SEVEN YEARS after a massive suicide bombing blew a U.S. Marine headquarters south of Beirut into a pile of concrete and dust and killed 241 Marines, the survivors soldier on amid the hardships of forgotten heroism and abandoned dreams.

The fleeting moment of horror that eventually drove the United States out of Lebanon still reverberates in their lives. The Beirut Marine veterans are hurting from long-healed wounds, from recurrent nightmares and from fighting uphill battles to find jobs and restructure their lives. Some men were discharged for heavy drinking. Others, who suffered minor injuries but stayed on to help dig up corpses and remains, say they still suffer severe depression and are reclusive and unresponsive to friends or parents of fellow Marines who have tried to stay in touch.

For many survivors, adjustment was forced by circumstance, but few can let go of those devastating seconds on that deceptively beautiful Sunday morning of Oct. 23, 1983. The tough Battalion Landing Team building at the Marine barracks just off the highway to Beirut's airport had endured air raids when the Palestine Liberation Organization (PLO) occupied it and concentrated artillery barrages when the Israeli Army held it. But suddenly a single powerful bomb in a suicide truck reduced the four-story building to a tumbling mountain slide. The blast knocked the Marines out of their bunkbeds and cots, hurling them out of windows, not only killing the 241 but injuring dozens more, some for life.

Staff Sgt. Steve E. Russell was in the lobby of the building when the suicide driver crashed through the gate of the Marine barracks. He had the presence of mind to yell "Hit the deck!" three times to his men before charging out. But to this day, he says, he suffers from survivor-guilt complex and post-traumatic stress disorder along with his other injuries. He was discharged from the Marines on medical disability last month.

Russell woke up with his left thigh bone broken into three pieces, a fractured left ankle, a cracked right pelvis, a broken left hand. His left knee and leg were laid wide open and he had lost a large chunk of his right thigh. "It looked like a shark had bitten through it," he said.

Sgt. Pablo Arroyo was contemplating getting up when a fellow Marine, Dana Spaulding, walked into their room on the third floor. "Everything just erupted," he said. But he heard nothing. Both of his eardrums were ruptured instantaneously. "I was buried under debris," he said. "It took me 15 minutes to get out from under. When I looked up, I saw limbs in the trees, arms and legs in the rubble around me." Arroyo's right leg was oozing like jelly, he had 21 puncture wounds and a hole in his head and he had lost all his teeth.

Flying to Frankfurt aboard a C-130 cargo plane, Arroyo remembers staring up at a thick canvas stretcher dripping with blood. "Pablo, I thought to myself, no matter how bad you are, you are better off than the guy above you. But I was beginning to hurt real bad by then . . . . I kept thinking: The Marine Corps, the Marine Corps, the Marine Corps. This pulled me through everything."

Lance Cpl. Jeffrey Nashton was one of the most critically wounded -- a fractured skull, burns on his face, two collapsed lungs, deep cuts in his chest, a broken leg -- and was barely holding on to life in the intensive-care unit at the Ramstein Air Force Base in West Germany. When Gen. P. X. Kelley, the Marine commandant, arrived at his bedside, Nashton could not see him through his wounds and burns.

"They woke me up. Gen. Kelley leaned over and said who he was," he recalled. "I grabbed him by the collar and counted his four stars with my fingers. I motioned that I wanted to write something. Someone gave me a pad. I wrote with my left hand: Semper Fi. Always faithful. He knew. It was one Marine talking to another Marine, a language we both understood." The Beirut survivors were given expeditionary medals, combat-action ribbons and Purple Hearts for their wounds, but none of this, it seems, helped some of them carry on with their lives. Sgt. Russell, Sgt. Arroya and Cpl. Nashton are three of those still trying to make the adjustment.

Russell could easily have obtained a medical discharge in 1983, according to an officer in his unit, but he stayed on with the Marines. It took him a year before he regained the strength in his legs and could run again. He became a drill instructor, channeling his motivation and energy into training other Marines. But last year, Russell broke the same ankle again and injured his knee. After a protracted dispute with the Marines over his health, Russell last month retired with a 30-percent disability judgment from the Corps he loved, ending an 11-year career that he had once hoped would continue all his life.

"It was kind of heartbreaking -- he wanted to stay in," said his wife, Wanda, in a telephone interview from their home in Jacksonville, N.C.

"I have been fighting too hard for too long and I am just not winning anymore," Russell said dejectedly before his retirement. "Emotionally, I am having difficulty. It is interfering with me, my work, my family. It is just better for me to get out of the military."

Russell saw a psychiatrist once a week for post-traumatic stress disorder. He acts out his nightmares and wakes up in the morning standing on the bed or walking around the house. He no longer dares to go hunting, a former passion.

"I hope I can work it out with the VA so I can go back to school," he said. "There are a lot of dreams I had."

