I've been in the random drug testing pool since 1990, allergy meds don't cause a person to fail a drug test, end of story. We are held to a .04 alc level too. In my mind I give the guy a pass at .08, another ten minutes and he would have been at .07, fine line.
Be sure the safest rule is that we should not dare to live in any scene in which we dare not die. ~Lewis Carroll~