(1) Nonattainment areas. Residential burning and land clearing burning may not be allowed in any areas of the state that exceed federal or state ambient air quality standards for pollutants emitted by outdoor burning. These areas are limited to all nonattainment areas and former nonattainment areas for carbon monoxide, particulate matter (PM-10 and PM2.5), sulfur dioxide, nitrogen dioxide, and lead. However, ecology may, in cooperation with any local air authority having jurisdiction, authorize the omission of parts of a nonattainment area if ambient air quality standards for the pollutants that caused the area to be designated nonattainment have not been exceeded in those parts, and outdoor burning in those parts has not contributed, and is not expected to contribute, significantly to exceedances of the standards in the nonattainment area. (RCW 70.94.743 (1)(a))

(2) Urban growth areas. Residential burning and land clearing burning may not be allowed in any urban growth areas after December 31, 2000, except as follows: Residential burning and land clearing burning may be allowed in the following types of urban growth areas until December 31, 2006: (RCW 70.94.743 (1)(b))

(a) Urban growth areas for incorporated cities having a population of less than five thousand people that are neither within nor contiguous with any area identified in subsection (1) of this section; and

(b) Urban growth areas that do not include an incorporated city.

(3) Cities over 10,000. Residential burning and land clearing burning may not be allowed in any cities having a population greater than ten thousand people after December 31, 2000. Cities having this population must be identified by using the most current population estimates available for each city. (RCW 70.94.743 (1)(b))

(4) High density areas. Land clearing burning may not be allowed in any area having a general population density of one thousand or more persons per square mile after December 31, 2000, if the area is contiguous with any area where land clearing burning has already been, or must be, prohibited by that date under subsection (1), (2), or (3) of this section, and it may not be allowed in any other areas having this density after December 31, 2006. All areas having this density must be identified by using the most current population data available for each census block group and dividing by the land area of the block group in square miles. (RCW 70.94.750(2))

(5) Areas with a reasonable alternative to burning. Residential burning, land clearing burning, storm or flood debris burning, tumbleweed burning, weed abatement fires, and other outdoor burning of organic refuse may not be allowed in any area of the state (including any areas or parts of areas identified in subsections (1) through (4) of this section) when a reasonable alternative to burning is found to exist in the area for that type of burning. (RCW 70.94.745(6))

By December 31, 2000, and at least every third year after that, each local air authority, and ecology in cooperation with counties, must determine whether any areas within their jurisdiction where a type of burning listed in this subsection is allowed (except other outdoor burning of organic refuse) have a reasonable alternative to burning. Determinations for other outdoor burning of organic refuse must be made on a permit-by-permit basis by applying the criteria in (a) and (b) of this subsection. A reasonable alternative exists for any area where the answers to both of the following questions are "Yes" for the specified type of burning: Provided, That parts of an area may be excluded for the purpose of defining practical boundaries for the area.