LONDON, England - The 2013 British Grand Prix tyre fiasco plunged Formula 1 into crisis and triggered talk of a possible drivers' boycott at the German GP on July 07.Tyre supplier Pirelli, criticised by teams since the start of the 2013 season, began an immediate investigation after four drivers suffered left-rear tyre failures at Silverstone.Ferrari's Felipe Massa, almost killed by debris shed by a car in front of him at the 2009 Hungarian GP, would not rule out a driver boycott if solutions were not in place for the Nurburgring race.'WE DON'T WON'T TO BE KILLED'He suffered one of the blowouts.Massa said: "I don't want to say that (drivers would walk out) because I don't want to create loads of problems but this is something that for our safety we can do."McLaren's Sergio Perez, another victim of the exploding tyres, said drivers were risking their lives and needed assurances.Perez said: "If something like this happens again we don't want one of us to be killed."Mark Webber, second for Red Bull in the race, said it had been like Russian roulette and he had been praying for a pace-car because nobody knew who would be next.'NOT TIME TO POINT FINGERS'Perez's team principal Martin Whitmarsh warned that driver action could not be ruled out: "I think there's that danger (of a boycott), and rightly so. If the drivers and the teams can't be convinced that they can do so (race) safely, then they would have to resort to that."That's not what we want for F1. We've faced some of these issues before. We had it in Indianapolis and that was terrible for the sport."He was referring to the 2005 US GP in which only six Bridgestone-shod cars started after problems with the Michelin rubber.Whitmarsh said: "We've really got to work together. This is not a time to point fingers. It's a time to work together, find the solution, get on with it."Whitmarsh expected something to change before cars appeared on track again in Germany and McLaren was not considering any drastic action at present.NEW PROCESSThe immediate question is whether the problem was track specific, with failures caused by debris or a particularly sharp kerb at Silverstone cutting into the tyres, or something related to the construction and design.Pirelli's motorsport director Paul Hembery said the tyre supplier ruled out the cause being linked to a new bonding process introduced ahead of Silverstone. He will join a meeting of F1's sporting working committee, although teams will want to see something tangible before then.Pirelli had wanted to make more fundamental changes but needed the unanimous agreement of teams and some - notably Ferrari, Lotus and Force India - have objected because their cars are working well with the tyres.The 2013 tyres have a high-tensile steel belt under the tread, designed to make it hard for objects to penetrate and cause a sudden deflation, whereas the 2012 versions used a Kevlar belt.'WE WERE LUCKY'The new bonding process was meant to preventing more of the embarrassing "delaminations" experienced at previous races where the tread peeled away when penetrated by debris but the main body of the tyre beneath the belt remained inflated.Red Bull boss Christian Horner and Whitmarsh each suggested reverting to the harder 2012 tyres for Germany but the calendar is not on F1's side and substantial change may have to wait until Hungary at the end of July.A stop-gap solution might be to impose mandatory tyre pressures but that would be difficult to police, given the competitive advantage at stake.McLaren's Jenson Button said: "If we keep these tyres we will have a safety issue. We were lucky that nothing worse happened."Five tyre explosions, whether it is from debris or a tyre failure I don't care. The result is still the same and the danger is the same. The issues are plain to see. We are not going to let that go."