The Georgia Ports Authority wants to enter a federal lawsuit challenging the $650 million deepening of the Savannah River shipping channel.
The authority also wants to block the Savannah River Maritime Commission, a South Carolina state agency, from being involved in the case.
U.S. District Judge Richard Gergel on Thursday gave parties in the case until Aug. 6 to respond to the Georgiaports motion.
The suit filed by environmental groups says the U.S. Army Corps of Engineers needs a South Carolina pollution permit before the project can start.
The suit alleges toxic cadmium from river silt will be dumped on the South Carolina side of the river.
Maritime interests want the channel deepened to handle larger ships that will routinely call in Savannah when the Panama Canal is deepened.