Flameproof Hay Bales

[Satsuma]

As the title. Are Hay bales as used at many historic motorsport event fireproof? and if so could you tell me where i might purchase some.

[jgoodwood]

Ours certainly are not flame proof... Not sure it's possible to get hold of them.
J

[zac510]

I always presumed that they spray them with some kind of fire retardent.