Seven people were killed and one injured critically today when a twin-engine plane bound from Kentucky to New York City crashed in dense fog in a park in a residential section of the Bronx.

Two teenagers were taken alive from the wreckage, but one died at Jacobi Hospital. A 14-year-old boy - the only survivor - was undergoing surgery and was said to be in critical condition.

An official at the Somerset-Pulaski airport in Somerset, Ky., from which the Mitsubishi turboprob amphibious plane took off, said it was carrying Sandy Guterman, owner of the Mt. Victory Coal Co. of Somerset and his family. The company owned the plane.

The official identified those aboard as including Guterma's wife and two children, and pilot Bob Holiday, all residents of Baca Raton, Fla. The identities of the other three victims were not immediately known.

The plane went down at 2:32 p.m., in Pelham By Park, two miles short of LaGuardia Airport and just 100 houses that look out on the park.

Officials speculated that the pilot - flying on instruments on his landing approach - may have become lost in thick fog that cut cisibility in the metropolitan area to virtually zero.

The tower at LaGuardia reported losing contact with the plane just one minute before the crash.

Joseph Verdi, who lives across the street from the crash site, said, "I heard a noise just about 2:30 p.m. and went out and there was aplane right inside the fence of the park, where the cops keep their horses. It was smoking and flaming and then I saw the firemen come."

Mrs. Nicholas Augresani said she had just put on a pot of coffee to share with a friend when she heard an explosion. "It crashed in the park," she said. "Right across from my house. We were just sitting down at the table and we heard theis explosion. We ran outside and there was a mess of smoke - a wing was sticking up in the air."