Jerald Pasker, 32, and his son, Gary, 6, fell about 25 feet (7.5 m) after the father with the boy in his arms tried to step onto a forklift-supported pallet that kicked out, according to the Jones County sheriff's office.

The pair's 29 May fall occurred down a shaft onto a concrete floor at a Cascade area high-security communications facility that Pasker owns.

Pasker uses the forklift to lower equipment into an underground area.

The Paskers, who reside in Monticello, Iowa, were transported to the University of Iowa Hospitals and Clinics in Iowa City. The father absorbed the brunt of the fall, and the son escaped without serious injury.