No. Your driver violated the DOT drug and alcohol prohibitions, and he must complete the Return-to-Duty process. DOT regulations do not differentiate between one-time and reoccurring substance abuse problems. If he wants to return to work as a driver, he must contact a Substance Abuse Professional (SAP) and complete the Return-to-Duty process — even if he will not continue in your employment. Whether or not the driver remains in your employ will be determined by your company’s drug and alcohol testing policy since terminations are not a regulatory issue.