By creating cracks and holes, corrosion allows air to escape from the pipes instead of being forced through the pipe to create the desired sound. "The corrosion starts inside the lower part," Bergsten said, "and moves gradually upward inside the pipe toward the mouth area where sound is generated. If nothing is done, the pipe will collapse."

COLLAPSE is concentrating on lead pipes although the pipes are also made of wood and sometimes of other kinds of metal, including an alloy of lead and tin.

The project has its roots in the 1990s, when St. Jakobi's Church in L‹beck, Germany discovered that about 1,500 pipes in its 1467 Stellwagen organ in St. Jakobi's Church had been affected by such corrosion. Other churches, such as Santa Maria di Collemaggio in L'Aquila, Italy, inspected their organs and found evidence of similar damage.

This kind of corrosion is prevalent in continental Europe. In the United Kingdom, organs were generally made of tin, which was locally mined and cheap.

St. Jakobi's organist asked Bergsten to investigate the organ's damage, and COLLAPSE was the result of his request. The team is trying to identify the environmental factors that lead to corrosion in both old and contemporary organs, and also to find a treatment for affected instruments. The current treatment, called "amputation," involves cutting out the corroded pipe and replacing it.

One factor that came under scrutiny was central heating, the recent advent of which would explain why 500-year-old organs have only recently begun to deteriorate. Another factor might be corrosive pollutants in the air.