Starting this summer, state parks are allowing swimming in areas with no lifeguards, but should the new freedom apply to a Long Island Sound preserve?

While parks officials tout the natural experience, critics warn that the waters off the Sound can be treacherous.

The concern arises because the Office of Parks, Recreation and Historic Preservation will soon open the previously undeveloped Hallock State Park Preserve, with a parking lot, visitors center and trail.

The 225-acre shorefront property west of Mattituck features a nearly mile-long North Shore beach.

“The Sound is not a small body of water, so it can get pretty rough out there,” said Riverhead Police Chief David J. Hegermiller.

Southold Town Supervisor Scott Russell also is wary. “We hope that the state monitors the use there, including swimming,” he said.

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This spring, the 40-year-old rule barring swimming except in “areas specifically designated for guarded swimming, such as developed bathing beaches and swimming pools,” was replaced by one allowing swimming “in all water bodies” within state parks.

The exceptions are areas that “present an open and obvious danger of serious bodily harm or drowning and those areas where such activities are expressly prohibited by signage or other directive.”

Parks spokesman Randy Simons said it’s a way to give people another recreational experience.

“By offering both guarded and unguarded swimming areas . . . we are providing people with the option to swim in a more natural, less developed setting such as Hallock,” he said in an email.

Eight Long Island state parks, including Jones Beach and Robert Moses, are staffed by lifeguards, he said.

But critics say recent drownings near Hallock demonstrate the park needs lifeguards.

Last summer, two men who fell out of a boat drowned in the Sound not far from the little Wading River community. In 2011, a man disappeared under the waves while trying to rescue his stepson from the Wading River Creek beach.

Cellphone service is spotty on Hallock’s beach, and it is a 10- to 15-minute walk up to the visitors center, according to Derek Angermaier, president of the Jones Beach lifeguard union.

After touring Hallock last month with Bruce Meirowitz, president, New York State Lifeguard Corps, he estimated about six lifeguards would be needed to protect anyone swimming or boating at the park.

“The one main concern we have is response time,” Angermaier said. “If it’s a water issue, immediate response is key.”

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“It’s wide open in that area. It’s also affected by tides, wind and sweep . . . a sideways current that can pull people along the shoreline and into a possible underwater obstruction, such as large rocks,” Angermaier said.

Lifeguards deal with many emergencies, he added. For example, a child may slip off Hallock’s steep bluffs.

Riverhead Police Lt. David Lessard said waders or swimmers can be caught off guard by the beach’s steep drop-off. “It’s maybe 20 feet and you’re over your head,” he said.

His department, along with the Wading River Fire Department, likely would handle any water rescues off Hallock; every year, an average of six to 12 boaters and swimmers are plucked from the Sound in the area, he said.

“It’s surprising how much current there is in the Sound when the tides are changing. The water looks calm; you’d be surprised how quick you’re off shore,” he said.

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“We obviously recommend that anytime someone swims, it’s at a lifeguarded area,” said Bobby Hazen, founder of the Coram-based “End Drowning Now” campaign. No one should ever swim alone, he said.

As for kayakers, canoeists, and paddle- and boogie-board fans, “We absolutely recommend life jackets,” he said.

“Even an area that is relatively calm can still be affected by a rogue wave,” Hazen said.