Explosives To Take Down Old Tappan Zee Bridge

TARRYTOWN, N.Y. (CBSNewYork) -- The old Tappan Zee Bridge is going out with a bang.

The take down is moving to Plan B, which will mean closing the Thruway this weekend and using explosives, CBS2's Tony Aiello reported Monday.

Plan A was to carefully dismantle what's left of the old bridge, which sits just south of the gleaming Governor Mario M. Cuomo Bridge. However, engineers have determined that what's left of the old span is so rickety, they have to move to Plan B, as in "boom," which we will hear on Saturday morning.

The problem was made public right after the new bridge opened in September. There was a loud popping noise from the old bridge, indicating the remnants of the east anchor span were under stress.

Engineers investigated and determined the span was unstable, so dismantling operations were halted. Now, it has been determined that the old span has to come down by a controlled explosion.

Experts say it's necessary to ensure safety of the work crews. Explosive charges will be used to cause the east anchor span to drop into the river.

It will be similar to the 2017 scene when explosives were used to take down the old Kosciuszko Bridge connecting Queens and Brooklyn.

Officials have denied that an alleged rush to complete the new bridge caused this situation with the old bridge. The advocacy group Riverkeeper says it has reviewed the explosive demolition plan and feels it minimizes impact on the environment and marine life, adding this is the best time of year for the operation to have the least impact on fish habitats.

The operation is planned for Saturday at 9:30 a.m. Traffic on the Thruway and the new Cuomo bridge will be closed in both directions for about 45 minutes. Officials say nearby residents will hear a boom similar to a fireworks show.

If the weather is inclement, the entire operation will be pushed to Sunday, Jan. 13.

For detailed information on how the controlled demolition will impact area roads, please click here.