How did "Liz" from Hellboy get fire powers?

Question

How did "Liz" from Hellboy get fire powers?

Answer 1

it's never explain how she got the power.

Answer 2

I watched the movie and if I remember correctly she gets fire powers whenever she gets angry.

I found this on internet:

"LIZ SHERMAN, voiced by Selma Blair

Liz Sherman was raised in Kansas City with a normal childhood until the onset of puberty at age 11. When teased by a neighborhood bully she became emotional which lead to a full manifestation of her pyrotechnic power.  The resulting fire leveled a city block, killing 32 people including her family.

Fire officials could not explain the source of the fire and Liz was shuttled through several foster homes.  There were several instances of unexplained fires centering on Liz.  Although there was no evidence of incendiaries, Liz was labeled as emotionally disturbed and the source of the fires until she became an official ward of the BPRD.

The Bureau helped her get control of her power to the point where she can do small things, like lighting a cigarette or starting a campfire with ease.  But larger tasks are still difficult.  Summoning the power within her is not the problem, it is the control of her extraordinary talent that becomes difficult.  Liz is not a fiery superhero; she is closer to a walking nuclear weapon.  When her control slips she becomes a danger to her friends and fellow agents.

Perhaps it was her treatment in foster care that instilled in Liz Sherman a distrust of authority figures.  She has run away from the Bureau thirteen times.  When she stays it’s because of the familial closeness she feels to Hellboy, Abe Sapien, Kate Corrigan and Professor Broom"

Answer 3

vally is correct.  In the strip (and you do read the strip, don't you?  Why not?) it's essentially established she was born with it.