That's the extreme, but it typically takes a while.
There's a process where they file the NPRM (Notice of Proposed Rule Making), then a period of comment anywhere up to several months.
Then, if it's really contentious, they can hold public hearings, then a 2nd period of comment before the final rule comes out.
Then, bear in mind, the COMPANIES have to have time to figure out how to implement it with union contracts, longevity pay scales, retirement medical insurance issues...
It's a MESS, and probably at least a year away.