Florida ? About 70 vehicles crashed on an interstate blanketed by fog and smoke from a brush fire early Wednesday, killing four people, authorities said.

Nearly 15 miles of Interstate 4 between Tampa and Orlando was closed by several crashes, including the pileup. Aerial footage in the early morning showed the soupy mix of fog and smoke covering the landscape for miles and giving the sky an eerie golden color.

The poor visibility forced rescuers to walk along the closed interstate checking individual vehicles for injured motorists, Florida Highway Patrol Trooper Larry Coggins said. The conditions cleared in late morning, showing mangled, charred trucks and cars pinned underneath some tractor-trailers.

Workers were still trying to rescue one man pinned beneath an overturned truck. There is no estimate on when I-4, the main east-west artery for central Florida, will reopen.

Coggins said 38 people were injured, five seriously.