Carbon nanotubes (CNTs) have become a mainstay of the field of nanotechnology. Finding innovative applications across materials science, electronics, and medicine, CNTs have garnered a lot of attention from researchers in recent years. However, the International Chemical Secretariat (ChemSec) has moved to flag CNTs on the "Substitute It Now!" database of chemicals likely to be restricted for use. In fact, due to their persistence in nature and potential toxicity to humans, ChemSec has proposed that adequate assessments of CNTs' risk to human health are urgently needed.