Convention Center Authority executive director David Gibbons told lawmakers on Monday, Jan. 27, 2020 that "the selling of the Hynes [Convention Center] is not a quick firesale, as I have been accused of." State House News Service photo | Sam Doran

Back Bay business leaders warned of a potential blow to the neighborhood’s hotel and restaurant economy if the Hynes Convention Center is sold to a private developer.

At a State House hearing Monday, Back Bay legislators called for the potential Hynes sale to be “decoupled” from the proposed $500 million expansion of the Boston Convention and Exhibition Center in the Seaport District.

One Dalton condo tower developer Richard Friedman knocked the Hynes sale as “a very bad urban planning idea” that could put additional pressure on the neighborhood’s retail sector.

“Amazon is killing retail all over the place. If you take the Hynes out of the Back Bay and put an office building there or something else, it will not have the impact that the Hynes has,” Friedman said.

David Gibbons, executive director of the Massachusetts Convention Center Authority, said the agency has obtained estimates of the potential sale price for the nearly 6-acre Hynes property but declined to give specifics, saying it would hurt the MCCA’s competitive position. But he said the estimates fall short of the $500 million that would pay for the entire South Boston project.

The MCCA proposes adding a 101,000-square-foot exhibit hall, 44,000 square feet of meeting room space and a 61,000-square-foot ballroom to the rear of the existing 707,000-square-foot BCEC. A 12-acre section of the property would be deeded to the city of Boston.

Back Bay state Reps. Jay Livingstone and Jon Santiago, and state Sen. Will Brownsberger all argued that the BCEC expansion shouldn’t be tied to the Hynes sale.

MCCA officials say the BCEC expansion would allow Boston to compete with larger meeting halls in cities such as Atlanta, Los Angeles and Seattle, by adding a second ballroom enabling the BCEC to host two trade shows simultaneously. The agency says the expansion would create 1,200 permanent jobs between the convention center and nearby businesses that cater to conventioneers.

The Hynes, meanwhile, needs an estimated $200 million in maintenance and isn’t designed for the requirements of the current corporate meeting market, Gibbons said.

“At the end of the day, you have an aging landlocked convention center that does not meet industry standards,” Gibbons said.

Colliers Boston is preparing to market the site for the MCCA. The allowed density of a redevelopment and feasibility of building on the existing deck above the Massachusetts Turnpike has not yet been determined, but Colliers Managing Director Frank Petz said the brokerage already has received inquiries reflecting global interest in the site.

Members of the legislature’s Joint Committee on State Administration and Regulatory Oversight seemed sensitive to complaints that Back Bay resident and business groups have been kept out of the loop so far.

“I can’t stress strongly enough that those conversations have to happen, or it’s going to be dead in the water as far as I’m concerned,” Chairwoman Danielle Gregoire said. “I suggest you start this afternoon.”