SEATTLE (AP) — The Seattle Department of Transportation now says reinforcing 16 bridges to better withstand earthquakes would cost hundreds of millions of dollars more than once expected.

The Seattle Times reports that instead of 16 bridges, the city now plans to complete seismic retrofits on 11, leaving locations like the Ballard and Fremont bridges off the list.

All told, the estimate for retrofitting the 16 bridges increased from $67 million to $731 million.

City transportation officials say deeper study of the bridges revealed expensive work related to the foundations that run underground and are surrounded by soil that can be at risk of liquefying during an earthquake.

With the specter of a big earthquake, local and state governments have been under pressure for years to do more to prepare. In Seattle, the cuts to seismic work are the latest trouble for the Move Seattle levy, a $930 million property tax package voters approved in 2015. City officials scaled back planned work under the levy after acknowledging costs were rising and City Hall had promised more projects than it could finish.

The city’s bridges have come into new spotlight this year, as the city shut down the West Seattle Bridge due to cracking and SDOT told city auditors the department should be spending at least five times as much as it currently spends on bridge maintenance. Earthquake improvements, though, received less outside attention and weren’t considered in the audit report.