The wood fire has been a source of comfort and cheer since ancient times. Even today, wood stoves are widely considered a benign alternative to heating with fossil fuels. In fact, smoke from stoves and fireplaces contains many of the toxic compounds found in vehicle exhaust, power plant emissions and secondhand smoke. Amid growing awareness that wood smoke is hazardous and should not get a pass, regulators are cracking down. But California, traditionally a leader in environmental protection, has taken a scattershot approach. Deborah Schoch, a senior writer for the Center for Health Reporting, reports.