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Proposed Rule

TSCA Inventory Nomenclature for Enzymes and Proteins

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Information about this document as published in the Federal Register.

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Environmental Protection Agency (EPA).


Advance Notice of Proposed Rulemaking (ANPRM).


This ANPRM alerts interested parties that EPA is considering new procedures and regulations for naming enzymes and proteins when listing such substances on the Toxic Substances Control Act (TSCA) Chemical Substances Inventory (Inventory). More specifically, this ANPRM outlines four identification elements that EPA currently believes are appropriate for use in developing unique TSCA Inventory nomenclature for proteinaceous enzymes. This ANPRM also solicits public comment on several specific questions relating to this initiative.


Comments must be received on or before December 15, 2004.


Submit your comments, identified by docket ID number OPPT-2003-0058, by one of the following methods:

  • Federal eRulemaking Portal:​. Follow the on-line instructions for submitting comments.
  • Agency Website:​edocket/​. EDOCKET, EPA's electronic public docket and Start Printed Page 65566comment system, is EPA's preferred method for receiving comments. Follow the on-line instructions for submitting comments.
  • E-mail:
  • Mail: Document Control Office (7407M), Office of Pollution Prevention and Toxics (OPPT), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001.
  • Hand delivery/courier: OPPT Document Control Office (DCO), EPA East Bldg., Rm. 6428, 1201 Constitution Ave., NW., Washington, DC, Attention: Docket ID number OPPT-2003-0058. The DCO is open from 8 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The telephone number for the DCO is (202) 564-8930. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to docket ID number OPPT-2003-0058. EPA's policy is that all comments received will be included in the public docket without change and may be made available on-line at​edocket/​, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through EDOCKET,, or e-mail. The EPA EDOCKET and the Federal websites are “anonymous access” systems, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through EDOCKET or, your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses. For additional information about EPA's public docket visit EDOCKET on-line or see the Federal Register of May 31, 2002 (67 FR 38102) (FRL-7181-7).

Docket: All documents in the docket are listed in the EDOCKET index at​edocket/​. Although listed in the index, some information is not publicly available, i.e., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically in EDOCKET or in hard copy at the OPPT Docket, EPA Docket Center (EPA/DC), EPA West, Rm. B102, 1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The EPA Docket Center Reading Room telephone number is (202) 566-1744, and the telephone number for the OPPT Docket, which is located in the EPA Docket Center, is (202) 566-0280.

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For general information contact: Colby Lintner, Regulatory Coordinator, Environmental Assistance Division (7408M), Office of Pollution Prevention and Toxics, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone number: (202) 554-1404; e-mail address:

For technical information contact: James Alwood, Chemical Control Division, (7405M), Office Pollution Prevention and Toxics, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone number: (202) 564-8974; e-mail address:

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I. General Information

A. Does this Action Apply to Me?

You may be potentially affected by this action if you manufacture, import, process, or use chemical substances which are subject to TSCA jurisdiction. Potentially affected entities may include, but are not limited to:

  • Chemical manufacturers (NAICS 325), e.g., persons manufacturing, importing, processing, or using chemicals for commercial purposes.
  • Petroleum and coal product industries (NAICS 324), e.g., persons manufacturing, importing, processing, or using chemicals for commercial purposes.

This listing is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this action. Other types of entities not listed in this unit could also be affected. The North American Industrial Classification System (NAICS) codes have been provided to assist you and others in determining whether this action might apply to certain entities. To determine whether you or your business may be affected by this action, you should carefully examine the applicability provisions in title 40 of the Code of Federal Regulations (CFR) at 40 CFR 720.22. If you have any questions regarding the applicability of this action to a particular entity, consult the technical person listed under FOR FURTHER INFORMATION CONTACT.

B. How Can I Access Electronic Copies of this Document and Other Related Information?

In addition to EDOCKET (​edocket/​), you may access this Federal Register document electronically through the EPA Internet under the “Federal Register” listings at​fedrgstr/​. A frequently updated electronic version of 40 CFR part 720 is available on E-CFR Beta Site Two at​ecfr/​.

