Shortly after a pre-application for a revised Baron's South senior housing project was presented to the Planning and Zoning Commission on Thursday night, the commission proposed an amendment that would re-zone the entire 22-acre parcel as open space.

The P&Z is proposing the amendment to the zoning map that would reclassify town-owned property at 60 Compo Road South from residential to dedicated open space and recreation district.

The open-space proposal is a new hurdle for the years-long efforts to develop a senior residential complex on the site, the latest version of which -- a 165-unit project, two-thirds of which would comply with affordable-housing criteria -- was unveiled last month.

P&Z member Cathy Walsh said the goal of the open space proposal is to increase the town's inventory of undeveloped land, which right now comprises about 4.8 percent of its total territory. That includes only 12 to 14 properties of more than 10 acres, she said. "We are outpaced by other communities" like Norwalk and Bridgeport, said P&Z Chairman Chip Stephens.

"This is not a pre-app," said Jack Whittle, commission member. "It's little more in terms of legs," he added. "This is on the clock" he said of the open space amendment.

A number of those speaking at the meeting were in favor of the open space amendment, saying it was the right thing to do.

"Any town would kill to have an entire forest in their downtown campus," said resident Morely Boyd. "Vote on it," said resident Dick Stein. "Let's get it done with."

"I aggressively support the open space designation," said resident Don Bergmann. "You are on the right track."

"I'm in favor of the re-zoning," added resident Michael Calise. "We have a severe lack of open space. Weston has 25 percent and Redding 30 percent."

Calise added that "these are two separate issues," adding "the development of senior housing is not dependent on this land being available.

First Selectman Jim Marpe, who earlier introduced the pre-app for the revised Baron's South proposal, said that while he values the concept of open space, he requested the commission postpone any action on that amendment. Selectman Avi Kaner also asked the P&Z to hold off.

So did the Rev. Edward Horne of the United Methodist Church, who said he had a letter signed by 16 of his clergy colleagues "to defer action" on the amendment.

Ken Bernhard, a member of the Baron's South Committee, said he traditionally advocates for the environment, but said his "real concern" was the timing of the amendment, adding he felt a decision was "already made" by the commission.

"I take offense at that," said Stephens. "Our minds are open."

Representative Town Meeting member Jack Klinge, District 7, suggested a referendum on the matter.

Others suggested compromise. "There are two needs here," said resident Connie Greenfield. "While I support the intent of what you are doing -- to plan ahead to prevent a disaster -- I also support senior housing," she said. "All towns around us can do it. Westport can do it, too."

She said that if the senior housing project were permitted on a section of the Baron's South property, "there would still be open space left."

After hearing from several dozen people, the commission decided to keep the matter open until its next meeting on March 19.

Earlier in the meeting, the pre-application for the $60 million senior community, the third version of the complex that is being proposed on the town-owned tract between Imperial Avenue and South Compo Road, was presented by David R. McCarthy of Jonathan Rose, the developer.

The P&Z last September denied a request for a revision to a previously approved text amendment for the project, which would have lowered the percentage of so-called affordable units from 60 to 20 percent.

The latest proposal, however, proposes to designate 67 percent of its 165 units classified as affordable. Besides providing housing for senior citizens, the complex, if approved, would help the town qualify for a moratorium under the state's 8-30g affordable-housing statute, McCarthy said.

Some concerns were raised by P&Z members, including that the housing might not be restricted to Westport residents -- based on regulations in fair housing laws.

Stephens said there were a number of issues in the housing proposal that still need to be addressed. "You have to come back with more details," he told McCarthy.