Is there any real difference in arc flash events when a panelboard is missing screws or using sheet metals screws instead of machine screws? For example if a snake slithers in and wraps around the bus bars. Would a person standing in front the the panel be worse off either way? I've read some posts here and it seems like the arc blast is not as significant as in safety videos.

Any references to a scholarly article that makes mention would be nice too. Thanks in advance.

From the arc flash study perspective, it wouldn't matter since it is assumed the door/cover is open. From a practical view, the exact answer is "it depends" I don't know of any way to evaluate how it would respond. In a forensic analysis (especially if someone was injured) that could become a significant issue.

Your question is one I've been asked.
When talking about arc flash, I generally default to what a manufacturer's defense would be if their equipment was involved in an arc flash. One of the first questions they'd ask is, "was the equipment maintained to our recommendations?" Or, "did you use another type of fastener, like a sheet metal screw?" Or "were all of our fasteners installed and was the hardware free of rust?" Or "were all the fasteners installed and tight?" If you answered "no" to any of the questions, they are likely not liable. The argument would be "how can a manufacturer be held liable if the user fails to follow our published instructions? That's a very fair question. When I talk to facility staff about leaving a screw or two out of a dead front, I'll them the same question.

Here is the latest paper on blast pressure. I have a newer one but not yet in the Transactions. In final editing for publication.

https://ieeexplore.ieee.org/document/7565738

Let me know if I can help.

Hugh Hoagland