User blog comment:EmpyreanSmoke/Supernatural Q&A/@comment-3976024-20150913082216/@comment-3481504-20150913224050


 * Castiel said, "No angel can pass or move through the flames, or he dies."

And seeing as none of the archangels tried to get out once trapped, the above statement he made was most likely true. Michael is the understandable exception, with him being the strongest angel in existence.