Blended fuel escaped, dispersing a lead from petrol (9)
I believe the answer is:
coalesced
'blended' is the definition.
('coalesce' can be a synonym of 'blend')
'fuel escaped dispersing a lead from petrol' is the wordplay.
I cannot quite see how this works, but
'fuel' could be 'coal' (coal is a kind of fuel) and 'coal' is present in the answer.
'from' could be 'e' (I've seen this in other clues) and 'e' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for coalesced that I've seen before include "Mixed" , "Came together as one" .)