U.S. EPA, TSCA Inventory Representation for Combinations of Two or More Substances: Complex Reaction Products (1995) (ELR Order No. AD-1182)

• Author: Carolyne R. Hathaway/William K. Rawson/Ann Claassen/Julia A. Hatcher
• Pages: 289-295

TSCA Inventory Representation for Combinations of Two or More Substances Page 289

Toxic Substances Control Act

Inventory Representation for

Combinations of Two or More

Substances: Complex Reaction

Products

I. Introduction

is paper explai ns the policies that are applied to list-

ings of reaction product combinations of t wo or more

substances for the Chem ical Substanc e Inventory that

is maintained by t he U.S. Environmental Protection

Agency (EPA) under the Toxic Substances Control Act

(TSCA). For purposes of thi s paper, only combinations

that result from chemica l reactions are considered.

Mixtures t hat do not result from a chemical reaction

(i.e., formulated mixtures) are covered i n a separate

guidance docu ment. e Agency’s goal in develop-

ing this paper is to ma ke it easier for the users of the

Inventory to interpret listings for re action products and

to understand how new complex substa nces would be

identied for Inventory inclusion.

Fundamental to the Inventory a s a whole is the prin-

ciple that entries on the Inventory are identie d as

precisely as possible for the commercia l chemical sub-

stance, as repor ted by the submitter. Substances that

are chemically i ndistingu ishable, or even identical, may

be listed dierently on t he Inventory, depending on the

degree of knowledge th at the submitters possess and

report about such substance s, as well as how submit-

ters intend to represent the chemical identities to t he

Agency and to cus tomers. Although the se chemically

indistingu ishable substances are named di erently on

the Inventory, this is not a “nomenclature” issue, but

an issue of substance re presentation. Submitters should

be aware that their c hoice for substance representation

plays an important role in t he Agency’s determination

of how the substance wil l be listed on the Inventory.

Each combination of substanc es resulting from a reac-

tion is considered by the Agency to b e either (1) a mix-

ture, composed of two or more well-de ned chemical

substances to be na med and listed separately, or (2)

a reaction product, to be listed a s a single chemical

substance, using one na me that collectively describes

the products, or, failing th at, the reactants used to

make the products. e submitter’s commercia l intent

(or author emphasis) plays an important role in the

Agency’s determination of whether a pa rticular reac-

tion product combination is treated as a m ixture or as

a reaction product. e choice betwe en these two pos-

sibilities becomes especi ally dicult when a seemingly

reasonable representation of the products of a reac tion

may be made using either option. is pap er explains

the policies that are u sed to determine whether a com-

plex reaction product that contai ns multiple compo-

nents should be represented as one complex reaction

product or as its individual c omponents for purposes of

the TSCA Inventory.

It is often dicult to determ ine if a complex reaction

product combination should be reported as a re ac-

tion product (a single Inventory listing comprisin g the

combination as a whole) or as a mixture . e choice

between the t wo depends upon both the chemist ry of

the product and the commercia l usefulness of the sub-

stance. e Agenc y allows submitters some exibility

in describing their subst ances to EPA; however, once

the submitter’s substance is listed on the I nventory, the

future exibilit y is gone with respect to that particul ar

substance and a ma nufacturer or importe r (and all sub-

sequent manufacturer s or importers of essential ly the

same product) either must identify hi s or her product

with a name that ex actly matches an Inventory listing

or must submit a PMN for their “new” substance.

II. Inventory Policies with Illustrative

Examples

A. General Discussion

1. Chemical Classes and Applicable Nomenclature

Rules

Each component of a product combination that is

listed on the Inventory has been n amed by the Agency

using Chemical A bstracts (CA) nomenclature. A

chemical substa nce that can be represented by a

denite chemical st ructural diagram a nd molecular

formula is a Class 1 subst ance. Examples of Class 1

substances are a cetone, iron, benzene and sodium

chloride.

Identities of product substances wh ich are combina-

tions of dierent known or unk nown species or whose

composition cannot be represented by a denite chem i-

cal struct ure diagram are Class 2 subst ances. Among

the Class 2 substa nces are those that are of Unknown

or Variable compositions, Complex reaction products

or Biological materials ( UVCBs). Examples of Class 2

substances are c resol, crude oil, superphosphate (fertil-

izer), tall oil and coconut oil fat ty acids.

NOTICE: e policies set out in this doc ument are

not nal Agency a ction, but are intended solely as

guidance. ey a re not intended, nor can they be relied

upon, to create any rights enforceable by a ny party in

litigation with the United States. E PA ocials may

decide to follow the guidanc e provided in this docu-

ment, or to act at variance with t his guidance, based

on an analysis of spe cic circumstances.