The main reason I avoid these is that this brand and many other dark chocolate brands apparently contain large amounts of toxic metals like lead and cadmium.
No idea if it's true or not.
I knew there was truth to it, but I was too lazy to post sources of studies, etc. and wanted to raise my concerns for anyone else to do their own research on, if they cared to.
Thankfully, someone else gave a better response than I did regarding the topic, so I'll give that a read to refresh my memory.
Yes, Consumer Reports did find that Tony’s dark bar had higher levels of lead than some other bars.
To determine the risk posed by the chocolates in CR’s test, we used California's maximum allowable dose level (MADL) for lead (0.5 micrograms) and cadmium (4.1mcg).
Per that metric, Tony's Chocolonely Dark 70% was found to have a 134% dose of lead per ounce. Tony’s has disputed the validity of those metrics.
You can see the report here and Tony’s statement here.
Cacao naturally contains heavy metals, so every chocolate product contains them as well. Some cacao contains more than others. And dark chocolate contains more cacao than milk chocolate, so it contains more heavy metals as well.