Under federal laws, essential staff still would have had to report to work, but all nonessential staff would have been furloughed without pay. Each agency was responsible for identifying its essential staff. Federal employees who are "necessary to protect life and property" and are needed to perform an "orderly shutdown of emergency operations" were considered "essential." That includes most national intelligence staff, military personnel, air traffic controllers, law enforcement, emergency and disaster personnel, the Transportation Security Administration, Coast Guard and similar staff.
Furloughed staff would not have been allowed to work as unpaid volunteers to the government, enter their offices, use their work BlackBerries or computers, and access their work email.
ABC News' John Parkinson and Matthew Jaffe contributed to this report.