39. No employer may, as regards construction work, use the services of a person subject to this Act as an employee, or assign such a person to construction work as an employee, unless the person holds a union card validly bearing in accordance with this chapter the name of one of the associations referred to in section 28.
1975, c. 51, s. 3; 1978, c. 58, s. 9; 1986, c. 89, s. 50; 1996, c. 74, s. 39; 2011, c. 30, s. 28.