Sweeper Truck spills diesel on track in Sochi

[Scott]

Seriously    Someone probably knew, but didn't bother to tell anyone and they discovered it just before FP1, wasting much of the session cleaning it up.

http://www.autosport.com/news/report.php/id/121238

[Steve A.]

A bad Grand Prix, getting worse, would hate to think what would have happened if it wasn't noticed.

[John S]

These things happen, plenty of times over the years fluids have gone down on the track ahead of sessions.

We've even seen actual races started in Brazil and other places with large swathes of cement dust over parts of the track.

Before each session at any track the pace car, with an official to check the track is fit for running, does a lap - if they are not happy with anything the session is held up until remedial measures are undertaken; standard procedure.