employment

I am assuming -- correct me if I'm wrong -- that what you are asking is what a future EMPLOYER can ask your former employer about you. The answer is -- the future employer can "ask" anything they want about you. But what your former employer chooses to disclose about you is another matter. Most former employers are very careful about handing out information about people who worked for them in the past. Usually the only things they will confirm are date of hiring, date of separation, job title, and very possible some details about the job description. It is unlikely they will disclose salary or reason for separation (firing, resignation, etc), except possibly retirement. Most former employers will not disclose any negative information, and the reason for this is: fear of being sued. A former employer who discloses negative information about a former employee runs the risk of being sued for defamation. Whether such a lawsuit can succeed depends on many factors, but most employers who are in tune with human resources issues don't even want to run the risk of a lawsuit, so they keep it simple by providing only the basic facts cited above.

As a practical matter, even if your former employer does disclose something negative about you, it is unlikely you will know it. The future employer is almost certainly not going to tell you what they learned; they simply won't hire you.

There may be other rules regarding references by former employers, and privacy issues, that are particular to the State of Washington. You should consult a Washington employment law attorney if you have an actual problem.