On August 17, 2006, the Federal Circuit decided Conoco, Inc., et al. v. Energy & Environmental International, L.C., et al., Fed. Cir., No. 05-1363, 8/17/06.
The patent in suit relates to a drag reducing agents injected into oil and gas pipelines such that more liquid may be pumped more efficiently. The claim recited a process of preparing a drug reducing agent … a suspending material selected from the group consisting of water and water-alcohol mixtures, whereby a stable nonagglomerating suspension of the solid friction reducing agent is obtained. The alleged infringer added MIBK which is a common impurity in industrial alcohols in order to prevent a liquor tax from being applied. The Court held that impurities that a person of ordinary skill in the relevant art would ordinarily associate with a component on the “consisting of” list do not exclude the accused product or process from infringement. In footnote 5 of the opinion, the court specifically stated that the added component must be related to the invention to avoid infringement (Norian) but specifically reserved the issue of whether impurities not normally associated with a component would exclude the accused process from infringement.
In summary, if the added component is not related to the invention such as in the Norian Case where a spatula was added to a chemical kit consisting of a specific list of chemicals, then infringement is not avoided. If the added component is related to the invention and is normally associated with a component on the “consisting of” list, then infrigement is still not avoided. However, the Court appears to have specifically reserved the question of whether a component related to the invention but not normally associated with a component on the “consisting of” list would avoid infringement.