Collocations for fatal - adj.

be, prove

nearly (esp. AmE)
He has not driven since his nearly fatal accident earlier this year.

always, invariably
often, sometimes, usually
rarely
possibly, potentially
a possibly fatal setback to his plans
The disease is potentially fatal.

for
This kind of accident is almost always fatal for the pilot.

to
a chemical which is invariably fatal to small mammals

be, prove

absolutely
ultimately
Her disregard of this advice was ultimately fatal.

to
Tax increases have proved fatal to the nation's business community.

Fatal is used with these nouns:
accident, attack, attraction, blow, complication, consequence, crash, disease, dose, error, flaw, haemorrhage, heart attack, illness, incident, injury, mishap, mistake, outcome, overdose, poisoning, shot, side effect, smash, sting, stroke, weakness, wound