In addition to the dangerous environment, it's also likely to be contaminated with a lot of toxic stuff. In the closed German coal mines the pumps have to run 2

In addition to the dangerous environment, it's also likely to be contaminated with a lot of toxic stuff. In the closed German coal mines the pumps have to run 24/7 to prevent both the rising water from flooding the region* and the flame retardants and other poisons from reaching the surface waters. * some areas like the city of Essen have dropped by 16m, others up to 40m due to mining. Running the pumps to prevent flooding is considered part of the Ewigkeitskosten (eternal costs, see: https://de.wikipedia.org/wiki/Ewigkeitskosten https://de.wikipedia.org/wiki/Ewigkeitskosten ). edit: fixed numbers, added link