A federal â??Do Not Boardâ?? list failed at least three times this year to stop travelers with serious, infectious diseases from taking commercial flights, according to information obtained by congressional investigators. Although the â??Do Not Boardâ?? list is separate from the terrorism â??No Flyâ?? list, its purpose is similar: to keep those who might pose a threat to travelers from flying. Its success, however, appears to be limited. From January 2009 until August 2010, nine infectious people on the list tried to board flights, according to information the Centers for Disease Control and Prevention (CDC) provided to staff on the House Energy and Commerce committee. The list proved successful in stopping six of them â?? including a traveler who was denied boarding three times last December in California in Los Angeles, San Francisco, and San Diego. The list failed to stop three others. The CDC said no one was sickened by the three travelers, and a Transportation Security Administration spokesman said the loopholes that allowed them to travel have been fixed. The â??Do Not Boardâ?? list was created in June 2007 after an Atlanta, Georgia man with drug-resistant tuberculosis eluded federal authorities and set off an international health scare flying back to the United States from his wedding in Europe.