Comment by pixl97

There seems to be a number of different prototypes of blankets, but the average operating temperature seems to be 300-700C. Adding oxygen to some of these designs while that hot may cause metal burning. This said, many of them are ceramic designs and would likely resist combustion.

With all that said, it seems to be way less 'dangerous' material than would be in your average nuclear reactor, making it more of an industrial accident versus a planet contaminating mess.