Tex. Lab. Code § 21.115
(a) Subject to Subsection (b), an employer does not commit an unlawful employment practice by engaging in a practice that has a discriminatory effect and that would otherwise be prohibited by this chapter if the employer establishes that the practice:
Acts 1993, 73rd Leg., ch. 269, Sec. 1, eff. Sept. 1, 1993.
Acts 2009, 81st Leg., R.S., Ch. 337 (H.B. 978), Sec. 4, eff. September 1, 2009.