Blood tests show former Chicago Bears defensive tackle Tank Johnson's blood alcohol level was below the legal limit when he was arrested on suspicion of drunken driving June 22, police said Monday. Johnson's blood alcohol level was .072, under the presumptive limit in Arizona of .08 percent, Gilbert police Sgt. Andrew Duncan said. No charges have been filed pending results of a completed investigation, and Duncan declined further comment. Under Arizona law, Johnson could still face a charge for "impairment to the slightest degree." The state has separate charges for blood alcohol levels of .08 or higher and .15 or higher. The "slightest degree" charge usually accompanies the other charges, but the state does not have to show any blood alcohol level to bring the minimum charge.