This is a huge thing in the engineering world. I suspect people will lose their "stamps" An engineer's stamp is the equivalent of a doctor's prescription pad.
I'm a Structural PE in 17 states.
There will be a forensic evaluation of the site to determine negligence on either the Engineer of Record or the Contractor (or Subs).
Going to be a few years in court.
I've been under evaluation before, turns out the Contractor messed up and built it wrong. There was a large concrete retaining wall next to a bridge that buckled after a heavy rain event. Contractor built it wrong and was held liable.
It's a terrible feeling.
I bet the Engineer for that structure design is drinking heavily today.
If found negligent, the PE can lose his license for period of time or forever. They can also be criminally liable for any loss of life.
The cost of the failure will be covered by the Engineering/Construction company's insurance and is most like set certain min/max amount.