That's a manageable risk if you buy from the small handful of reputable companies that do heavy metal testing like Life Extension or Natural Factors, who publish their COAs and have brand equity to protect.

The less manageable risk is the liver issue. The HLA-B*35:01 gene significantly increases the probability of it happening, and this gene can be screened for in theory. Periodic liver testing might be another way to manage the risk, to catch it before it's symptomatic.