SOUTH BURLINGTON, Vt. (AP) — Officials at a Vermont airport say a planned explosion at a rock quarry went awry and showered planes and cars with large rocks.

Burlington International Airport Manager Brian Searles says rocks hit four small airplanes, several vehicles and some buildings Wednesday. No one was hurt, but there was damage costing several hundred thousand dollars.

Some of the rocks were the size of microwave ovens.

The quarry is part of an area being readied for airport expansion.