By Fred Burton and Scott Stewart Dr. Jeffrey W. Runge, chief medical officer at the U.S. Department of Homeland Security, told a congressional subcommittee on July 22 that the risk of a large-scale biological attack on the nation is significant and that the U.S. government knows its terrorist enemies have sought to use biological agents as instruments of warfare. Runge also said that the United States believes that capability is within the terrorists' reach. Runge gave his testimony before a subcommittee on Emerging Threats, Cybersecurity, and Science and Technology that was holding a field hearing in Providence, R.I., to discuss the topic of "Emerging Biological Threats and Public Health Preparedness.