At least 50 cars and their occupants plunged more than 60 feet into the Mississippi River when Minnesota’s I-35W highway bridge collapsed at just after 6 p.m. Wednesday.

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Emergency rescue workers toiled feverishly overnight to remove victims who were trapped in cars and pinned underneath the tons of concrete and twisted steel that once comprised the 1,950-foot-long bridge.

Five people have been confirmed dead, but there are reports of people still trapped in cars submerged under water. Seventy-nine people are reported injured and many are still missing.

Many more injuries and possibly many more deaths can be expected with this type of catastrophe, said Dr. Manny Alvarez, managing editor of health for Foxnews.com.

“In this type of accident there are several types of injuries,” said Alvarez. “You have your typical lacerations and broken bones from twisting metal and glass breaking.”

Dr. Joseph Clinton, emergency medical chief at Hennepin County Medical Center, said his hospital treated 28 injured people — including six who were in critical condition.

Clinton said at least one of the victims had drowned.

Alvarez said he spoke to one doctor at the county hospital Thursday morning who told him that many of the victims were being treated for head and back trauma.

In addition to drowing concerns, people who plunged into the Mississippi River Wednesday also may have suffered respiratory damage because fresh water, like that found in rivers, can cause significant lung trauma if it is not immediately monitored and treated, Alvarez said.

Victims who were pinned inside their cars could be gravely injured.

“Those trapped likely suffered compression or crush injuries,” Alvarez said. “In crush injuries, often limbs are so severely damaged that they are impossible to repair and amputation is necessary.”

Many victims will suffer blood loss and be in need of transfusions.

“You also see damage to major vessels in crush injuries,” Alvarez added. “In this case, there is a lot of blood loss and it is necessary that rescue workers be prepared to remove and immediately resuscitate the victims because time is of the essence. The quicker you act, the more likely you are to save people.”

The Associated Press contributed to this story