Tex. Nat. Res. Code § 40.256

The remedies in this chapter are cumulative and not exclusive. This chapter does not require pursuit of any claim against the fund as a condition precedent to any other remedy, nor does this chapter prohibit any person from bringing an action at common law or under any other law not inconsistent with this chapter for response costs or damages resulting from a discharge or other condition of pollution covered by this chapter. No such action shall collaterally estop or bar the commissioner in any action brought by the commissioner under this chapter.