Did leaking gas intoxicate the london bombers?

The bright side, so far, of several failed attacks in London, is that the attackers seem incompetent and undersupplied. I wonder, reading this description, if the primary bomber failed because s/he was intoxicated by leaking petroleum fumes:

Scotsman.com News - UK - Second car bomb 'aimed at rescuers':

THE terrorists who attempted to bomb central London last week deliberately placed the second vehicle to catch rescuers attending the injured from the first explosion, Scotland on Sunday can reveal.

The senior security source also said the primitive gas and petrol devices were most likely the work of determined terrorists struggling - because of the security crackdown - to get their hands on the ingredients needed to create high explosives.

Yesterday, a huge police manhunt was under way for the terrorists responsible as forensic experts continued to examine the vehicles involved for clues.

The attack was thwarted after fumes were spotted leaking from the first vehicle, parked outside the packed Tiger Tiger nightclub in London's West End in the early hours of Friday morning...