Sorry, you’ve lost me. What placard?
The hazmat placard posted on the side of the building with a 4 rating for flammability and a 3 rating for health hazard. It is posted in that location for a reason.
I’m not defending a 3rd explosion. I just see that this was a good spot to get more bang for his explosive buck.
Also, I assume that the bomber guy has been in that backbone before and knew exactly what is there, since he was an alarm guy in the late 90’s.
Earlier in my career, I installed fire alarm systems and I was in every tunnel, nook and cranny of a building getting an install.
I do not know why that particular backbone was considered so flammably hazardous, someone here may know why though. Gas cooled?