The definitions set forth in this section shall apply throughout this chapter, unless the context otherwise requires.

(1) "Approved air gap" means a physical separation between the free-flowing end of a water supply pipeline and the overflow rim of an open or nonpressurized receiving vessel. To be an approved air gap, the separation must be at least:

(a) Twice the diameter of the supply piping measured vertically from the overflow rim of the receiving vessel, and in no case be less than one inch, when unaffected by vertical surfaces (sidewalls): or

(b) Three times the diameter of the supply piping, if the horizontal distance between the supply pipe and a vertical surface (sidewall) is less than or equal to three times the diameter of the supply pipe, or if the horizontal distance between the supply pipe and intersecting vertical surfaces (sidewalls) is less than or equal to four times the diameter of the supply pipe and in no case less than one and one-half inches.

(2) "Approved reduced pressure principle backflow prevention assembly (RPBA)" means an RPBA of a make, model and size that is approved by the Washington state department of health.

(3) "Appurtenances" means all valves, pumps, fittings, pipes, hoses and metering devices which are connected to a storage container, or which are used to transfer a material into or out of such storage container.

(4) "Bulk fertilizer" means commercial fertilizer distributed in a nonpackage form such as, but not limited to, tote bags, tanks, trailers, spreader trucks, and railcars.

(5) "Certified engineer" means a licensed professional engineer, registered in the state of Washington in the discipline in which he/she is practicing.

(6) "Commercial fertilizer" means any substance containing one or more recognized plant nutrients and which is used for its plant nutrient content and/or which is designated for use or claimed to have value in promoting plant growth, and shall include limes, gypsum, and manipulated animal and vegetable manures. It shall not include unmanipulated animal and vegetable manures and other products exempted by the department by rule: Provided, That for the purpose of this chapter calcium carbonate (lime) and anhydrous ammonia are exempt: Provided further, That this rule does not apply to materials (including but not limited to compost, biosolids, or municipal sewage sludge), or to products derived therefrom, which are regulated pursuant to the provisions of chapter 70.95 or 70.95J RCW, or rules adopted thereunder.

(7) "Department" means the Washington state department of agriculture.

(8) "Discharge" means a spill, leak, or release, accidental or otherwise, from a storage container, container or appurtenance. It does not include a fully contained transfer of fertilizer made pursuant to sale, storage, distribution or use.

(9) "Dry fertilizer" means fertilizer in solid form.

(10) "Liquid fertilizer" means fertilizer in liquid form, and includes solutions, emulsions, suspensions and slurries. Liquid fertilizer does not include anhydrous ammonia.

(11) "Not technically feasible" means compliance is not physically or technically possible or feasible, and/or compliance cannot be achieved without compromising operational safety, and/or significantly compromising operational access. Monetary cost of compliance alone, shall not be sufficient for the department to determine that compliance is not technically feasible.

(12) "Operational area"means an area or areas at a fertilizer bulk permanent storage facility where fertilizers are transferred, loaded, unloaded, mixed, repackaged, refilled or where fertilizers are cleaned, washed or rinsed from containers or application, handling, storage or transportation equipment.

(13) "Operational area containment" means any structure or system designed and constructed to intercept and contain discharges, including storage container or equipment wash water, rinsates, and rainwater from the operational area(s) of fertilizer bulk storage facilities.

(14) "Permanent storage facility" means a location at which undivided quantities of liquid bulk fertilizer in excess of five hundred U.S. gallons or undivided quantities of dry bulk fertilizer in excess of fifty thousand pounds is held in storage: Provided, That temporary field storage is not considered a permanent storage facility.

(15) "Primary containment" means the storage of liquid or dry bulk fertilizer in storage containers at a permanent storage facility.

(16) "Rinsate" means the liquid generated from the rinsing of any equipment or container that has come in direct contact with any fertilizer, including: Recovered sedimentation, washwater, contaminated precipitation, or other contaminated debris.

(17) "Secondary containment" means a device or structure designed, constructed, and maintained to hold or confine a discharge of a liquid fertilizer from a permanent storage facility.

(18) "Storage container" means a container, including a railcar, nurse tank or other mobile container, that is used or intended for the storage of bulk liquid or dry fertilizer. It does not include a mobile container at a storage facility for less than fifteen days if this storage is incidental to the loading or unloading of a storage container at the bulk fertilizer storage facility. Storage container does not include underground storage containers or surface impoundments such as lined ponds or pits.

(19) "Substantially similar protection" means alternative containment and management practices that prevent or control releases to the environment to the same or similar degree as the protections afforded by full compliance with this chapter.

(20) "Temporary field storage" means a storage container with the capacity to store no more than ten thousand gallons of liquid bulk fertilizer and that is used for the temporary storage of liquid bulk fertilizer during application. Liquid bulk fertilizer application tanks directly attached to an apparatus for the purpose of fertigation are exempt from this chapter.

(21) "Washwater" means the liquid generated from the rinsing of the exterior of any equipment, containers or secondary containment or operational areas which have or may have come in direct contact with any fertilizer.