Monaco Grand Prix organisers have strengthened the welding of drain covers around the circuit in a bid to ensure a repeat of Jenson Button's incident doesn't happen again.
The circuit, which is run on public roads, features various drain covers which are welded down for the race to ensure they don't lift and cause damage to cars during the race weekend.
However on Thursday during practice, a cover came loose when Nico Rosberg ran over it. Jenson Button, as the following car, ran into it, causing substantial damage to his front-wing and floor.
All the drains were inspected after the session, with FIA safety delegate Charlie Whiting confirming a 25cm square inspection hatch had come loose and cracked, despite having been welded in four places.
On Friday morning, those deemed vulnerable were re-welded to ensure there could be no repeat of the Button incident.
Speaking about the incident, Button's team-mate Fernando Alonso said: "It's never acceptable when there is an incident like this.
"It's something that we didn't take care of enough before practice in terms of circuit checks, in terms of the FIA, and everyone has to go into the details to make sure everything is safe to run."
