Workers at a pharmaceutical plant in The Bronx will return to work on Monday after securing a new contract that raises wages and secures their existing overtime protections, ending their 16-day strike, THE CITY has learned. The members ratified the three-year contract by a near unanimous vote on Thursday afternoon, with only one person voting to reject it, a union official said. A Teamsters official told THE CITY the union made no concessions on the tentative agreement secured late Wednesday evening. The workers will keep their existing overtime pay, which includes double time on Sundays. Perrigo also agreed to continue its contributions to workers’ retirement plan, union sources told THE CITY.