A deadly pileup on Interstate 55 near New Orleans, Louisiana, happened Monday when a “super fog” dangerously blanketed the roadway.

At least seven people were killed and numerous others injured during the incident, Fox Weather reported Tuesday.

An aerial photo shows the mangled vehicles as crews assessed the scene:

Louisiana State Police said Monday its officers and other first responders were searching for victims of the crash, which happened in St. John the Baptist Parish.

The agency continued:

Preliminary investigation revealed that at least 158 vehicles were involved in this morning’s crash. That total is from both north and southbound lanes. Seven (7) fatalities have been confirmed. Over 25 individuals were transported to area hospitals with varying degrees of injuries from critical to minor. Many victims sought medical assistance on their own.

A portion of the crash scene caught on fire shortly after the initial incident. One tanker truck carrying a hazardous liquid is being off-loaded due to a compromised tank/trailer. Once the tanker is removed, first responders will be able to better assess the vehicles in that immediate area. It is possible that additional fatalities could be located. Louisiana State Police asks anyone missing a family member who was traveling through the area this morning to contact Troop B at (504) 471-2775.

Per the Fox article, a super fog is made up of moisture and smoke from wildfires. When this occurs, it can significantly cut visibility.

“Because of fires burning in the region, the FOX Forecast Center expects low visibility to remain an issue during the next few mornings, which could lead to more dangerous morning commutes,” the outlet said.

Video footage taken at the scene shows the wrecked vehicles and the fog surrounding the area. It appears to have been recorded before the fire:

Officials have issued a Dense Fog Advisory spanning from Jackson, Louisiana, to the western part of New Orleans.

In an update Tuesday morning, state police said, “Troopers are in the process of removing the final group of vehicles.”

“Once that is complete, a surface cleanup of the area will take place. Following the cleanup, DOTD [Louisiana Department of Transportation and Development] will begin their assessment of any damage to the bridge,” the agency said. “I-55 North and South will remain closed until that assessment is complete.”