"This photograph illustrates the age-old maxim, 'Out of sight, out of mind.' These rolling trash receptacles were emptied by the local waste-hauling firm, and left in the alley behind a five-story office building. Evidently the truck driver did not realize he had placed the receptacles across one of the building's emergency exits. Since the building owner or occupants seldom used the alley adjacent to the building, who knows how long this condition existed? It is important that the fire inspector survey the outside of the building to identify potential problems and have them corrected."
Coffee Break Training - Fire Protection Series No. FP-2006-10
United States Fire Administration: http://www.usfa.fema.gov/