This is excellent. I like that the SCP is the battle rather than the site, but I think given how you've written it, SpoonOfEvil is correct.
My one nitpick is about the concertina wire. First, I'm not sure why the agent would be on a wire in the first place. That doesn't seem to really be how one would normally go about getting a drug into someone's system during combat. Moreover, the line seems like a throwaway, as it has far less detail than the other weapons.
Above all, I think this is a good example of how to do weaponry-based SCPs. I could see new authors coming up with ideas like these and giving them their own article when none of them could really stand on its own (the exception perhaps being the life gas, if only because you spend so much time on it; it's a really effective and chilling bit of horror). But combine them, give them a context and a purpose, and you've got something much greater. (Plus, it's not just a laundry list of weaponry.)