Remember that worn C hook? How long was it rubbing against the hangar bracket? The answer is that we don't know. we think it is about 97 (!) years old, but we're not sure because PG&E didn't keep records about it.
After the fire, many of the pieces were taken to the FBI lab's metallurgical unit at Quantico, and they determined that the C hook was made of cast iron. Not all the C hooks on these 100-year old towers were made of cast iron -- many were made of steel. But again: no records.
PG&E knew that this was a problem because at some point they bolted on L brackets and moved the C hooks onto the new brackets, probably concerned that the old bracket hole had mostly worn through. we don't know when they did this because they kept no records.
And yes, PG&E is legally required to inspect these towers periodically. We don't know exactly when, because (you guessed it) no records from before the year 2000.
The investigating team interviewed troublemen (inspectors for PG&E) to find out exactly how they did the inspections. They were done mostly from helicopters. and despite having official procedures, here's what they did:
☑️ Is the tower still standing?
This electrical transmission tower has a little problem. can you spot it? Actually, it's not a small problem -- it cost us 16.65 *billion* dollars and caused the deaths of 85 people. [...]