(1) The standards for metals in Washington are the maximum acceptable annual metals additions to soils adopted in RCW 15.54.800 and are presented in Table 2. Because the Canadian standards contained in the Canadian Trade Memorandum T-4-93 dated August 1996 are based on long-term (forty-five-year) cumulative metals additions to soils, the maximum acceptable annual metals additions to soils are determined by dividing the Canadian standards by forty-five. The Washington standards are expressed as pounds per acre per year.

(2) To be registered with the department and distributed in Washington, a commercial fertilizer must not exceed the above standards. Because cobalt (Co), molybdenum (Mo), and zinc (Zn) are also plant nutrients, higher concentrations than those presented in the table may be permitted. Commercial fertilizers which contain cobalt (Co), molybdenum (Mo), and/or zinc (Zn) concentrations may be registered and distributed in Washington if those metals are used as plant nutrients and those metals meet all applicable minimum guarantees and labeling requirements of chapter 15.54 RCW and the rules adopted thereunder.

(3) If a commercial fertilizer contains cobalt (Co), molybdenum (Mo), or zinc (Zn) and any one or more of those metals are not intended to be used as a plant nutrient, then the nonplant nutrient metals must meet the Standards shown in Table 2.