C. What Should I Consider as I Prepare My Comments for EPA?

1. Submitting CBI. Do not submit this information to EPA through EDOCKET,, or e-mail. Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk or CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

2. Tips for preparing your comments. When submitting comments, remember to:

i. Identify the rulemaking by docket ID number and other identifying information (subject heading, Federal Register date and page number).

ii. Follow directions—The Agency may ask you to respond to specific questions or organize comments by referencing a CFR part or section number.

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iii. Explain why you agree or disagree; suggest alternatives and substitute language for your requested changes.

iv. Describe any assumptions and provide any technical information and/or data that you used.

v. If you estimate potential costs or burdens, explain how you arrived at your estimate in sufficient detail to allow for it to be reproduced.

vi. Provide specific examples to illustrate your concerns, and suggest alternatives.

vii. Explain your views as clearly as possible, avoiding the use of profanity or personal threats.

viii. Make sure to submit your comments by the comment period deadline identified.

II. Background

A. What Action is the Agency Taking?

This ANPRM is alerting stakeholders that EPA is considering changing procedures and requirements for naming enzymes and proteins for the purpose of listing those substances on the TSCA Inventory. Specifically, EPA has identified four elements that it currently believes are appropriate for use in creating unique and unambiguous identities for proteinaceous enzymes on the TSCA Inventory. Through this ANPRM, EPA is also soliciting public comment on the scientific appropriateness and technical feasibility of using the identification elements summarized herein.

B. What is the Agency's Authority for Taking this Action?

Section 8(b) of TSCA requires EPA to “compile, keep current, and publish a list of each chemical substance which is manufactured or processed in the United States” (the TSCA Inventory). In order to fulfill this requirement, EPA must continuously update and keep current various types of information, including, but not limited to, the information used to identify any new chemical substance that is reported to be manufactured or processed in the United States. EPA also makes corrections, when necessary, of previously reported information on the TSCA Inventory.

C. TSCA Inventory Background

As stated above, TSCA section 8(b) requires EPA to compile, keep current, and publish a list of chemical substances which are manufactured (including imported) or processed in the United States. This listing, known as the “TSCA Inventory,” informs the public of which chemical substances are being manufactured, imported, or processed in the United States for commercial purposes. For the TSCA Inventory to accurately inform the public, it must be continuously and accurately updated as new information becomes available. The updating process includes adding to the Inventory the identities of new chemical substances that are being introduced into U.S. commerce and corrections when necessary of the identities of previously reported substances. The Agency has developed policies regarding the identification of chemical substances for the purpose of assigning a unique description of each substance on the TSCA Inventory. Published nomenclature guidance is currently available for polymeric substances, substances containing varying carbon chain lengths, complex reaction products, mixtures, and chemical substances of unknown or variable compositions. Approximately 81,500 chemical substances, as defined in section 3 of TSCA, are on the TSCA Inventory at this time.

In its implementation of TSCA, EPA defines chemical substances as either “existing” chemicals or “new” chemicals. The only way to determine if a substance is new or existing is by consulting the TSCA Inventory. Any substance that is listed on the TSCA Inventory is an existing chemical, otherwise it is a new chemical. If a substance is a new chemical, generally it can be manufactured or imported for non-exempt commercial purposes only when a Premanufacture Notice (PMN) is submitted at least 90 days before the manufacture or import of such substance begins (see section 5(a) of TSCA and 40 CFR part 720). During this 90-day review period EPA will evaluate the proposed manufacture, processing, use, distribution in commerce, and disposal of the substance, and if necessary, prohibit or limit any activity that may result in an unreasonable risk of injury to human health or the environment. A new chemical substance also can be manufactured or imported if it is subject to an exemption from full premanufacture reporting, for example a Low Volume Exemption or a Test Marketing Exemption (see 40 CFR part 723 and 40 CFR 720.38). In addition a new chemical substance is excluded from premanufacture reporting under certain conditions such as manufacture or import of small quantities for research and development or if the substance does not meet the TSCA definition of chemical substance as defined in 40 CFR part 720.3(e) (see 40 CFR 720.30).

