The Boson Globe reported earlier this week that a Federal Highway Administration report found that the I-93 tunnel was structurally safe for the time being, despite the many leaks.

Efforts to patch up the leaks are underway, though according to the report the tunnel may always face some problems with leakage.

But the report did not suggest ways to fix the two highly defective panels of the tunnel, and it said that the steel beams of the tunnel’s roof may have long-term problems with corrosion.

According to the MTA website, there are two major components of the Big Dig, officially known as the Central Artery/Tunnel Project.

The first was the construction of the I-93 tunnel to replace the former six-lane elevated highway that had caused traffic congestion in downtown Boston.

The second component is the extension of Interstate 90—the Massachusetts Turnpike—from south of downtown Boston through a tunnel to Logan International Airport.

Started in 1991, the Big Dig is the largest and most technically difficult public works project ever undertaken in the United States. To date, it has cost over $14.6 billion.