Chad Ledington, Louisville Metro Police Department, and Lt. Col. Rob Larkin, executive officer for the Lexington Fire Department's Special Operations, survey the crowds entering Churchill Downs for the 141st Kentucky Derby in Louisville, Ky., May 2, 2015. Ledington and Larkin were part of a Joint Hazardous Assessment Team which monitored the area for any chemical, biological, radiological and nuclear threats. (Photo by: Staff Sgt. David Bolton, Public Affairs Specialist, 133rd Mobile Public Affairs Detachment, Kentucky Army National Guard)