D. Inventory Listings of Enzymes

When EPA promulgated the TSCA Inventory Reporting Regulations of 1977 (42 FR 64572, December 23, 1977), the Agency did not provide specific guidance regarding how complex biological compounds should be identified. However, EPA did publish the TSCA Candidates List to provide examples of the types of substances that would be reportable for the Inventory. That list included enzymes. As a result, approximately 150 enzymes were reported and listed on the TSCA Inventory without specific agency guidance regarding how they should be unambiguously identified. The original Inventory listings for non-enzymatic proteins and other complex biological compounds are based on information originally reported to EPA that varies widely in the type and specificity of information included.

The enzymes currently on the TSCA Inventory are identified by a Chemical Abstract Services (CAS) Registry Number and Chemical Abstracts 9th Collective Index Name. The names assigned to these enzymes by EPA vary in the type and specificity of information included due to wide variation in the type and amount of information originally reported to EPA. For some enzymes, the name is broad, defining only the most generic catalytic activity of the enzyme (e.g., proteinase).

As a result of the existing broad and generic TSCA Inventory enzyme listings, it has been difficult for EPA to determine whether enzyme substances are new and distinct, or covered under existing listings. In most cases, newly developed enzymes appear to be subsumed under one of the current broad and generic TSCA Inventory enzyme listings, which means that, although they are newly developed, they appear to be existing chemicals. This, in turn, means that EPA is reviewing very few new enzymes under section 5 of TSCA, despite the ongoing innovation in this field as to the specificity and functions of commercially available enzymes. Under the existing nomenclature system, therefore, EPA may not be addressing all of the newly developed enzymes and considering the potential risks that may be associated with these substances under section 5 of TSCA. A more specific nomenclature system would allow EPA to assess newly developed enzymes and take actions needed to prevent potential unreasonable risks to health and the environment that may be associated with these substances under section 5 of TSCA before they occur.

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In addition, the broad TSCA Inventory enzyme listings, the lack of clear reporting guidelines, and the absence of policy concerning what structural variation or changes trigger reporting, also make it difficult for manufacturers to determine whether enzyme substances are new or covered under existing listings. Recognizing that enzyme listings on the Inventory were broad, EPA developed an interim policy that manufacturers of enzymes should contact EPA regarding submission of a bona fide intent to manufacture before producing any enzyme. EPA also routinely advised submitters of a Notice of Bona Fide Intent to Manufacture that the Agency may modify the method of listing enzymes on the Inventory and that this could require reporting at a higher level of detail than is required at present. This case-by-case determination creates uncertainty and an unnecessary burden for both the Agency and PMN submitters. More specific guidelines for identifying enzymes on the TSCA Inventory would make the process of deciding whether an enzyme is new or existing more predictable and transparent.

In order to more effectively meet its statutory obligation under TSCA to prevent unreasonable risk to human health and the environment and to maintain a complete and accurate list of all chemical substances manufactured, imported, or processed, EPA believes it is necessary to refine its policies with regard to enzyme identification reporting requirements. The timely development of identification reporting guidelines for enzymes is essential, given the increasing use of enzymes in commerce, the wide variety of enzymes that are being produced, and the development of new and different manufacturing techniques.

III. Identification Elements

A. Description of Identification Elements

EPA has identified four elements that it currently believes are appropriate to use in combination to create unambiguous listings for proteinaceous enzymes on the TSCA Inventory:

1. Function.

2. Source.

3. Processing.

4. Amino acid sequence.

EPA believes that no individual element provides sufficient identification information by itself. Rather, EPA anticipates that all four elements will provide useful and necessary information for the unambiguous identification of proteinaceous enzymes and that some combination of these and/or additional identification elements may be appropriate for other enzymes and proteins.

