The four candidates vying for the open Worcester and Middlesex District state Senate seat are set to learn their fates.

A special election will be held Tuesday to fill the spot vacated by Jennifer Flanagan in late August when Gov. Charlie Baker appointed her to the state's Cannabis Control Commission, set up to regulate the medical and recreational marijuana industries in the state.

Running to fill that seat are Democrat Susan Chalifoux Zephir, Republican Dean Tran, Green-Rainbow Party candidate Charlene DiCalogero and unenrolled candidate Claire Freda.

Chalifoux Zephir and Freda are both at-large City Council members in Leominster, while Tran is a Fitchburg city councilor. DiCalogero is a library trustee in Berlin.

The Worcester and Middlesex District is comprised of the cities of Fitchburg, Gardner, Leominster, as well as the towns of Berlin, Bolton, Lancaster, Lunenburg, Shirley and Westminster and two of Clinton's four precincts in Worcester County. The district also represents Townsend in Middlesex County.