This week, the U.S. Navy invited officials with the state health department and the Board of Water Supply to inspect its massive underground fuel tank storage tank facility at Red Hill.
They were able to see tank #5 firsthand.
It is the massive steel-lined tank where thousands of gallons of jet fuel leaked last month.
"There is some evidence of staining on a wall that was not there in early December before they started filling up the tank," said Steve Chang of the state health department’s hazardous waste branch.
Initially, the military estimated the spill was less than 20,000 gallons.
But Thursday, it said that number had been adjusted upwards to 27,000 gallons and added that because it was still investigating the discharge, the spill could even be larger.
Documents filed with the health department show that there had been a previous leak at the Red Hill facility in 2001-2002, with efforts to do follow-up monitoring.
The reports indicated that even back then, the state questioned whether the military’s monitoring system was adequate to protect the fuel from getting into our drinking water.
Recent tests have shown the water safe to drink, but the monitoring from previous spills in the past indicate some contaminants have been getting into the aquifer.
Chang says the military used to store various products in the 20 underground tanks--- from diesel, to aviation gas, to jet fuel.
"We have seen releases in the groundwater. There are very low levels but below action levels,” Chang said.
But Chang also said the Environmental Protection Agency is proposing new rules about underground storage tanks that could force the military to do even more to protect our drinking water.
"Changes in federal regulations in the next two years may require more monitoring to be done," Chang said.
But the fix might not be so easy dealing with 70-year-old tanks that stand 19 stores high and that are built in rock.
"It's not like being in soil in the streets. We are talking about solid rock formations. So, it’s going to be a challenge," Chang said.
Chang said his division sent a letter to the Navy on Friday.
The military is to submit a report within 90 days about how much fuel was actually lost and how it intends to clean it up.