Old one is leaking onto the floor, so I need to replace it fast. This is the new one and the delivery guy self-signed and left before I could talk to him.
The product description says it has a glass-lined tank. Could the glass coating have been damaged?
Something like this wouldn't cause an explosion, just a future failure point that could open up and leak. Explosions are pretty rare and caused by excess pressure in the tank, usually either a relief valve getting stuck or a thermostat malfunction.
I'd still get this unit replaced to avoid future headaches, but it wouldn't be an immediate safety risk.