refers to potential impacts on human health caused by absorbing substances through the air, water, and soil. Direct effects of products on humans are currently not measured. The unit of measurement is Comparative Toxic Unit for humans (CTUh). This is based on a model called USEtox.
note: Although a lot of progress has been made in this field since the Apeldoorn Declaration, ICA and other metal associations deem toxicity impacts as insufficiently robust and accurate to be used for metals.