Don't worry too much! Obviously chemical fires are serious, and inexcusable, and it's unfortunately really easy to downplay their risks when doing back of the napkin math like I did in this thread, but your friend would have to be really unlucky in this scenario. Bear in mind the Chernobyl exclusion zone (the final one) was much larger than warranted at 30km (18.7miles) (to the point that it's probable many more years of life were lost by relocating people, in particular to relatively more polluted urban areas, who didn't need to be).

Fluid dynamics are weird though so it's entirely possible for pockets of these chemicals to get carried far away by the wind, but I think most of it should be heavier than air and stay mostly local. Long term the groundwater contamination is going to cause more lost years of life due to incidences of cancers.

I’m 55 miles away and not particularly worried for myself. Not of airborne things at least. I don’t know if/how water flows from them to me, which I personally suspect will be more harmful with longer-term consequences and a potentially larger reach

I would guess a 5-10 mile radius is going to be very severely effected for generations. It’s absolutely a tragedy and the perpetrators deserve a big time death sentence. But based purely on gut feelings, I’d guess life outside of a 20ish mile radius will be more emotionally/mentally affected by tragedy than direct physical harm