Some Lakewood residents are complaining about noise created by a rocket testing company.
One resident, Ed Swanson, said one test broke windows in his home and several others.
The tests are being conducted by Pioneer Astronautics, which has a contract with NASA.
Robert Zubrin, president of Pioneer, said during one test the concrete cell containing the rocket broke.
A small fire ensued but was quickly contained.
West Metro Fire Rescue said firefighters were called, but the fire had already been contained.
Cindy Matthews of West Metro said they have been working with Pioneer to make sure further tests are safe.
No charges will be filed.
Zubrin said he will pay for any damage.