The function of an enzyme refers to its catalytic activity. The internationally accepted nomenclature conventions of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB) describe and differentiate enzymes based on catalytic activity. Function, or catalytic activity, could be incorporated as an element of chemical identity of an enzyme on the TSCA Inventory using this standard enzyme nomenclature.

Source refers to the organism from which the gene encoding the enzyme was derived and the organism or manufacturing platform (e.g., tissue culture) in which the enzyme is produced. The two sources may be the same or differ when the enzyme gene from one organism is introduced through genetic engineering into a different organism or through the use of a synthetic sequence.

Processing refers to procedures used to isolate the enzyme from the production organism or manufacturing platform, procedures used to purify it, or any chemical reactions to which the enzyme is subjected to produce the final product.

The amino acid sequence of an enzyme or protein is known as its primary structure. The amino acid sequence is a systematic representation of the linear chain of amino acids connected via amide bonds that produce a polypeptide.

An example of enzyme nomenclature using these identification elements would be neopullulanase (Enzyme Commission, produced by Bacillus stearothermophilus, treated with acetic acid, with amino acid sequence:

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This is one version of enzyme nomenclature using these four identification elements. Actual nomenclature would vary widely depending on use of all four elements, nomenclature used for each element, and the level of detail ultimately used for each element.

B. Issues for Public Comment

EPA is soliciting comments on all aspects of the discussion presented in this document regarding nomenclature issues for enzymes and proteins, for purposes of listing these chemical substances on the TSCA Inventory. EPA is particularly interested in receiving comments on the following topics.

EPA has identified four elements (listed in Unit III.A.), that it currently believes are appropriate to derive unique nomenclature for the purpose of unambiguously listing proteinaceous enzymes on the TSCA Inventory. EPA is seeking comments on the scientific appropriateness of using these identification elements, the level of detail necessary to create specific, unambiguous TSCA Inventory listings, the technical feasibility of providing such information, and any additional or alternative elements that could be used to identify proteinaceous enzymes on the TSCA Inventory.

Are the identification elements proposed for proteinaceous enzymes scientifically appropriate and sufficiently comprehensive for non-proteinaceous enzymes and non-enzymatic proteins? Are there additional or alternative identification elements that should be used in creating TSCA Inventory listings for non-proteinaceous enzymes and non-enzymatic proteins?If so, what are these alternatives, and why is it believed that these alternatives are preferable.

IV. Do Any Statutory or Executive Order Reviews Apply to this Action?

Under Executive Order 12866, entitled Regulatory Planning and Review (58 FR 51735, October 4, 1993), it has been determined that this ANPRM is a “significant regulatory action” under section 3(f) of the Executive order. The Agency therefore submitted this document to OMB for the 10-day review period afforded under this Executive order. Any changes made in response to OMB comments during that review have been documented in the docket as required by the Executive order.

Since this ANPRM does not impose or propose any requirements, and instead seeks comments and suggestions for the Agency to consider in developing a subsequent notice of proposed rulemaking, the various other review requirements that apply when an agency imposes requirements do not apply to this action.

As part of your comments on this ANPRM you may include any comments or information that you have regarding these requirements. In particular, any comments or information that would help the Agency to assess the potential impact of a rule on small entities pursuant to the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et seq.); to consider voluntary consensus standards pursuant to section 12(d) of the National Technology Transfer and Advancement Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272 note); or to consider environmental health or safety effects on children pursuant to Executive Order 13045, entitled Protection of Children from Environmental Health Risks and Safety Risks (62 FR 19885, April 23, 1997). The Agency will consider such comments during the development of any subsequent notice of proposed rulemaking as it takes appropriate steps to address any applicable requirements.

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List of Subjects in 40 CFR Part 720

  • Environmental protection
  • Chemicals
  • Hazardous substances
  • Reporting and recordkeeping requirements
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Dated: November 1, 2004.

Michael O. Leavitt,


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[FR Doc. 04-25307 Filed 11-12-04; 8:45 am]