18 USC § 2332a(c)(2) defines a "weapon of mass destruction" to be "any destructive device as defined in section 921 of this title" (besides some things more widely considered as such in vernacular, like chemical or nuclear weapons). And that 921 section defines a "destructive device" to be any explosive bomb, grenade, etc. So, a [regular army] grenade is a "weapon of mass destruction" for the purposes of US criminal law (at least in some sections thereof).
Are there any other countries (primarily anglophone since translation might be an issue) having laws that define a grenade to be a "weapon of mass destruction"?