CHARLESTON, S.C. (AP) -- Another South Carolina agency wants to enter the federal lawsuit challenging the $650 million dredging of the Savannah River shipping channel.

The state Department of Health and Environmental Control says it should be allowed to participate because it would have to issue a Pollution Control Act permit for the dredging if the court requires one.

The suit was brought by environmental groups who claim a permit is needed because dredging the river to deepen the channel will mean toxic cadmium will be dumped on the South Carolina shore.

Last month, U.S. District Judge Richard Gergel agreed that both the South Carolina Savannah River Maritime Commission and the Georgia Ports Authority could also enter the case.

Gergel also appointed former South Carolina Congress John Spratt to mediate the suit.

AP-WF-09-04-12 1855GMT