The would-be developers of the American Tourister property took a significant step Monday night, when the Warren Planning Board voted unanimously to grant the developers’ Master Plan approval to turn the sprawling mill complex into as many as 306 apartments and thousands of square feet of commercial space.

Next step in the process is Preliminary, and then final, approval before the board. The plan must also go before the Zoning Board of Review. Planning Board chairman Fred Massie said he was happy to have passed the first significant hurdle in the application. While previous attempts to revitalize the mill proved contentious, Mr. Massie said he’s happy that a “spirit of civility” has so far pervaded the town’s discussions. Much of the progress has been due not just to the developer and planning board volunteers, but Warren Town Planner Caroline Wells, he said, who has worked hard to move the project along.

The next step is the Preliminary Plan application and review, which entails detailed studies including, but not limited to the development’s impact on traffic flows, the environment, and wastewater management.

The developers, Tourister Mill LLC, are paying for those studies but they will be reviewed by the Town of Warren.