The victims were identified as Glen W. Nolt, 48, and his sons, Kelvin R. Nolt, 18, and Cleason S. Nolt, 14, all of the 900 block of Goshen Mill Road in Peach Bottom.
The three were reported missing Wednesday night at a large dairy farm in Kennedyville, Md., which is between Elkton and Chestertown, on the east side of the Chesapeake Bay.
The Nolts came to the farm to work each day in the early afternoon, and were last seen between 2 p.m. and 2:30 p.m. Wednesday, according to a press release from the Maryland State Police.
When the three did not arrive home to milk their dairy cows Wednesday evening, family members became concerned and drove to the Maryland farm.
People there found a tractor and the victims' pickup truck, which was still running. The vehicles were parked near a 2-million-gallon septic pond filled will manure, where the three were believed to have been working, police said.
Evidence from the scene indicated the three may have been working with a pump at the manure pit. The victims came to the farm each day and pumped liquid manure into a tanker. The tanker transported the manure to a field, where it was spread as fertilizer.
The manure pit is 20 feet deep, with steep sloping sides.
Vacuum trucks from a nearby farm were called in and began removing the manure from the pit as rescue personnel from multiple fire and rescue units searched for the three.
The body of the first victim, believed to be the father, was found submerged in the manure pit about 1:15 a.m. Thursday. The two other victims also were found submerged in the pit, one at about 4 a.m. and the other at 5:45 a.m.
A native of Lancaster County, Nolt was a farmer and a custom hauler, a family member said. He and his wife, Debbie, had five children, ranging in age from 4 to the late 20s, in addition to the two teens who died in the accident. He also had one grandchild.
He was the son of Martin and Eva Nolt, who also live in Peach Bottom, and has several siblings who live in Lancaster County.
The family attended Bethel Mennonite Church. The younger son attended Bethel Mennonite School.
"He was a good farmer, and he was a good man," said Nolt's brother, Nelson, of Berks County. "A very good father."
State police investigators are unsure how all three victims became submerged in the manure pit. At this time there is no evidence of foul play.
Nolt's brother said the family believes one of the three fell into the pit and the other two family members went to his aid, leading to their deaths.
All three were pronounced dead at the scene. Autopsies are pending.
Maryland State Police are continuing the investigation.