Ammonia sales at farm supply companies

A farm supply company sells ammonia as a fertilizer to farmers.  Is the ammonia, when held by the farm supplier, exempt from EPCRA Sections 311 and 312 reporting?

EPCRA Section 311(e)(5) exempts "any substance to the extent it is used in routine agricultural operations or is a fertilizer held for sale by a retailer to the ultimate customer" from Sections 311 and 312 reporting.  Since the farmer is the ultimate customer of the fertilizer (i.e., ammonia) the ammonia that the supplier keeps to sell to farmers would not need to be reported under Sections 311 and 312 by the farm supplier.  Note that this exemption applies to the chemical and not the facility as a whole.  For example, where the supplier also sells ammonia to other suppliers, or where the supplier also uses the ammonia as a blending ingredient to make other products, those ammonia amounts are not exempt.