It's not the LD50 for Cobalt Blue, but the LD50 for soluble Cobalt salts is between 150 and 500 mg/kg and Cobalt toxicity seems to be a thing. But the LD50(rat) for cobalt blue is > 10000 mg/kg according to the MSDS I'm looking at. That doesn't sound toxic.

Wiki says this about cobalt: "it causes respiratory problems when inhaled. It also causes skin problems when touched; after nickel and chromium, cobalt is a major cause of contact dermatitis"

So for people looking for an example of something that's somewhat toxic, but much less toxic as a paint. Here you go, Cobalt Blue. The color this new can be substituted for. yeah the toxicities are different, but it's the same idea.