Delays on M25 after two lorry fires close motorway
National Highways said the lorry between junctions 27 and 26 was "well alight" when emergency services arrived but had since been put out.
"The lorry shed a significant load across the carriageway, which we expect to take some time to clear," a spokesperson said.
It warned drivers to expect delays in the area.
Essex Police was also at the scene and said: "We know this will cause disruption, but this is important work and we'd urge motorists to find alternative routes."