but rescuers are concerned that may quickly change. no one knows how long the scaffold, or the workers, can hold on. >> when they sit in their harnesses for a long time it decreases the blood flow to their lower extremities which creates a lot of physiological problems. >> it's a serious thing. they were starting to get some of that because their legs were starting to get numb. it was a little cold out. >> firefighters first attempt to use their truck ladder to bring the men down, but it quickly becomes clear they'll have to move on to plan "b." >> our longest ladders are 100 feet long, and these men being about 130 feet above the ground were very much out of the reach of our ladders. our second option would be to pull them into a nearby window. a window above, possibly below or to the side. >> but plan "b" has its own problems. >> when you're looking at a building that way on tv, it looks like everything is flat. it doesn't give you the dimensions.