Hill Air Force Base officials have learned that dirt from a chromium-splotched trench was hauled from the base and dumped on private land before the contamination was discovered.

Hill spokesman Len Barry said the soil was dumped by a contractor on rural Davis County land with the permission of an owner who did not want to be identified. The dirt has been covered with plastic sheeting and will be removed for hazardous-waste disposal by early next week.Samples from the transported dirt are being tested to determine their chromium content, Barry said Friday.

Barry said he did not know how much soil was involved, but the dirt was removed from the base about March 1.

The soil came from a large trench being dug in the floor of the base's Building 225, a hangar where fighter and cargo airplanes are overhauled. The trench is for electrical, hydraulic and air lines used in the work.

Digging was stopped March 2 when yellow spots were noticed in the dirt. The discoloration was from chromate salt believed to have been formed by chromium from an old plating operation in the building.

Excavation resumed with precautions this week after the base's bio-environmental engineer determined the amount of chromium in hangar air and workers' urine was not cause for concern.

Barry said the Air Force found the displaced soil Thursday.

The Air Force and the contractor, Stevens Construction Inc. of Centerville, have reported no ill effects from the chromium on their workers.