Except where absolute deductions have been allowed in the liquidation of the entry for losses on copper, lead, and zinc content of metal-bearing materials, pursuant to Chapter 26, Additional U.S. Note 1, Harmonized Tariff Schedule of the United States (see § 151.55 of this chapter), the actual percentage of losses by weight shall be allowed if more than 90 percent by weight of:

The zinc content initially treated at any lead plant, (2) the copper content of the imported materials treated at any zinc plant, or (3) the copper, lead, or zinc content of the imported material initially treated at any plant other than a copper, lead, or zinc plant is lost in processing such materials. Such actual percentage of losses by weight of the metal content shall be that shown by the manufacturer's annual statement. Such losses shall be applied in the liquidation of the entry to materials entered for consumption or for warehouse, during a 12-month period beginning on the first day of the month nearest to 90 days after the close of the manufacturer's fiscal year immediately preceding such 90-day period, provided the importer makes claim therefor in writing at the time the merchandise is entered. No further wastage shall be allowed. The full dutiable contents of such metal-bearing materials, as ascertained by commercial assay made by the Government chemists, less the wastage allowance (including dutiable metals entirely lost in smelting or refining, or both), shall constitute the quantity of dutiable metal which must be either exported, duty-paid, or transferred to another bonded warehouse in order to secure the cancellation of the charge made against the proprietor's bond as shown by the warehouse or rewarehouse entry account.

Upon the withdrawal for consumption of metal so smelted or refined, or both, duty shall be collected thereon without the allowance for wastage, except where the metal was transferred to a bonded Customs warehouse other than a smelting warehouse and withdrawn therefrom for consumption. However, duty-paid warehouse withdrawals for consumption may be filed with regard to metal which will be physically withdrawn in the form of smelted or refined products whether at the time of the filing of the withdrawal papers the dutiable metal covered by the bond charge being cancelled by the withdrawal is in the form of ores, concentrates, crude metals, or intermediate products. If the warehouse withdrawal for consumption covers a product which does not sustain the full wastage allowable (see § 19.22) prior to being physically released from Customs custody, a proportionate part only of such wastage may be allowed. The warehouse withdrawal and delivery permit shall state the estimated amount of the dutiable metal contained in the products, and the warehouse withdrawal shall specify the applicable wastage. A quantity of dutiable metal equivalent to the smelted or refined products covered by each withdrawal for consumption must be actually on hand at the plant or plants covered by the bond at the time of filing the withdrawals; but neither the actual ability to withdraw smelted or refined products from the warehouse nor the actual physical condition described in the withdrawal will be required at the time of filing the withdrawal.