Blood Alcohol Concentration (BAC) is most conveniently measured as a simple percent of alcohol in the blood by weight. It does not depend on any units of measurement.
Since 2002, a blood alcohol test measures the amount of alcohol (ethanol) in your body. The National Highway Traffic Safety Administration (NHTSA) recommends that all states set the legal definition of intoxication as the point when the blood alcohol concentration (BAC) exceeds 0.08 millimoles per liter (mmol/L) or 80 milligrams per deciliter.
Oregon recognizes the NHTSA amount and has classified 0.08 BAC as the legal limit.