Queens-Midtown Tunnel fully reopens with delays after water leaks inside
abc7ny.com

... MTA Bridges and Tunnels President Cathy Sheridan said the contractor drilled a roughly 2.5-inch hole into the cast iron liner above the exhaust duct, causing saltwater to leak into the tunnel.

"They were doing investigative drilling to determine geo-technical conditions in the river. This is an important part of the design process," said EDC Chief Infrastructure Officer Joshn Kraus.

The leak led to a temporary shutdown of both the north and south tubes as crews investigated the source of the leak, creating a traffic nightmare Wednesday afternoon. ...

OK, for me a 2.5 inch hole into a tunnel from the river above is a bit more than a "leak."

But, that's just me.