Abstract: Employee #1 was cleaning the top 4- to 5-inch layer of solid sludge off a dairy farm lagoon using a Halla HE360LCH track hoe. There was approximately 5 feet of liquid dairy manure under the sludge. The track hoe tracks measured 12 ft from outside to outside of the tracks. The employee positioned the track hoe on a 14-ft-wide road adjacent to the lagoon, with the tracks parallel to a 5-ft vertical soil embankment. On the other side of the road, a 3-ft-high dirt wall prevented the positioning of the track hoe further away from the lagoon, and from setting the track hoe perpendicular to the lagoon. The 5-ft vertical soil embankment collapsed, and the track hoe rolled into the lagoon. The operator drowned when the liquid in the lagoon engulfed the cab. The area experienced heavy rains about one week earlier.