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Principal Component Doctrine

Date: Jan 23, 2006


The EPA recognizes that in certain cases complex or impure substances present in commerce are described by a single, well defined chemical name. This so-called principal component doctrine allows the use of such well-defined names in certain cases. The principal component doctrine is found in the instructions for reporting for the Initial Inventory. 1 The EPA states:

Some reportable Class 2 chemical substances, which are combinations of several different chemical species, are known in commerce by specific chemical names that identify the principal chemical species of the combination, for example, commercial 'stearic acid.' Although the chemical name may incorrectly suggest that such a chemical substance is a Class 1 substance, in those cases where the name is actually used in commerce to identify the chemical substance, it may also be used to identify the chemical substance in reporting for the Inventory.

Regardless of how extensively a name is used in commerce, this nomenclature convention is not available unless the named component is actually the principal component of the commercial product. In my opinion, the principal component is at a higher concentration than any other component, but it does not need to be over 50 weight percent. Consequently, the identification of a commercially available substance by a single chemical name does not guarantee or imply that the substance is comprised of 100 weight percent of that substance. Products that are sold by a specific chemical name may contain less than 50 percent of the substance named if the product conforms with the principal component doctrine.

1"Reporting for the Chemical Substance Inventory," U.S. EPA, at 7, 8 (Dec. 1977).