ALISO CANYON ( —  For the first time since the massive methane gas leak was finally capped nearly a year ago, the media was allowed to tour the Aliso Canyon Storage Facility near Porter Ranch.

The 2015 four-month natural gas leak, which scientists called the largest in U.S. history, displaced at least 7,000 Porter Ranch residents for months because the toxic fumes were making them sick.

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Ken Harris is the State Oil & Gas Supervisor and head of the Department of Conservation’s (DOC) Division of Oil, Gas, and Geothermal Resources.

“I appreciate how difficult it has been for them. I understand their concerns. We are trying to ensure that the facility or any facility in California never has an upset like this again. That’s our goal,” Harris said.

CBS2’s Randy Paige got a look at what Harris said was redundant safety systems – from multiple layers of pipes to sophisticated pressure monitors at each well.

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There were infrared cameras that can detect tiny amounts of methane gas and infrared instruments that keep watch along the borders of the facility.

Harris said 34 of the 114 wells there had passed rigorous safety inspections, and the natural gas storage facility will remain empty and off line until each of the wells either passes inspection, is temporarily sealed and placed off line or plugged and abandoned altogether.

“When we’re done, this will be a safe facility,” Harris said.

In a few months after a decision is made about the fate of each of the wells, a public meeting will be held to allow people who live near the plant to share their thoughts.

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Then state regulators will be asked to decide whether or not to allow methane gas back into the massive underground reservoir.