Pirelli says an external cut into the tyre structure is the likely cause for the failure which sent Nico Rosberg into a high speed spin during practice for the Belgian Grand Prix.
Rosberg's tyre failed on the approach to Blanchimont and the German was sent across the track before coming to a rest in the run-off.
Following extensive investigations overnight, Pirelli is confident that there is no structural integrity issue with its tyres.
"We have conducted a thorough investigation to find out exactly what happened with Nico’s tyre," said Pirelli's Paul Hembery.
"This investigation now excludes any structural integrity issues. Based on the information and data available an external source of damage is the conclusion made."