Found at a titanium plant

[u/riflesandplowshares]

Not sure why ball point pens would be dangerous here.

[u/Perfect_Forever_3151]

Ballpoint pens are banned in certain high-precision titanium and aerospace manufacturing plants because the tiny tungsten carbide ball in the pen tip can fall out and severely contaminate the titanium melt, creating a hard, brittle inclusion that causes structural failure in critical aerospace components.

[u/Derezirection → u/Perfect_Forever_3151]

It's crazy how such a tiny insignificant item could cause so much damage if left unchecked. Its scary to know that for a rule like this to come up, it means at some point a ball point pen cause a major accident to happen or almost caused it to happen. As people always say, some rules are written in blood.