Tractor-trailer crashes on the Southeast Expressway and then catches fire, closing southbound Route 93 in Boston.

The southbound side of the Southeast Expressway was shut down at the start of rush hour Thursday morning because of a tractor-trailer fire.

The truck crashed just before 6 a.m. at Neponset Street near Exit 12 in Dorchester. The fire was put out about 45 minutes later.

State police immediately closed the southbound side of Route 93.

One lane opened up just after 7 a.m., but there were major delays on both sides of the highway.

The southbound side opened up completely around 9:40 a.m.

According to the Boston Fire Department, there were no injuries.

There’s no word yet on what caused the crash.