Construction at a site for new condominiums in Norwich, CT got a little rocky to say the least.

Demolition blasting Friday sent rock flying almost 500 feet in the air and into cars and a nearby school yard. All the children were inside at the time.

City officials say the boulders were of various sizes and damaged seven cars.

A work site supervisor says a blasting mat that was supposed to cover the area lifted up allowing some rocks to be propelled. The city suspended the construction company's blasting permit until the operation is reviewed.

There were no injuries.