If present, it will remain at the bottom of the sealed sumps below the floor of the mechanical room at the lowest cavern level. The room has elaborate sensing, control and exhaust systems. Air quality monitoring has shown no detectable levels of hydrogen sulfide anywhere in the storage buildings. The systems are totally separate. Sump pits are sealed and closely monitored.
Exhaust fans remove any hazardous gases.
The University continues to investigate a variety of solutions to the contaminated ground water. Remedies such as the installation of horizontal or a vertical well to collect the ground water are being discussed. While the University will continue to work with Minnegasco and the Minnesota Pollution Control Agency to resolve the issue as quickly as possible, it s a problem that requires a long-term solution. The University is anxious to have the gas holder cleaned up. This will be an expensive project and Minnegasco s contribution to the cost needs to be assured before the project can begin.