 Complete the following phrase:  Additional problems persisted, and in 1993, high levels of lead were discovered near the bridges towers. Further emergency repairs were undertaken in mid-1999 after small concrete shards began falling from the bridge into the East River. The concrete deck had been installed during the 1950s renovations and had a lifespan of about 60 years. The Park Row exit from the bridges westbound lanes was closed as a safety measure after the 