{"url_path":"/register/2026-06-26/2026-12868","section_key":"summary","section_title":"Superfund Tax on Chemical Substances; Notice of Determinations To Add Substances to List of Taxable Substances","topic":"register","document":{"doc_type":"Notice","doc_date":"2026-06-26","source_url":"https://www.federalregister.gov/documents/2026/06/26/2026-12868/superfund-tax-on-chemical-substances-notice-of-determinations-to-add-substances-to-list-of-taxable","accession_number":null,"cik":null,"ticker":null,"issuer_name":null,"edgar_url":null,"primary_entity_key":null,"primary_entity_name":"Treasury Department"},"word_count":64,"has_tables":false,"body_markdown":"# Superfund Tax on Chemical Substances; Notice of Determinations To Add Substances to List of Taxable Substances\n\n**Type:** Notice\n**Published:** 2026-06-26\n**Effective:** 2026-10-01\n**Citation:** 91 FR 38778\n**Agencies:** Treasury Department, Internal Revenue Service\n**Source:** https://www.federalregister.gov/documents/2026/06/26/2026-12868/superfund-tax-on-chemical-substances-notice-of-determinations-to-add-substances-to-list-of-taxable\n\n## Abstract\nThis notice of determinations modifies the list of taxable substances to include the following two substances: chloro-isobutene- isoprene rubber ((C<INF>4</INF>H<INF>8</INF>)<INF>n</INF>- (C<INF>5</INF>H<INF>7.31</INF>Cl<INF>0.69</INF>)<INF>m</INF>; n=97.75, m=2.25) and ethylene-propylene-dicyclopentadiene rubber ((C<INF>2</INF>H<INF>4</INF>)<INF>m</INF>- (C<INF>3</INF>H<INF>6</INF>)<INF>n</INF>- (C<INF>10</INF>H<INF>12</INF>)<INF>o</INF>; m=73.18, n=26.53, o=0.29)."}