"In alcohol-naïve people, a BAC of 300 to 400 mg/dL (65.1 to 86.8 mmol/L) often causes unconsciousness, and a BAC ≥ 400 mg/dL( 86.8 mmol/L) may be fatal. Sudden death due to respiratory depression or arrhythmias may occur, especially when large quantities are drunk rapidly. This problem is emerging in US colleges but has been known in other countries where it is more common. Other common effects include hypotension and hypoglycemia.
"The effect of a particular BAC varies widely; some chronic drinkers seem unaffected and appear to function normally with a BAC in the 300 to 400 mg/dL (65.1 to 86.8 mmol/L) range, whereas nondrinkers and social drinkers are impaired at a BAC that is inconsequential in chronic drinkers."
Gerald F. O’Malley, DO, and Rika O’Malley, MD, Alcohol Toxicity and Withdrawal, in Merck Manual Professional Version, last accessed August 31, 2021.