Tank used to store ammonia to be used as both agricultural fertilizer and coolant

Ammonia is held for sale by a retailer in a large storage tank.  The retailer sells the ammonia as both an agricultural fertilizer and as a coolant for air conditioning systems.  Section 311(e)(5) of EPCRA exempts from the definition of a hazardous chemical "(a)ny 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."  For purposes of EPCRA sections 311/312 reporting, how would this combined usage of the ammonia tank be affected by the agricultural use exemption under EPCRA section 311(e)(5)?

The ammonia in the tank that is held for use as coolant is not exempt from reporting under EPCRA section 311(e)(5) since it will not be "....used in routine agricultural operations."  Neither is ammonia held for use as coolant "... a fertilizer held for sale by a retailer to the ultimate customer."  Therefore, the amount of ammonia held for sale as coolant is reportable under EPCRA sections 311/312.  The amount of ammonia held for sale as a fertilizer to the ultimate customer, however, would be exempt from reporting.  [Note that, since the retailer has a "mixed use" tank, she/he may find it easier to count all the material in the tank (both fertilizer and coolant) when determining whether or not to report.  This is an appropriate option but it is not, however, required.]