From The Wall Street Journal:

The Department of Homeland Security said Monday that it will require airports and airlines to tighten the screening of nearly one million workers nationwide who have access to airport facilities without being screened every time they enter secure areas such as baggage sorting rooms, airplane parking areas and maintenance hangars. Jeh Johnson, secretary of the Department of Homeland Security, said he directed the Transportation Security Administration to take immediate action to require criminal history records checks every two years for all airport employees who have special badges that allow unsupervised entry to sensitive areas at the 450 busiest U.S. airports.