Conservation groups in two states say the Army Corps of Engineers needs a South Carolina pollution permit now, not later, for the $650 million deepening of the Savannah River shipping channel.
Attorneys late Tuesday filed a response to a corps request that a federal judge dismiss their lawsuit against the project.
The corps contended the conservation groups have not been harmed and the case in premature.
But attorneys for the groups in Georgia and South Carolina say people don't have to wait until environmental damage to occur before they try to prevent it.
The lawsuit alleges a South Carolina pollution permit is needed because deepening the shipping channel will dredge up toxic cadmium.
It contends the material will be dumped on the South Carolina side of the river.