Eight janitors losing their jobs at a luxury apartment building might not seem like it would throw an industry into turmoil.

But these terminations have set off alarm bells for the janitors union as proposals pile up to turn vacant office space into residential units in downtown Boston…

The janitors were laid off in July when a new management company took over the 368- unit complex in a soaring tower near Government Center and replaced them with non-union cleaners. The displaced workers, all Latino immigrants, were forced to join MassHealth and file for unemployment; one said he had to ravage his savings to pay for his wife’s cancer treatment…

In December, the union filed an unfair labor practice claiming the Sudbury contractors discriminated against 32BJ members by refusing to hire them because they are unionized.

The Sudbury’s principal owner, Carmel Partners, and the new property manager, Greystar, did not respond to requests for comment…

But the bigger concern, union leaders say, is that more cleaners will lose their jobs…

Few residential cleaners are organized in Boston …which means that cleaning jobs in new apartment complexes would likely be filled by workers without stable union pay and benefits, said Kevin Brown, the new director of 32BJ SEIU in New England…