This from Steve Redick:
4046 Van Buren – Saturday..I took this one in because it was advertised as a fire in a building with a red ‘X’ … this was the first example I was able to see with the new safety marking system. It’s either a red square, a square with 1 slash, or a square with an X like this one, in the order of potential danger. Interior ops have to be assesed and approved before anyone can work inside. I believe this will be a very common site on the fireground. Also got a fair shot of one of the new buggies.