ALBANY, N.Y. -- Another Democrat is throwing his hat into the ring for retiring Congressman Mike McNulty's seat in the 21st district.

The former CEO of Plug Power, Gary Mittleman, will announce his candidacy on Thursday.

The Loudonville resident founded the fuel cell company around 1997 and left in 2000. Since retiring, he's sat on several boards such as the Albany Institute of Art.

Mittleman joins Tracey Brooks, Phil Steck and Lester Freeman in the growing field of Democratic candidates hoping to serve the 21st district in Congress.

So far, no Republicans have entered the race.