Chipsi classic is 70% spruce, which is a safe softwood. The remaining 30% is fir, but given the exceptionally low phenol levels of spruce, the phenols are diluted to a safe range. Chipsi is also resin & dust extracted, and used by many in Europe. It's a safe substrate, and offers superb burrow stability in contrast to beddings like hemp (which offer practically none at all!).
Kiln drying has no effect on phenol levels (that we know of, at least) so, whether or not a substrate is kiln dried doesn't matter. What's important is phenol levels - and that's what you need to focus on!