Live posts via Twitter, from 12:50 to 5:50 p.m.:

• CHP has shut down northbound Interstate 5 near the Grapevine after a multi-vehicle crash. There are at least 15 patients.

• Officials have stopped traffic at Fort Tejon. There are four patients with major injuries, three others are good.

• A Hazmat crew is also being called to inspect the big rig's load. The rig was involved in a crash.

• Officials are on their way to their offices to get more cones.

• All traffic is stopped. The crash involved an overturned passenger van. Up to 15 people before the van burst caught fire.

• The crash scene is at just north of the Fort Tejon truck escape ramp on the east side of northbound Interstate 5, according to CHP.

• There are two children with minor injuries, and a man also with minor injuries, according to Kern Fire Department scanner traffic.

• Officials are diverting traffic at Fort Tejon. Five vehicles and a big rig are involved. Some possibly went over the center divider.

• Kern County Fire is requesting two air ambulances to the crash site. Traffic is completely congested, according to scanner traffic.

• Equipment and officials from Los Angeles are being brought in to assist, including a air ambulance.

• Count: One big rig and nine vehicles are involved. Five people have major injuries and six have moderate injuries.

• Officials are unable to tell if any vehicles went over the side of the center divider because of fog, according to CHP.

• Scanner traffic: Medical helicopters from Ventura and Los Angeles will not be able to fly anyone into Bakersfield, only to hospitals south.

• Two medical helicopters estimated time of arrival at the crash site are 10 and 20 minutes, respectively.

• Detour signs have been placed. Traffic is being diverted to eastbound Highway 138 and Highway 14.

• Caltrans is setting up a closure at Interstate 5 near Highway 138 to detour drivers, according to CHP.

• Scanner traffic: Disturbance on Seventh Street. Subject threw a broom at the caller's vehicle.

• The fire department has cleared the load on the big rig. Hazmat crews have been canceled.

• The cargo on the big rig is "corrosive liquid." It's toxic if inhaled or if put in contact with skin, according to CHP.

• Traffic is backed up more than 15 miles from the crash site to Quail Lake, according to CHP.

• Crash victims taken to hospitals: 2 to Memorial, 2 to Bakersfield Heart, 2 to Mercy Southwest, 3 to LA County and 1 to Henry Mayo.

• Officials are starting to let a group of traffic through just south of the crash site. All lanes will be opened shortly, according to CHP.

• Officials are still clearing lanes. They are not yet fully open, according to CHP.

• Roadway is clear except for one vehicle on the right hand side. Officials are escorting it down the Grapevine.

•  Traffic is moving northbound now in the Newhall area from Highway 138.

• All lanes are now open but California Highway Patrol is pacing traffic because of the fog in the area.