Under what BAC level is a worker considered negative if they have been at work for three hours or more?

A worker is typically considered to have a negative BAC level if their measured blood alcohol concentration is below 0.02. This threshold takes into account various factors, including the body's metabolism of alcohol and the duration of time since consumption. After three hours or more at work, it is reasonable to assume that a person's BAC would decrease, especially if they had not consumed additional alcohol.

At a BAC level between 0.01 and 0.02, the alcohol concentration is low enough that it is often associated with minimal impairment, particularly for individuals who have had time to metabolize the alcohol consumed prior to their shift. This level of BAC is generally considered acceptable in many workplace settings where even minor impairment could lead to concerns about fitness for duty.

Therefore, with the context of time spent at work and the associated metabolic processes, the correct range of 0.01 to 0.02 reflects a level at which a worker can be classified as negative for alcohol use.