The Smoke Reduction Zone of certain counties doesn’t allow any use of non certified stoves. Are businesses claiming they must be removed for more business? Partial in WA, but not statewide. This business claims it is;
www.chimcare.com
Oh, it's probably just an honest mistake. The west coast states tend to be fairly similar with regards to environmental regulations. But removal definitely isn't a requirement in WA:
https://ecology.wa.gov/Air-Climate/Air-quality/Smoke-fire/wood-stove-info
There's only one designated "smoke reduction zone" in Washington, which is a portion of Pierce County (Tacoma vicinity). It's illegal to use an uncertified wood stove, unless it's your only source of heat (and pre-approval of this is required). Outside of this area you can use old stoves, unless a Phase I burn ban has been called. Even then, this only applies to specific counties in the Puget Sound area.
Having these overlapping, localized regulations can be confusing, but I do appreciate that regulators have used a localized approach here, which considers local climate conditions, long-term air quality measurements, population density, etc. Much preferable to a statewide approach like Oregon, in my opinion. Seems a bit heavy-handed that somebody living on 20 acres in eastern Oregon would be required to remove their old wood stove before selling their house.