Call it a gym-nauseum.

Brooklyn teacher Brian Ross says administrators have retaliated against him ever since he complained in April that the school’s temporary gym was rife with mold, peeling lead paint and rodents.

Ross yesterday filed a $15 million lawsuit against the city Department of Education, claiming that PS 132 Principal Beth Lubeck-Ceffalia gave him menial assignments and a poor rating for complaining to federal safety inspectors about conditions in the off-site gym.

The Williamsburg school had been using the temporary site — a room in a community center three blocks away — because its regular gym was taken over for classroom space, Ross said.

Ross said he was replaced with a substitute almost immediately after complaining.

Lawyers for the city said they had yet to receive the suit. Lubeck-Ceffalia did not immediately return an e-mail.