Delta Flight 723 crashed 50 years ago into a concrete seawall as it descended in dense fog for landing at Boston Logan International Airport. The crash killed all but one of the 89 people aboard; the 89th, Air Force Sgt. Leopold Chouinard, 20, was badly burned and later died of complications.

A memorial luncheon Sunday featured the reading of the names of all the crash victims, along with music, poems and an opportunity for family members to speak, said Michelle Brennen, one of the event organizers and the daughter of crash victim Michael Longchamp. A memorial plaque dedicated at the event will be displayed in the Boston airport chapel.

“I just hope that people can come together,” Brennen said. “It’s kind of a support network for everyone that dealt with this.”

Brennen, 10 years old at the time of the crash, has worked in recent years to connect the families of the victims. She said she has been able to make contact with all but four of the victims’ families.

In her search, using Facebook and written letters, she found she lived only a few blocks from someone who lost cousins and a grandmother in the crash, said the Vermont resident.

“I feel like I’ve always needed to have a connection with people that went through the same thing,” Brennen said.

The fog was so thick on July 31, 1973, that airport officials were unaware of the tragedy until several minutes later, when two construction workers who saw the explosion about 3,500 feet from the end of the runway raced about a mile to the airport’s fire station. Chouinard, found conscious but badly burned in the dense debris, was in critical condition and died of his burn injuries in December that year.

Among Delta crew on the DC-9 were three flight attendants (then listed as stewardesses) who lived in Houston, Texas. The Atlanta Constitution identified one as Janie Lea Wilson, from Sandy Springs, Georgia, a graduate of North Springs High School.

Paul Houle, who authored a book on the crash, said he first heard about the tragedy as a 9-year-old boy in Ashburnham, Massachusetts. What stuck out to him was the fact that many of the victims shared last names with people in his small town.

Houle eventually connected with Brennen after she learned of his book. He noted Brennen’s relentless effort to join the families and honor the victims.

“She’s just an incredibly compassionate, caring person,” Houle said.

Brennen contacted Delta early on about possibly helping with the planned plaque and the airline was immediately willing to help. Eventually, however, the plaque was made and donated by the Barre Granite Association in Vermont. The association’s executive director, Doug Grahn, was familiar with the crash because his dad was a Delta pilot at that time, Brennen said.

With the plaque already taken care of, Brennen reached back out to Delta for help with the luncheon. The company is providing support for that portion of the event Brennen said. Delta was contacted for an interview for this report and out of respect for the families, a spokesman deferred comments about the memorial to those organizing the event.

“They have been wonderful and recognize it’s a really important event,” Brennan said.