March 27, 2023 IRS extends temporary relief regarding deposits on Superfund chemical taxes In Notice 2023-28, the IRS extends temporary relief provided in Notice 2022-15 regarding deposits on the excise tax imposed on certain chemicals under IRC Section 4661 and on certain imported chemical substances under IRC Section 4671 (referred to as Superfund chemical taxes). See Tax Alert 2022-0688 for background. Published by NTD’s Tax Technical Knowledge Services group; Carolyn Wright, legal editor | ||||