Bartlit emphasized in his letter Thursday that cementing failures are a known hazard in the oil industry, with specific tests such as a "negative pressure test" and "cement evaluation logs" designed to identify cementing problems.

CNN: STORY HIGHLIGHTS

But he said the lingering effects of superstorm Sandy and the administration's failure to broker a deal with the teachers' union on an evaluation plan have exerted significant pressure on the city's finances.

WSJ: Mayor's Final Budget Is Aided by Economy

The state education commissioner threatened Friday to withhold hundreds of millions of dollars in federal aid unless New York City showed it was prepared to put a new teacher-evaluation system in place, ratcheting up pressure on the city a day after a deal on new evaluations fell apart.

WSJ: State Warns School Aid Is at Stake