• Construction of a subway station on the east side of Manhattan ion New York City was supposed tom produce only noise and vibration at street level, but rock and smoke erupted instead.
• Investigators are looking at the angle at which holes were drilled as part of the explanation for the blast that broke store windows.
• The probe also is looking at how decking was done in the project in which a joint venture of Shea, Schiavone and Kiewit was creating space underground for a escalator.

From the article:

Holes drilled at a 30-degree angle rather than vertically, plus inadequate decking, contributed to the Aug. 21 subway station project excavation blast that broke several store windows on the east side of Manhattan in New York City, according to preliminary investigation results. ...