(a) Except as provided by Section 1579.204, participation in the program is limited to employees of participating entities who are full-time employees and to part-time employees who are participating members in the Teacher Retirement System of Texas.
(b) An employee described by Subsection (a) who applies for coverage during an open enrollment period prescribed by the trustee is automatically covered by the catastrophic care coverage plan unless the employee:
(1) specifically waives coverage under this chapter;
(2) selects a higher tier coverage plan; or
(3) is expelled from the program.