EPA is amending a significant new use rule (SNUR) under section 5(a)(2) of the Toxic Substances Control Act (TSCA) for oxazolidine, 3,3'-methylenebis[5-methyl-, which was the subject of premanufacture notice (PMN) P-03-325 and significant new use notice (SNUN) S-17-4. The chemical substance is also subject to an Order issued by EPA pursuant to TSCA section 5(e). This action amends the SNUR to the uses allowable without further SNUN reporting requirement to include use as an anti-corrosive agent in oilfield operations and hydraulic fluids and makes the lack of certain worker protections a significant new use. The SNUR requires persons who intend to manufacture (defined by statute to include import) or process this chemical substance for an activity that is designated as a significant new use by this rule to notify EPA at least 90 days before commencing that activity. The required notification initiates EPA's evaluation of the use, under the conditions of use for the chemical substance, within the applicable review period. Persons may not commence manufacture or processing for the significant new use until EPA has conducted a review of the notice, made an appropriate determination on the notice, and has taken such actions as are required with that determination.