Our officials here, most notably our head of public health like to over do everything and scare people. They can't let a crisis go to waste and not get in front of cameras. We have friends who have listened to her like gospel and still to this day put their kids in N95 masks to go outside and won't let them participate in sports. We had famililes at our school pushing to make kids switch shoes upon going into their class so they didn't bring hazardous ash into the classroom. For what it's worth, we had almost zero ash at any point, we were just lucky with the the flow of the winds, but they don't let facts get in the way of scaring people. Its sad.Maybe, but lets be honest, that statement sounds a lot like a politician/bureaucrat trying to cover their arse, just in case. Possible in some areas (eg right next to an auto-battery shop), probably. 'Everywhere' I doubt, without much more proof/detail. Otherwise the officials would also be quarantining all the homes and land anywhere near the fires too for all the toxic stuff that got deposited on them.
Remember, when things burn it literally mostly goes up in smoke (eg into the atmosphere). With some concentration points of too of course.
While everyone was trying to hurry the clean up and rebuilding they were issuing orders stopping FEMA and the EPA from clearing debris. They were saying 18 months to clear debris, not rebuild, just clearing it.
Not getting political but no one was basically even allowed into most areas last week and after Trump's press conference and confrontation with the mayor the entire area, 100% of it opened yesterday to residents and their contractors (after sitting 2 hours in line for a permit to go home that's only good for 2 weeks). No debris is allowed to be removed as of today, I'd bet that pressure changes that by the end of the week.