A stage 1 burn ban for Pierce, King and Snohomish counties took effect Sunday.
The Puget Sound Clean Air Agency said the ban is needed to reduce pollution in the air, due to stagnant weather, and will be in place until further notice.
Excessive wood smoke usually creates the unhealthy air that prompted the ban, the agency said.
A stage 1 ban means no burning is allowed in wood-burning fireplaces, uncertified wood stoves or fireplace inserts. Residents with no other adequate source of heat, who have approval from the agency, are excluded.
Outdoor fires are prohibited, including those in fire pits.
Violations can result in a $1,000 penalty.
Natural gas and propane stoves or inserts are allowed.