Structural testing was conducted Wednesday on the 161-year-old Fire Island Lighthouse.

According to the National Park Service, there are cracks in the outer bricks and concrete coating of the tower. There's also a problem with moisture buildup.

Before anyone can figure out what to do about it, they have to better understand why it's happening. The tower is closed for a few weeks while testing is underway. Pieces of the tower are being pulled out so the materials can be examined more closely.

Each brick that's removed will be sent to a lab for testing. They're going to determine how strong they are, how much salt has been absorbed and how water moves through it. They're also taking off some of the outer coating.

Jim Dunphy, Fire Island National Seashore facility manager, says they're going to monitor the tower for a full year to see how it reacts to different elements. Once the information is collected and analyzed, a long-term restoration plan would be the next step.

The National Park Service says the tower should be back open in about three weeks.

In the meantime, the other lighthouse buildings are still open.