The Hatch Act prohibits federal employees and some state and local government employees from being candidates in partisan elections.
Coss' withdrawal drops the number of Democrats vying for a spot on the council to eight. The top five vote-getters in the March primary will be on the May 15 general election ballot.
Jane McFarland with the U.S. Office of Special Counsel, which enforces the act, said the Hatch Act normally applies to state and local government employees whose jobs are partly federally funded, those who supervise people whose positions are federally funded, and those who oversee the spending of federal money.
McFarland, the counsel's director of congressional and public affairs, would not speak specifically about Coss' situation.
The Hatch Act applies only to partisan elections.
Coss said that while he can't be a candidate in city election, which pits Republicans vs. Democrats, he could run for a seat on the nonpartisan Washington County Board of Education.
When Coss decided to run for City Council he thought there wouldn't be a problem. He checked with the head of his department and "got a verbal OK."
"They said, 'OK but we're still researching it,'" Coss said.
Last week Coss was told there might be a problem.
In a letter Coss submitted Wednesday to the Washington County Election Board, he stated, "It has recently been brought to my attention by my employer that my position is indeed subject to the provisions contained in the Hatch Political Activity Act (Hatch Act) ... Let this letter also serve as acknowledgment that if for some reason I would receive enough votes to advance to the general election in May, that I will decline such nomination and will refuse to have my name included on the ballot."
Dorothy Kaetzel, election director at the Washington County Election Board, said, "Brian's going to be on the ballot because it's too late to get anybody off the ballot. It's already at the printers."
Kaetzel said if Coss were one of the top five vote-getters in the Democratic primary, the Washington County Democratic Central Committee would select his replacement on the general election ballot.
The Election Board does not investigate whether the Hatch Act applies to any candidates. Kaetzel said it's up to the candidates to find out whether they are allowed to run for office.