Heat-resistant material (8)
I believe the answer is:
asbestos
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">heat-resistant material</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for asbestos that I've seen before include "Old fire-retardant" , "'Fireproof substance, dangerous to health (8)'" , "Fire-resistant material, a danger to health" , "Survivor of heat" , "Fire-retardant material" .)