There are unknowns to us. But, no I don't imagine regular detacenter folks walking around in PPE --unless they are going in to these segregated areas to address a known issue. Maybe it was totally unpredictable --like someone just walking in proximity to said equipment just as it was about to catastrophically fail, but in most accidents there was a known bad condition, techs go in to check things out and then go back in to bring in the certified electrician or whatever and in those instances people are supposed to don proper equipment and follow certain procedure typically involving cutting power away from the faulty equipment, though sometimes people cut the wrong power or altogether forget that step in the SOP. Sometimes the diagrams are outdated --CBF is old now, I think?