By Gianna Palmer

(Reuters) - Foul play was ruled out on Thursday in the deaths of a farm worker and his two sons who ended up buried deep in manure at a 2-million gallon waste pit on a Maryland dairy farm.

Maryland State Police said the bodies of Glen Nolt, 48, and his sons Kelvin Nolt, 18, and Cleason Nolt, 14, all of Peach Bottom, Pennsylvania, were found early Thursday at the Kennedyville, Maryland, dairy farm where they worked.

When the Nolts failed to return home on Wednesday evening to milk their own cows, concerned family members rushed to the Maryland farm, police said. They found Nolt's pickup truck and a tractor still running and parked beside the gigantic manure pit, which measures 300 feet by 150 feet and is 20 feet deep with steep sloping sides.

Evidence at the scene indicated they may have been working with a large auger, which is typically used to spray liquid manure on the ground, where it can dry before being spread onto farm fields, police said.

There was no evidence of foul play and an investigation into the apparent accident was ongoing, police said.

(Editing by Barbara Goldberg)