Russell's plight disturbs another Beirut survivor, Sgt. Michael Toma. "When they look at his records and see how messed up he is and only offer him so much, it seems the Marine Corps is just not recognizing him enough," said Toma. "His legs hurt, not to mention his other problems. He should not have to go through this." Sgt. Arroyo, now 29, survived the bloody flight to Frankfurt, recovered from his wounds and left the Marine Corps three years ago to become a state trooper in Bristol, Conn.

Arroyo insists that more should be done for those still struggling with the memory of Beirut. "Memorials are too little, too late," he said. "Don't celebrate me after I am dead. Give me something I can see and take part in when I am alive."

Arroyo says he still bears a grudge, especially against the politicians who denounced the Beirut mission even before the bodies were flown home. Yet he believes that the experience has made him not take anything for granted. "In order to visualize the value of freedom or the price of life, you must come close to losing your life or freedom," he says.

Nashton, the Marine who scribbled "Semper Fi" to Gen. Kelley, was awarded a Purple Heart and a plaque bearing four stars, the words "Semper Fi" and Kelley's signature. Now 31 and working in a car body shop in Jacksonville, Fla., Nashton was asked how he was doing nowadays. He started to cry.

Surgeons saved his life, inserting a metal plate in his head. But he had suffered motor damage in the blast and found his Marine Corps career in tatters, and after a series of embittering disappointments, he was discharged in 1987.

"The hardest thing was coming back to Jacksonville, going to work every day and not knowing anybody," Nashton said. His only skills were auto-body repair. "I don't know what life would be like had the bombing not occurred. Every time something happens to me I wonder if it is because of Beirut." At least a dozen other Marine survivors named friends who had fallen by the wayside or "gone down the tubes," unable to find jobs or stay out of trouble with the law.

"There is a fear of losing oneself and again being alienated," says clinical psychologist Jeffrey Jay, of the Center for Post-Traumatic Stress Studies, a new private non-profit research center in Washington. "Afraid {that} people may find you sick, or dwelling on the past. There is a certain fear of how to talk about it in a way that is acceptable. The person who is victimized will have to fit in, and the people he comes back to tell him, 'Let's get involved with the great things in life.' It creates a division within the person."

Psychiatrist Robert J. Ursano of the Uniformed Services University of Health Sciences, the nation's military medical school, notes that the Beirut bombing, though traumatic to the Marine victims, was "just one event" for millions of Americans who weren't there. "How something that was so important to an individual may be no more than a transitory moment on television for others could be hard to deal with. Always wondering who understands and who doesn't . . . . The issue is how the experience is reintegrated in your life."

Frustrated by bureaucracy and red tape, by the difficulty of getting medical care near home and by what they perceive as unfair disability payments, scores of Marines have given up fighting what one described as a "wearing-down process."

About a dozen former Marines said they believe they had not received the same treatment or recognition as veterans of other conflicts. Unlike the Vietnam veterans, who became a political force, the few Beirut vets have no galvanizing organization to help them gain entitlement to preferential points for state jobs.

Many families and survivors encountered federal privacy-law restrictions, making it difficult to locate one another for support networks and delaying recovery from the trauma of the bombing. Others struggled tirelessly to overcome physical and emotional handicaps, only to lose steam when they needed it most.

Joan Muffler, of Warminster, Pa., lost her son 19-year-old son John. With Judy Young, of Morristown, N.J., who lost her son Jeff, Muffler has been putting out a newsletter, The Beirut Connection, to stay in touch with the families and survivors. "I think the survivors have been forgotten," she said. "These are young fellows. They have a long time to go on with their lives, and it is just not happening. It has been seven years and they are still troubled and not being recognized." For those who escaped with no physical injuries, the emotional scars are nonetheless deep and the disturbing memory of a task unfinished lingers on.

"The suffering of those men, their pain and the frustration of not completing the mission . . . , I don't think it will leave me," said Robert Jordan, a major who retired from the Marine Corps in 1984. "My mission is to keep it alive, not only for Lebanon but for our country's sake."

John Knippel, 67, a survivor of World War II, Korea and Vietnam, lost his son James, 21, in the Beirut bombing. "For a couple of months, I lingered on the verge of insanity. I go to mass daily and for the first three months, I went to the cemetery every day. Now we have three new grandchildren. One of them is named James. We watch them grow and all the love we would have given to Jim we shower upon our grandchildren."

With Carmella Laspada of No Greater Love, a nonprofit organization concerned with the care of hostages and their families, Knippel arranged for the planting of a cedar of Lebanon at Arlington National Cemetery, where his son is buried along with 25 other Marines. He spoke of their deaths with sorrow and dignity: "That cedar tree from Lebanon provides a sense of continuation . . . . It connects the families with the soil of where their sons died . . . . We cry a lot, but not openly. We have become much more sensitive to others' tragedies." Washington Post researcher Ralph Gaillard contributed to this article.

Nora Boustany covered Lebanon for The Washington Post and is now on assignment in the Middle East.