Damage to Shoya Tomizawa's crank case cover caused the fluid spillage which caused mayhem on lap two of the Moto2 race at Jerez today.
The championship leader tangled with Simone Corsi and fell while fighting for the lead in Spain, with the unprotected crank cover smashing as it hit the ground and immediately depositing oil on the circuit at the Dry Sack corner.
Immediate pursuers Toni Elias and Julian Simon both crashed, as did a further six other riders who subsequently arrived on the scene.
"I crashed after the back straight and my oil was on the road, and many riders crashed," said Tomizawa. "I'm so sorry for the delay, and also because many riders crashed and they had to repair their motorbikes. I'm so sorry."
The race was red-flagged and restarted over a shorter distance, with Elias going on to win ahead of Tomizawa. All those involved in the oil crash were unhurt and able to take the restart.