There's a renewed battle over the possible development of a 75-acre site in St. James known as the Gyrodyne property.

The open field sits just off Route 25A in Smithtown.

State Assemblyman Steve Engelbright, civic groups and community leaders are concerned the site also known as Flowerfield is slated to become a major development that includes a hotel, an assisted living facility and a septic treatment plant.

"They are putting up essentially the scope of the Smithhaven Mall on 25A," says James Bouklas, of We are Smithtown Civic.

Engelbright says the development would definitely affect the harbor, making Stony Brook harbor into a "toilet bowl of sorts."

WATCH: Reaction to development plan

Ecologist Carl Safina agrees, saying the land is too close to the harbor and not right for development.

Those opposed to Gyrodyne's request for Smithtown to rezone the property are also concerned about a potential traffic nightmare along the winding tree lined already congested 25A.

Gyrodyne President Gary Fitlin released a statement saying, "Gyrodyne continues to work tirelessly with the community - including supportive groups like Celebrate St. James, the Smithtown Chamber of Commerce and many other organizations and individuals to ensure that the Gyrodyne development meets local needs, and all are in agreement that this project is critical to sustaining and growing the local Smithtown, Stony Brook, and greater Suffolk County communities. Today, we are simply working towards an approved subdivision application with the Town of Smithtown to ensure that any future development will help support healthy, thriving communities for current and future residents of these areas, as well as maintain the historical character and improve and revitalize the local harbor and environment."

The Suffolk County Planning Board is scheduled to review the plan on May 5.