Tafsir of At-Takweer 81:12

And when the Hellfire is kindled—that is, it is fueled with an intense kindling. Qatada said: "The wrath of Allah (Exalted is He) and the sins of the children of Adam kindled it." A group among them, including Ali (may Allah ennoble his countenance), read it as su‘irat (kindled) with the takhfif (lightening of the shaddah).