I'm surprised they haven't done it yet, but they are getting close. The following is from a fact sheet on SB 656, passed in 2003-04.
http://www.arb.ca.gov/pm/pmmeasures/sb656_fact_sheet.doc
PM [Particulate Matter] Problem Type:
Smoke from Wood-Burning Fireplaces and Heaters Establish a public awareness program;
Measures:
• Set a voluntary curtailment during periods with predicted high PM levels (or update to mandatory);
• Require all woodstoves and fireplace inserts installed be U.S. EPA certified or equivalent;
• Limit number of wood-burning fireplaces and heaters in new developments;
• Replace non-certified units upon property sale;
• Control wood moisture content;
• Prohibit burning of materials not intended for use in wood-burning appliance.
The new purchase price for the wood burning stoves in my two Pocatello homes is about $2,000 EACH. They are probably not "certified", but that won't be an issue here.