SB 5.6.8

atha samīra-vega-vidhūta-veṇu-vikarṣaṇa-jātogra-dāvānalas tad vanam ālelihānaḥ saha tena dadāha.
Synonyms: 
atha — thereafter; samīra-vega — by the force of the wind; vidhūta — tossed about; veṇu — of bamboos; vikarṣaṇa — by the rubbing; jāta — produced; ugra — fierce; dāva-analaḥ — a forest fire; tat — that; vanam — forest near Kuṭakācala; ālelihānaḥ — devouring all around; saha — with; tena — that body; dadāha — burned to ashes.
Translation: 
While He was wandering about, a wild forest fire began. This fire was caused by the friction of bamboos, which were being blown by the wind. In that fire, the entire forest near Kuṭakācala and the body of Lord Ṛṣabhadeva were burnt to ashes.
Purport: 

Such a forest fire can burn the external bodies of animals, but Lord Ṛṣabhadeva was not burned, although He apparently seemed so. Lord Ṛṣabhadeva is the Supersoul of all living entities within the forest, and His soul is never burned by fire. As stated in Bhagavad-gītā, adāhyo ’yam — the soul is never burned by fire. Due to Lord Ṛṣabhadeva’s presence, all the animals in the forest were also liberated from material encagement.