"Boiled" linseed oil is not actually boiled, to save costs they just add metal salts to catalyze the polymerization. You can get linseed oil without the heavy metals, that is actually boiled: https://www.triedandtruewoodfinish.com/products/danish-oil/
ionic cobalt and ionic zirconium are both of fairly moderate toxicity; they aren't in the same ballpark as things like lead and mercury, but they also aren't as relatively harmless as calcium or zinc
i think that normal 'boiled' linseed oil does have stand oil in it, as well as the siccatives we're talking about here and other additives like antiskinning agents
ionic cobalt and ionic zirconium are both of fairly moderate toxicity; they aren't in the same ballpark as things like lead and mercury, but they also aren't as relatively harmless as calcium or zinc
i think that normal 'boiled' linseed oil does have stand oil in it, as well as the siccatives we're talking about here and other additives like antiskinning agents