The unique real estate is among some 70 bunkers - both above and below ground - for which the government no longer wants to pay upkeep, the institute told daily Frankfurter Allgemeine Zeitung.
“The sales are not restricted, so anyone who is interested and has serious conversion plans can apply,” said Georg Schedler, who works at the institute's Kassel branch, where five bunkers will soon go on the market.
The secure spaces have been deemed unnecessary since the end of the Cold War, spokesperson for the Federal Office of Civil Protection and Disaster Assistance Ursula Fuchs told the paper.
“For current population protection scenarios like natural disasters, power outages and terror attacks, the existing structures are of limited suitability due to their technical outfitting and operational capabilities,” she said.
So far the state of Hesse has shown no interest in snapping up the bunkers, and it remains unclear whether private investors will make an offer.
“The upkeep of such bunkers is very pricey,” said Jürgen Sittig of the Kassel fire department, which the BImA commissioned to care for them. “The funding in the last few years has gone down repeatedly in the last years.”
Now the fire brigade receives between €10,000 and €20,000 per year to care for the city's eight bunkers – down from €51,000 in years past.
“With that amount of money it's hardly possible to keep the shelters dry,” he said.
But the poor state of the bunkers will likely be as much of a challenge to buyers as it has been for the city.
The walls of one four-floor bunker, built to hold 4,000 people during World War II near the Marien hospital in Kassel, are damp and covered with mould and cobwebs, the paper said.