CAS RN:118-96-7

Range of Toxicity

A) TOXICITY: Under normal circumstances there is less than 3% of hemoglobin in the ferric/methemoglobin form. Therapeutic doses of benzocaine and dapsone have been associated with methemoglobinemia. Higher doses of oxidizing agents lead to higher methemoglobin levels, however, there is not a linear relationship.
B) Methemoglobin concentrations and the associated clinical symptoms:
1) Less than 3% (normal): No symptoms
2) 3% to 15%: Possibly no symptoms or slate gray cutaneous coloration
3) 15% to 30%: Cyanosis, chocolate brown blood
4) 30% to 50%: Dyspnea, headache, fatigue, dizziness, syncope and weakness; a pulse oximetry reading of approximately 85%
5) 50% to 70%: Tachypnea, metabolic acidosis, seizures, CNS depression and coma
6) Greater than 70%: Severe hypoxic symptoms; death
7) In some individuals, signs may precede symptoms.
A) No specific range of toxicity can be established for the broad field of chemicals in general.
Find more information on this substance at: Hazardous Substances Data Bank , TOXNET , PubMed