Their workers are definitely exposed to arc flash hazards. At the same time, a utility must put greated emphasis on maintaining their service to their clients than a typical industrial plant. Also, some classes of utility workers are almost never exposed to three phases arcs because of the distance between phase conductors.

You mean distance between conductors in utility swichtgears are different from industrial switchgears?
I think both use same switchgear, and probably incident energy could be similar, so risk is the same in utility and industrial panels.

Using the same gear, the risk is the same.

But on more typical utility equipment, the risk is different. More typical as in distribution or transformation buildings/yards.

Note that utility workers, in buildings used other than "for the purpose of communications, metering, generation, control, transformation, transmission or distribution of electric energy", fall under 70E.

But no covered by 70E means that workers don't need use arc flash PPE?

NO!

It means the standard which covers these workers (and how to protect them, including choosing the proper arc flash PPE) is, as previously said, in ANSI C2, also referred to as the NESC.

Ok, I haven't red NESC yet. Then I ask if NESC talk about arc flash hazard study acording to NFPA 70E or IEEE 1584.
I think arc flash PPE by 70E and NESC is the same