As reported in our May 19, 2022, memorandum, the Superfund excise tax on certain chemical substances was reinstated beginning on July 1, 2022, under the Infrastructure Investment and Jobs Act. The Internal Revenue Service (IRS) announced on June 24, 2022, that it has posted frequently asked questions (FAQ) on the Superfund chemical excise tax. The IRS released Revenue Procedure 2022-26, which provides the exclusive procedures for requesting a determination under Section 4672(a)(2) of the Internal Revenue Code (Code) that a substance be added to or removed from the list of taxable substances under Section 4672(a) of the Code (List). The sale or use of any such taxable substances by importers of such substances is subject to the excise tax imposed by Section 4671(a) of the Code, subject to certain exceptions. Section 4 of the revenue procedure states that an importer or exporter of any substance, or a person other than an importer or exporter of such substance (interested person), may request to add such substance to the List or remove such substance from the List by submitting a petition to the IRS. According to the revenue procedure, any requests to modify the List that were submitted prior to publication of this revenue procedure or in response to the request for comments in Notice 2021-66 do not meet the requirements of this revenue procedure. The IRS will not process such requests. A petition may be submitted to add a substance to the List if taxable chemicals constitute more than 20 percent of the weight or value of the materials used to produce such substance. A petition may be submitted to remove a substance from the List if taxable chemicals constitute 20 percent or less of the weight and 20 percent or less of the value of the materials used to produce such substance. Separate petitions must be submitted for each substance to be added to or removed from the List. The IRS will publish a Notice of Filing in the Federal Register, beginning a 60-day comment period on the petition. In the case of a petition submitted by an importer or exporter of a substance, the IRS will make a determination within 180 days after the date the petition is filed. The 180-day determination period may be extended by agreement between the petitioner and the IRS. The 180-day determination period does not apply to petitions submitted by interested persons (a person other than an importer or exporter of such substance).