(LOS ANGELES) -- At least seven firefighters were injured in a raging wildfire in southern California, officials said Wednesday night.
The Route Fire in Castaic has burned over 5,208 acres with 12% containment as of Thursday morning, the Los Angeles Fire Department said.
Authorities previously reported the fire at 4,600 acres and 0% contained as of late Wednesday night.
Of the seven firefighters that have suffered heat-related injuries, five were taken to the hospital for care, the Los Angeles Fire Department said.
"The folks out there are just taking a beating. We did have eight heat-related events today. Six people were transported. I believe their condition is all good," Los Angeles County Fire Department Deputy Chief Tom Ewald said at a press conference Wednesday.
Units were dispatched to the fire around noon Wednesday, when the fire was only about 60 acres, the Los Angeles Fire Department said.
As units arrived to the scene, officials closed the northbound Interstate 5 just before 1 p.m., with the southbound lanes closing shortly thereafter.
The major roadway was reopened, but two lanes remain closed at Templin Highway to Lake Hughes Road as of Thursday morning, according to authorities.
Fifteen aircraft, including three with night vision capabilities, were also used to fight the fire, which has destroyed two outbuildings and a truck, Ewald said.
Evacuations were ordered for Paradise Mobile Estates and all structures south of Templin Highway along Upper Ridge Route Road, authorities said. Residents in that area were ordered to evacuate to the north, according to the Los Angeles County Sheriff's Department.
The cause of the fire is still under investigation.
The Los Angeles County Police Department, which is working alongside the Santa Clarita Valley police, said its priority is to help assist with evacuations, be it people, livestock or vehicles.
There are currently two shelters available to residents, one in West Ranch High School and one in Frazier Mountain High School, officials said. Small animals can be taken to Castaic Animal Shelter.
The fire rages as southern California braces for a major heat wave this week, with much of the region under excessive heat warnings on Thursday. Los Angeles is projected to reach into the triple digits throughout the weekend, according to the National Weather Service.