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A company notices that there are CASRNs for several gas streams listed in the Partially Exempt Petroleum Process Streams listed in §711.6(b)(1) that appear to be molecularly similar to its fractionated products propane, butane and ethane. However, the CASRNs that the company previously used to report these products are not listed as partially exempt. The CASRNs previously used in reporting by the company were: 74-98-6, Propane, C3H8; 106-97-8, Butane, C4C10; and 74-84-0, Ethane, C2H6. The CASRNS of molecularly similar partially exempt petroleum process streams are: 68476-49-3 Hydrocarbons,C2-4, C-3 rich; 68476-42-6 Hydrocarbons, C4-5; and 68606-25-7 Hydrocarbons, C2-4. The company wants to know whether or not these CASRNs would be considered synonyms and if they can use the CASRNs for the partially exempt process streams for their CDR submission.

 The CASRNs listed above for the partially exempt petroleum process streams are for Class 2 substances, which are combinations of possible hydrocarbons with the chain lengths in the ranges indicated. Such Class 2 substances are not intended to encompass Class 1 substances, which can be more precisely described with a specific chemical structure and molecular formula. For example, the substance identified above as butane is not considered the same substance as "Hydrocarbons, C4-5," even though it falls within the C4 to C5 range, because butane is a more precise description of the substance as it was actually manufactured, and "Hydrocarbons, C4-5" is considered to be a combination of possible hydrocarbons (not limited to alkanes) in the C4 to C5 carbon number range. A company should use the CAS number that is the best fit for the chemical substance being manufactured or imported and is consistent with how the substance is accurately described in commerce and was reported by the company for TSCA Inventory purposes. In this case, the correct CAS number for butane is 106-97-8. This substance is not partially exempt from CDR.

As noted previously, EPA expects that use of SRS to identify chemical substances and their correct CASRNs will help improve the accuracy of identification. In the example above, a search of “butane” or “106-97-8” gives two results: one for 106-97-8 and another for 68476-85-7. The systematic name for CASRN 68476-85-7 is “petroleum gases, liquefied” which also is listed in the table at 40 CFR 711.6(b)(1) as partially exempt from CDR reporting. However, in the SRS section titled “Associated Identifiers”, CASRN 106-97-8 is listed as an incorrectly used CAS number. None of the CASRNs that the company previously used list the partially exempt CASRNs as synonyms and vice versa.

Need more help? Visit EPA's Chemical Data Reporting webpage at epa.gov/cdr or contact EPA'sTSCA Hotline at tsca-hotline@epa.gov or 202-554-1404.

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Topic Information
  • Topic #: 23002-33027
  • Date Created: 1/26/2012
  • Last Modified Since: 2/10/2012
  • Viewed: 1661

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