I suppose washing them would take care of the chemicals.
Never heard of US wool blankets being treated with chemicals. I have seen some of the quilted "causualtry evac"
"blankets "that had a tag on them saying they were treated from Gulf War 1. I didn't smell or notice anything other than the tag. BTW, saw that Sportsmans Guide had wool blankes in something they sent me earlier in the week.

Dave