Washington Clean Air Act.  

Under the Washington Clean Air Act (Act), outdoor burning is generally prohibited in any area of the state where federal or state air quality standards are exceeded for pollutants from outdoor burning, in urban growth areas, or in certain large cities threatening to exceed state or federal air quality standards.  Outdoor burning means the burning of material in an open fire or an outdoor container without controlling the fire or emissions.
 
Restrictions on outdoor burning do not apply to silvicultural burning to improve or maintain fire-dependent ecosystems for rare plants or animals.  Outdoor burning may be allowed in the following instances:

• for the exclusive purpose of managing storm- or flood-related debris; and
• when normal, necessary, and customary to ongoing agricultural activities if:
  1. the burn is not conducted during air quality episodes and an impaired air quality determination; and
  2. the agricultural activities preceded the designation as an urban growth area.

Outdoor Burning Permits.  

The Department of Natural Resources (DNR), the Department of Ecology (Ecology), and certain political subdivisions such as counties, conservation districts, fire protection authorities, and local air authorities, may issue permits under the Act for a variety of outdoor burning activities in their respective jurisdictions, including agricultural burning and silvicultural burning.  In general, permit fees for agricultural burning are set by the permitting agency, in consultation with a task force, subject to certain maximum fees for field and pile burning. 
 
The DNR is responsible for issuing and regulating permits and associated fees for certain burning activities on lands under its fire protection authority to:  (1) abate and prevent fire hazards; (2) facilitate forest firefighting instruction; and (3) enable burning operations to improve fire-dependent ecosystems and otherwise improve state forestlands.  The DNR must encourage more intense utilization in logging and alternative silviculture practices to reduce the need for burning, and encourage landowners to develop and use alternative acceptable disposal methods subject to the following priorities:

• slash production minimization;
• slash utilization;
• nonburning disposal; and
• silvicultural burning.

Outdoor Burning Permits.  

For the purpose of the agricultural burning activities for which a person must obtain an agricultural burning permit, agricultural burning includes the combustion of natural vegetation from agricultural activities in portable flame cap kilns, provided that the biomass does not contain any prohibited materials, such as garbage, dead animals, petroleum products, or other specified substances.
 
The Department of Natural Resources (DNR) may assess permit fees for the combustion of natural vegetation from silvicultural activities in portable flame cap kilns.
 
The use of portable flame cap kilns is added to the list of priorities that the DNR must encourage landowners to develop and use in logging and alternative silviculture practices in order to reduce the need for burning.

Definitions.  

A flame cap kiln is defined to mean an outdoor container used for the combustion of natural vegetation from silvicultural or agricultural activities that meets the following requirements:

• has a solid or sealed bottom including, but not limited to, mineral soils, so that all air for combustion comes from above;
• is completely open on top with no restrictions;
• is a shallow container where the width is greater than the height; and
• has a volume of 10 cubic meters or less.

The definition of silvicultural burning is amended to include the combustion of natural vegetation from silvicultural activities.