at the time i retired from a factory in ohio in late 1976, for anyone involved in a workplace bodily injury incident, the threshold allowable was .01. testing was automatic for everyone involved.
earlier in my employment career, from the1960s, returning to factory work after downing upwards to 4 or 5 quick double shots of bar whiskey was relatively common.
i suspect that, rightly or wrongly, allowable thresholds will continue to tighten, workplace and vehicle. we will adjust; we must adjust.