INDIANAPOLIS (AP) — Authorities say no one was injured when a network of pipes collapsed outside a Rolls-Royce aircraft-engine assembly plant in Indianapolis.

The collapse just before noon Friday left a line of large pipes and support structures toppled outside a building.

Rolls-Royce spokesman Joel Reuter says some of the pipes carry steam and one carries pressurized air used for testing jet engines.

Reuter says that pipe was funneling air into a building to test jet engines by simulating air flows at an altitude of 20,000 feet when the collapse occurred. He says that pipe may have been the cause of the collapse.

The Wayne Township Fire Department responded to the scene.

Rolls-Royce employs about 4,000 workers in Indianapolis who assemble engines for military and commercial aircraft.

Investigators working to determine cause of pipe structure collapse at Indianapolis Rolls Royce plant https://t.co/ceTYmru556 pic.twitter.com/zlz2K6s3T2

— CBS4 Indy (@CBS4Indy) August 4, 2017