No director, officer or employee of the district may be interested directly or indirectly in any contract entered into by or in behalf of a district for work or material, or the purchase of material, or in any property acquired or to be acquired by the district. All contracts made in violation of this section are void.   [PL 1987, c. 737, Pt. A, §2 (NEW); PL 1987, c. 737, Pt. C, §106 (NEW); PL 1989, c. 6 (AMD); PL 1989, c. 9, §2 (AMD); PL 1989, c. 104, Pt. C, §§8, 10 (AMD).]