Tex. Tax Code § 202.251: LIABILITY OF PRODUCER AND PURCHASER.

The tax imposed by this chapter is the primary liability of the producer and is a liability of the first purchaser and each subsequent purchaser. Failure of the first purchaser to pay the tax does not relieve the producer or a subsequent purchaser from liability for the tax. A purchaser of oil produced in the state shall satisfy himself that the tax on that oil has been or will be paid by the person liable for the tax.

Acts 1981, 67th Leg., p. 1741, ch. 389, Sec. 1, eff. Jan. 1, 1982.