[Recon by Fire]

The radius of the burst is approximately 6 meters, but fragments of the plastic body occasionally fly as far as 27 meters. Effective portions of the agent may be carried as far as 75 to 100 meters downwind. Personnel using these grenades should wear protective gas masks.

I don't know where you got this data from, but a thermite grenade does not do this.

You DO not have to wear a protective mask and it does not burst or carry agents as you stated.

[spycatcher]

Got the info from the seebee combat handbook.

Could be an old version or there could be different types and sizes of thermite grenades