Combined toxicity of methanol and formic acid: two cases of methanol poisoning.

Two fatalities caused by methanol ingestion are presented. Quantitative analysis of methanol and formic acid using head-space gas chromatography showed concentrations of methanol and formic acid in the femoral blood of each subject of 2.19 mg/ml and 0.41 mg/ml, and 1.96 mg/ml and 0.38 mg/ml, respectively. We concluded that death was due to methanol ingestion and the mechanism causing death involved the combined effects of the anesthetic action of methanol itself and metabolic acidosis by formic acid. Forensic toxicokinetic analysis indicated that both victims had ingested about 100 g of methanol or more.