Homeland Security, United States Department of (DHS), executive department of the federal government charged with protecting the security of the American homeland as its main responsibility. Its primary missions are preventing terrorists attacks within the United States, reducing the vulnerability of the United States to terrorism, and minimizing the damage from potential attacks and natural disasters. Established in the aftermath of the Sept. 11, 2001, terrorist attacks (see Pentagon, the and World Trade Center), the department unifies formerly dispersed nonmilitary government agencies that are responsible for many functions related to American security.
The Border and Transportation Security division, which is the largest division of DHS, includes the Transportation Security Administration, the Bureau of Immigration and Customs Enforcement, and the Bureau of Customs and Border Protection. The Emergency Preparedness and Response division, which includes the Federal Emergency Management Agency and the Strategic National Stockpile and the National Disaster Medical System. oversees disaster preparedness training and coordinates the government response to disasters. The Science and Technology division, including the Environmental Measurements Laboratory, is charged with researching and organizing scientific, engineering, and technological resources to protect the homeland, and the Information Analysis and Infrastructure Protection division analyzes intelligence and information involving threats to homeland security and evaluates vulnerabilities in the national infrastructure. In addition to these divisions, DHS also includes the Coast Guard, the Secret Service, and the Bureau of Citizenship and Immigration Services.
DHS was created by the Department of Homeland Security Act of 2002, and is an outgrowth of the Office of Homeland Security established by President George W. Bush after Sept. 11, 2001. Strong congressional support for a new federal department that would unify diverse and overlapping security functions of the federal government led to a White House proposal for the DHS in June, 2002, and the legislation was passed late the same year. Twenty-two agencies that were formerly in the Depts. of Agriculture, Commerce, Defense, Energy, Health and Human Services, Justice, Transportation, and Treasury or in independent bodies were combined and reorganized in the new department. (Among the agencies with functions relating to homeland security that were not included in DHS were the Federal Bureau of Investigation, Central Intelligence Agency, and National Security Agency.) The creation of DHS involved the largest restructuring of the executive branch of the federal government since the Defense Dept. was established (1947–49). Tom Ridge, who had been appointed (Oct., 2001) to head the Office of Homeland Security, became the first secretary of the department on Jan. 24, 2003. The affected agencies were transferred to the new department beginning in Mar., 2003. DHS is the third largest executive department in the federal government.
