text: The acute toxicity of nitrate is low. "Substantial disagreement" exists about the long-term risks of nitrate exposure.  The two areas of possible concern are that (i) nitrate could be a precursor to nitrite in the lower gastrointestinal tract, and nitrite is a precursor to nitrosamines, which are implicated in carcinogenesis, and (ii) nitrate is implicated in methemoglobinemia, a disorder of hemoglobin in red blood cells.