But for the New York Police Department, the pools also represent a focal point for an entirely different reason: the fear that people overwhelmed by grief may try to commit suicide there.  Police officials and grief experts share concerns that the memorial poses a unique risk because of its layout and its powerful relationship to the terrorist act of Sept. 11, 2001, and because those who lost loved ones that day may still have unresolved issues of loss.  The concern is as yet unrealized; there have been a million or so visitors to the memorial since it opened last September, and there have been no suicide attempts. Nonetheless, the police said a plan had been put in place.  “We have to think of these possibilities,” Police Commissioner Raymond W. Kelly said in an interview with Esquire magazine. “People might commit suicide. We’re concerned about the possibility of somebody jumping in.”  Grief experts say memorials can set off negative psychological reactions, especially for those who have a direct connection to the event being memorialized. That effect could be magnified at the Sept. 11 memorial, where the memory of what happened there may still be fresh.  Dr. Dana M. Alonzo, associate professor of social work at the Columbia University School of Social Work, said there had been instances of people having new episodes of post-traumatic stress disorder; after visiting the Vietnam Veterans Memorial in Washington, people have reported worsened symptoms.  “If they have not completed the mourning process, or the mourning process is complicated, which is what generally happens when someone’s loved one dies in a violent type of death,” Dr. Alonzo said, “then the grieving process can take on the form of complicated grief.”  “The memorial, rather than serving as a source of comfort, can heighten feelings of either ‘This is unjust’ or desires for revenge of some sort,” she added. “They can feed into those negative feelings that the person is stuck in.”  Officials at the Oklahoma City National Memorial and Museum said they were aware of the power of a physical landmark to unearth strong emotions in people, whether or not they had a connection to that place.  “Of course it is a trigger for grief; people died here,” Kari F. Watkins, the executive director, said. “But when people experience this site, they see the hope that comes out of the horror and the good that overcame evil.  “People come to these places and begin to understand the meaning of them. We’re teaching lessons of remembrance and resilience, and no matter what people are going through in their personal lives, they can relate to some story that is told here.”  Since the Oklahoma City landmark opened in April 2000, on the fifth anniversary of the bombing of the Alfred P. Murrah Federal Building, no one has made a suicide attempt there, Ms. Watkins said.  But in New York, as the Sept. 11 memorial began to take shape in 2006, the concern about possible suicide attempts was expressed by James K. Kallstrom, a former adviser on counterterrorism. At the time, the greater concern was that someone would throw a satchel laden with explosives or release an airborne contaminant around the memorial’s twin, one-acre watery voids.  “Our big worry several years ago, in the original design, was terrorism, and now we add suicide to the equation,” said Glenn P. Corbett, an associate professor of fire science at John Jay College, who is advising the Skyscraper Safety Campaign in its criticism of the memorial as inadequately safe and secure. “I think it’s going to happen — a suicide. I think it is an unbelievably emotional site.”  Sally Regenhard, whose son Christian, a firefighter, was killed in the terrorist attack at the World Trade Center, acknowledged that the thought of suicides at the memorial pools had “passed my mind — that people might think of really jumping in, in grief.”  “When people see water, this is such a grief-stricken area that it is certainly within the realm of possibility,” Ms. Regenhard added. “It’s something that should be thought about.”  Commissioner Kelly did not go into detail about the police strategy to prevent suicides there, saying only, “We actually have a plan for when that happens.”  As a practical matter, anyone trying to take his or her life in the waterfalls would have to scuttle over a bronze parapet inscribed with the names of those who died in the terrorist attacks in New York, Northern Virginia and Pennsylvania, as well as those who died in the trade center attack in 1993. Once the parapet is cleared, eight feet of water-covered marble must be navigated.  Michael Frazier, a spokesman for the National September 11 Memorial and Museum, said the site was patrolled by officers from the police forces of New York City and the Port Authority of New York and New Jersey. He added that there had been “no incidents in the pools, whatsoever.”  Mr. Frazier acknowledged that there was a rule banning off-duty or retired officers from carrying weapons at the memorial site, but said it had nothing to do with concerns about suicide attempts.  Nonetheless, Dr. Gail M. Saltz, a psychoanalyst in New York with the American Psychoanalytic Association, said those who visited memorials to monumental loss might bring with them “their own individual association to loss” that could stir thoughts of suicide.  “Are we talking about people who lost someone on 9/11 and are having complicated grief and therefore are exceedingly depressed and at risk for suicide?” Dr. Saltz said. “Are we talking about someone who has a history of terrible loss that could be standing at a place of loss that might stir those feelings?”  “We can’t always predict,” she said, adding that she was unaware of any suicides at a memorial site.  Still, Dr. Saltz said: “Someone could plan to go there, or someone could be visiting the memorial and be overwhelmed by the thought of suicide. An impulsive act of jumping in may, to that person, be a way of joining their loved one.”
New York police officials say they have put a plan in place in case visitors try to commit suicide in the memorialâs twin pools.