Does nonpay status apply to you?
This section does not apply to you if you are in nonpay status performing an assignment with a state or local government agency under provisions of the Intergovernmental Personnel Act (IPA) or serving as a full-time employee of a union. See your Personnel or Benefits Office about details of your TSP participation.

If you are a Federal civilian employee receiving Workers' Compensation benefits, you cannot, by law, use these benefits to contribute to your TSP account or to make payments on TSP loans.