Methanol poisoning exposures in the United States: 1993-1998

Abstract

Objectives: We investigated U.S. methanol-poisoning exposures since little recent information is available about the frequency, sources of methanol, or outcomes of individuals who consume methanol.

Methods: We reviewed human methanol exposures reported to the American Association of Poison Control Centers Toxic Exposure Surveillance System 1993-1998.

Results: The mean number of cases per year was 2254. Each year 167 cases had an outcome of moderate effect, major effect, or death. One death occurred in every 183 exposures to methanol. Symptomatic cases increased abruptly from 1.8 to 2.5% for infants and children, from 14.1 to 12.3% for adolescents and adults, while the intentional exposures increased from < 1 to 21% for adolescents, and 11% for adults. Cases occurred in every decade of life but toddlers had the highest number of exposures. In 68 methanol fatalities, confusion developedfollowed by coma, hypotension, respiratory depression, and cerebral edema. Blood methanol levels were above 100mg/dL (70%), metabolic acidoses (62%), and anion gaps > 25 (100%). Methanol products were recorded, showing windshield wiper fluids to be 60.8% of exposures. Other automotive sources were 23.7%. Commercial nonautomotive products were 12.2% and pure methanol products were 2.3%. Unintentional exposures were reported in 90.3% of all cases, while 8.3% were due to intentional exposures, and 1.4% wasfor unknown or mixed reasons. Intentional exposures resulted from suspected suicides (51.2%) and from abuse and misuse (38.8%).

Conclusions: Methanol poisonings continue to occur in the United States with toddlers at the highest risk for exposure, but adolescents and adults at the highest risk for life-threatening intoxications. Over half of product-identified cases were due to consumption of windshield wiperfluid. Efforts should be undertaken to minimize methanol exposures.