The Jargon File (version 4.4.7, 29 Dec 2003):

asbestos cork award
 n.

    Once, long ago at MIT, there was a flamer so consistently obnoxious that
    another hacker designed, had made, and distributed posters announcing that
    said flamer had been nominated for the asbestos cork award. (Any reader in
    doubt as to the intended application of the cork should consult the
    etymology under flame.) Since then, it is agreed that only a select few
    have risen to the heights of bombast required to earn this dubious dignity
    ? but there is no agreement on which few.


The Free On-line Dictionary of Computing (30 December 2018):

asbestos cork award

    Once, long ago at MIT, there was a flamer so
   consistently obnoxious that another hacker designed, had made,
   and distributed posters announcing that said flamer had been
   nominated for the "asbestos cork award".  (Any reader in doubt
   as to the intended application of the cork should consult the
   etymology under flame.)  Since then, it is agreed that only
   a select few have risen to the heights of bombast required to
   earn this dubious dignity - but there is no agreement on
   *which* few.

   [Jargon File]

   (1996-02-06)