Authorities will be looking to speak to the driver of a road train that crashed on the Nullarbor Plain, who appears to have fled when the chemical tanker burst into flames.

A truck with two trailers flagged as carrying highly toxic chemicals was heading west when it crashed into the bush off the Eyre Highway on Monday.

A fire broke out almost immediately and took over eight hours to control.

A Department of Fire and Emergency Services spokesperson said the nearest water supply was an hour from the scene.

It was doused in foam overnight by Eucla Police wearing protective breathing gear, before a local was able to smother it using a front-end loader and sand.

Police say it is unknown just which chemicals were on board, but have estimated the cost of the damage at around $800,000.

The driver’s whereabouts were unknown when authorities arrived on scene, but some reports say they have now tracked him down.

Police were running with a theory that he was picked up by another truck driver heading towards South Australia.