A bill aimed at prohibiting a process known as "enhanced geothermal" has received the initial support of the Hawaii County Council.
The Hawaii Tribune-Herald reports the council must vote on the bill one more time. On Wednesday it voted 7-0 in support after amending the legislation to increase penalties.
With enhanced geothermal, fluids are injected deep in the earth to widen cracks in order to increase permeability. That allows more underground heat sources to be reached.
The bill was drafted to prohibit enhanced geothermal though it would apply to all forms of hydraulic fracturing or fracking.
No geothermal companies have publicly stated any intent to use enhanced geothermal in Hawaii.
But bill supporters say the ban is needed to err on the side of caution.