NEW ORLEANS -- Police are searching for a dump-truck driver who they said dropped a load of wet clay, causing a 22-car wreck inside the Harvey Tunnel, and then fled, WDSU-TV reported.

Twenty-four people, including a pregnant woman, were injured in the crash, which occurred about 1 p.m. Friday.

State troopers said the pregnant woman walked out of the tunnel and then went into labor.

It isn't known if the baby has been delivered, and the woman's condition is unknown.

Officials said none of the other injuries was serious. All 24 people injured in the crash were treated at West Jefferson Medical Center and all but one has since been released.

After the pileup, workers spent hours clearing wrecked cars and mud out of the tunnel.

Police said cars slid through the wet mud and slammed into the tunnel walls.