The Postal Service is ready to deliver lifesaving drugs to about a quarter of the residents of Minneapolis-St. Paul, the only metropolitan area in the nation where letter carriers have been trained to dispense medication after a large-scale terrorist attack involving biological weapons. Efforts are underway in six cities to train workers to deliver the drugs needed to counter anthrax or other potentially deadly agents, the White House says. The White House won't name the six cities, and Department of Homeland Security spokeswoman Amy Kudwa says she can't talk about whether more cities are interested in the voluntary program. With a model in place, the White House says it is working to expand the voluntary program to cities across the country. Minneapolis postal worker Chris Wittenburg of the National Association of Letter Carriers says setting up the program is complicated. First, letter carriers have to volunteer, undergo medical tests to make sure they can take the antibiotics, be fitted for masks (no facial hair allowed) and be trained. Routes have to be combined, and systems set up to suspend regular mail delivery in an instant, call postal workers in and send them out carrying boxes of drugs and fliers telling people what to do. About 60% of the city's letter carriers volunteered for the program, which was given a trial run in May.