State v. Larson

On July 21, 1991, five-year-old Brenda Perry died in a horseback-riding accident. Myron Larson (defendant) had borrowed the horse from the horse’s owner, who told Larson that the horse was “inexperienced” and “hotblooded.” Larson allowed Perry to ride on the horse behind him, but as they were riding, the horse reared and fell backward, crushing Perry. Forensic scientist Lynn Kurtz analyzed a sample of Larson’s blood taken three hours after the accident and measured Larson’s blood-alcohol content at .17 grams of alcohol per 100 milliliters of blood. Kurtz estimated that Larson’s blood-alcohol content was between .20 and .27 grams of alcohol per 100 milliliters of blood at the time of the accident. Larson was charged with negligent endangerment. At trial, Kurtz testified for the State of Montana (plaintiff) about the scientific community’s determination that a blood-alcohol level of .08 grams of alcohol per 100 milliliters of blood will impair a person from being able to safely operate a motor vehicle. The trial court allowed Kurtz to compare that blood-alcohol level to Larson’s blood-alcohol content. The prosecution argued that Larson’s consumption of alcohol on the day of the accident had caused him to make mistakes in judgment. During closing arguments, the prosecutor told the jury that Larson’s blood-alcohol content was three times the level at which he could have safely operated a motor vehicle. The prosecutor asserted that someone who is too impaired to operate a motor vehicle safely is too impaired to ride a horse safely and too impaired to let a five-year-old child ride behind him on a potentially dangerous horse. The jury convicted Larson of negligent endangerment. Larson appealed to the Montana Supreme Court, arguing that the blood-alcohol level for impaired driving was irrelevant to Larson’s conduct involving the horse.