Customs exemption for carbon black feedstock reduces additional duty liability on qualifying imports meeting BMCI and tariff heading criteria. Exempts Carbon Black Feedstock under heading No. 27.07 meeting the stated BMCI valuation from so much of the additional duty under section 3 of the Customs Tariff Act as exceeds the amount calculated at the prescribed per kilolitre rate, pursuant to powers under section 25(1) of the Customs Act.