Brian Gallaher, band director for Ocoee Middle School in Cleveland, was among those killed in a 9-vehicle crash on northbound Interstate 75 near the Ooltewah exit. He was in a 2010 Toyota Prius.

Also killed was Jason Ramos, assistant director of residential life at Dalton State. He was on his way home to Brunswick, Ohio, for vacation, traveling in a 2003 Mazda station wagon.

Sisters Savannah and Kelsey, eight and 10, were also among the fatalities. They were killed along with two other occupants of the same 2010 Toyota Scion. They were Tiffany Watts, 31, of Morristown, Tn., and Sandra Anderson, 50, of Rutledge, Tn. Ms. Watts was the mother and Ms. Anderson the grandmother of the girls. The two children were living in California with their father. This was the only vehicle in the wreck that caught fire. One woman from the Scion was ejected, and the others died in the fire.

Police said the tragic accident at Ooltewah on Thursday night was caused when a tractor-trailer slammed into eight vehicles stopped for a construction project.

The driver of the 2007 Peterbuilt semi was identified as Benjamin Scott Brewer, 39, of London, Ky. He and his female companion, Charity Dawn Pennington, 38, were not injured.

There were a total of 18 individuals involved. Six individuals were medically treated or transported to local hospitals, and six required no medical treatment.

Those with non-life threatening injuries were Marty Tumbleson and Charles Allen Daniels Jr. of Tennessee in a GMC Savana van, John and Nancy Stanley of Mississippi in a 2007 Chevy Highlander minivan, Ryan Humphries of Tennessee in a 2001 Ford F150, and Justin Knox of Mississippi in a 2015 Cadillac TS.

Also involved in the wreck with no injuries were Travis and Tina Close and their two minor children. They were in a 2015 Toyota Tundra.

There were multiple state, county and local agencies which assisted in the rescue efforts as well as the investigation. Victim services and the National Transportation Safety Board are also responding to assist. Investigators are working tirelessly to compile information and determine the cause of the crash, officials said.

The northbound lanes of the freeway were closed for almost 12 hours prior to reopening shortly before 7 a.m. Friday.

Officials said this is the largest number of fatalities the Chattanooga Police Department has seen in the past 10 years in a single motor vehicle crash. It is the largest number of vehicles CPD has reported in the past 10 years involved in a single motor vehicle crash.

· Over the past five years, the CPD jurisdiction of I-75 has only experienced one fatality.

Police Lieutenant Craig Joel said, "This is probably the most tragic motor vehicle crash I've seen in 20 years."

While the northbound lanes were closed, traffic was diverted to Cleveland along Old Lee Highway. Another route was along Highway 58 and then Highway 60.

The wreck was just past the northbound on ramp at Ooltewah.

Smoke was initially pouring from one of the vehicles.

The tractor-trailer had a smaller vehicle pinned against the center concrete barrier.

Nearby motorists, including those in the southbound lane, were splattered with flying vehicle parts at the time of the collisions.

Tami Chambers Beal said, "I came up on this accident after it happened. It was the worst accident I had ever seen. So many lives lost and so many people injured. I got down on my knees and prayed for all involved. I am still shaken by it. God bless them all."