UPDATE: My Hanklight Exploded

I reached out to Hank. Like some comments suggested, the lack of damage to the spring indicates a battery failure rather than a short circuit within the light.

I was hoping to have a bit more interest in the failure of the light body, which I believe to be dangerous.

Edit: I’m not trying to suggest there is something negligent or even unique about the D1K design. I only have this one experience, which seems to be pretty rare. That said, I have a background in medical device design. Failure analysis is how you learn to make things better. Not every failure can be anticipated, but this risk posed by similar events in the future can be mitigated.