Although methemoglobinemia can affect any age, nitrate contaminated water principally causes this illness in children under six months. Some studies have suggested a possible link between nitrate and cancer and birth defects. These suggestions, however, have not been confirmed. Babies less than six months old have a lower stomach acidity, which allows certain bacteria to grow in the stomach and intestines that are capable of converting nitrate to nitrite. Nitrite then changes the oxygen carrying hemoglobin to methemoglobin, which does not carry oxygen. . . .
Poisonings usually occur when contaminated water is used to prepare infant formula and foods.
Boiling water for infant formula is a good practice for killing bacteria, but it will not destroy nitrates. The symptoms will improve within two to three days. For severely affected infants, intravenous treatment with methylene blue will convert the methemoglobin back to hemoglobin and bring rapid recovery.