Drivers were being advised to avoid the M11 near Stansted airport after two HGVs crashed.
A Royal Mail lorry and car transporter collided between junctions 10 and eight southbound at around 4.45am on Thursday, causing both to set on fire.
One lorry went up in flames on the hard shoulder, while the other was down an embankment – leaving fire crews with limited access.
Both drivers suffered minor injuries.
The hard shoulder fire was put out by the Essex County Fire and Rescue Service (ECFRS) but firefighters continued to work on the other after it kept reigniting.
The service told the PA news agency the fire was under control and officers were focused on monitoring hot spots and any reignited flames.
The ECFRS said in a statement on Thursday morning: “Firefighters are working to extinguish a lorry fire.
“Due to the lorry being down an embankment with difficult access, crews are working to remove the lorry to extinguish the fire.
“Once removed from the embankment, crews will work to extinguish the fire.
“Crews are also working to recover another lorry and make the scene safe ready for resurfacing works to take place.”
Drivers were urged to continue to avoid the area, where fire crews were set to remain for several hours to make sure it is safe.
A video taken by a passerby showed several burnt cars on the transporter.
It also showed smoke coming from the embankment on the side of the motorway.
National Highways South-East said a full closure was still in place, though trapped traffic had been released.
Some 250 metres of hard shoulder on the southbound carriageway was assessed and lanes one and two need resurfacing before the road can reopen, officials said.
It will reopen at 5am on Friday, after the HGVs have also been removed.
