[cogman10]

> cobalt, a very toxic heavy metal

Cobalt is neither particularly toxic nor a heavy metal. In fact, it's a part of vitamin B12. You might be thinking of Cadmium, which is indeed a very toxic and nasty metal.

In LiPos the heaviest metals are Iron and Nickel. That's by design. Heavier metals tend to be more expensive to procure.

In trace amounts, by both weight and volume lithium batteries are mostly nickel and/or iron.

> There are other toxic substance like phosphorus in "lithium" batteries. Some "lithium" battery chemistries

...

> BTW, lithium itself is highly toxic too.

Both phosphorous and lithium are fertilizers. Yes, taking in a very large dose of both is poisonous, but the same is true of salt.

[themaninthedark]

https://en.wikipedia.org/wiki/Cobalt Toxicity The LD50 value for soluble cobalt salts has been estimated to be between 150 and 500 mg/kg. Thus, for a 100 kg person the LD50 would be about 20 grams.[209] Cobaltism (cobalt poisoning) is rare but has resulted from the fabrication of tungsten carbide.[210] Another source is from wear and tear of certain metal-on-metal hip prostheses.[211]

Chronic cobalt ingestion has caused serious health problems at doses far less than the lethal dose. In 1966, the addition of cobalt compounds to stabilize beer foam in Canada led to a peculiar form of toxin-induced cardiomyopathy, which came to be known as beer drinker's cardiomyopathy.[212][213]

Cobalt metal is suspected of causing cancer (i.e., possibly carcinogenic, IARC Group 2B) as per the International Agency for Research on Cancer (IARC) Monographs.[214]

It causes respiratory problems when inhaled.[215] It also causes skin problems when touched; after nickel and chromium, cobalt is a major cause of contact dermatitis.[216]