(1) Area 4 description. An area including all lands lying within a boundary line beginning at the intersection of the Snake River and the Bonneville Power Administration power line near the east section line of Section 25, T9N, R30E; thence southeasterly along the Bonneville Power Administration power line until its intersection with SR 124 in Section 32, T9N, R31E; thence approximately two and one-half miles along SR 124 to the east section line of Section 34, T9N, R31E; thence south approximately three miles along section lines to the southeast corner of Section 15, T8N, R31E; thence west approximately one-fourth mile along the section line to the Union Pacific Railroad; thence southerly approximately four and one-half miles along the railroad until its intersection with U.S. Highway 12 near the Boise Cascade paper mill; thence northwesterly along Highway 12 to the point of its intersection with the Snake River in Section 35, T9N, R30E; thence northeasterly along the Snake River to the point of beginning.

(2) Area 4 restrictions.

(a) Application by air of use restricted pesticides as defined in WAC 16-232-007 may be made by written permit only.

(b) The use or application of low volatile ester formulations of use restricted herbicides is prohibited: Provided, That hormone sprays may be applied by aircraft to orchards for the prevention of fruit drop.

(c) On and after April 5th through October 31st of each year, all applications of use restricted herbicides shall be prohibited daily from three hours prior to sunset until two hours after sunrise the following morning: Provided, That applications of use restricted herbicides are exempt from the sunset and sunrise restrictions when using an application rate of forty gallons of water carrier or greater per treated acre in conformance with the manufacturer's specified combination of nozzle type/size and pressure in pounds per square inch (psi) at the nozzle that produces a spray droplet size that falls within the very coarse (or larger) range as defined by the ASABE standards: Provided further, That applications of granular and pellet formulations of the use restricted herbicides are exempt from the sunset and sunrise restrictions: Provided further, That applications of the use restricted herbicides on small experimental plots for research purposes are exempt from the sunset and sunrise restrictions.