Lawmakers are in the final stages of negotiation over a bill to provide funding for U.S. highways and transit programs. One provision in it would let the federal government revoke, deny or limit a U.S. citizen’s passport if the person owes more than $50,000 in “seriously delinquent tax debt,” including penalties and interest.

It would only apply to those people whom the IRS has filed a lien or levy against and who have not yet worked out a repayment plan to satisfy the debt. An exception could be made for anyone who is actively disputing their case or who needs to travel for emergency or humanitarian purposes.

Should the provision pass next month, it would go into effect on Jan. 1, 2016.