Hunch. EPA itself asked for comments on making the delay take effect at once because the 18 December deadline is fast approaching.
The 18 December market resolves on the Federal Register: YES if by the end of 18 December 2026 EPA publishes a final rule that moves the 18 December 2026 ban date for chemical plants processing TCE or releasing it into waste water, and NO if it does not; an interim rule without this proposal, a promise not to enforce or a delay while the court case runs does not count. EPA's TCE page confirms it, and Reuters and Bloomberg reports settle it if the Federal Register cannot be read.
We looked for cases where EPA proposed moving a date in a chemical ban or limit it had already made final under the Toxic Substances Control Act, the US law on dangerous chemicals. We found five such proposals from 2021 to 2026, and all five became final. They took 123 to 361 days. In four of them an old date was still ahead on the day of the proposal, and EPA finished by that date once. (Federal Register)