kill the ants.

"We see this as a step in the direction of a compost operation," said Greg Goodale, head of the Solid Waste Division.

Worries about spreading invasive species have prevented the county from trucking mulch and green waste across the island. Property owners in west Hawaii particularly have concerns about fire ants and coqui frogs hitchhiking to their side of the island on green waste from the east side.

"I know there’s been less participation on the west side, but there’s still a great deal of concern or fear," said Council member Margaret Wille.

The Kohala-based councilwoman wanted to expand the program to three locations to give residents access to semi-digested mulch.

Goodale, however, said the lack of fresh water at the Puuanahulu landfill would greatly increase the cost. According to Goodale, the technology should be proven before it is expanded to the county’s west, south and north regions.