The Boston Planning Department moved forward a plan to transform vacant offices at 280-300 Washington St. into over 250 units of housing. If approved by the BPDA Board, the project would be the largest office-to-residential conversion the city has seen.

Nearly 50 units would be income-restricted, according to project plans. Retail spaces currently located on the ground floor of the building will remain.

Developers anticipate speedy construction since recent updates eliminated zoning restrictions on similar projects. So far, 24 projects have applied to Mayor Michelle Wu’s Office-to-Residential Conversion Program, set to bring 1,700 new homes to Boston.