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. The information was released by the Metropolitan Transportation Authority, which is building the $4.45-billion Second Avenue Subway project.

Shea，Schiavone和Kiewit的合资企业已进行了“受控”爆炸，作为其合同的一部分一个970英尺长70英尺，高50英尺高的车站洞穴. The blast was to make room for a future escalator with only sound and vibration noticeable from the street.

Instead, smoke and debris escaped and shot up into the air and window glass shattered. Nobody was injured, but work will be halted until the team provides a decking system review and recommendations for how it will proceed.

MTA的Capital Construction Co.计划保留独立的安全顾问，增加保护性橡胶垫子，并“更多地参与了解各种方法是什么以及[承包商]将如何爆炸，”8月23日新闻发布会。

“当你垂直钻,cre能量ated should go laterally," he said. "In this case, it went vertically and actually aimed directly to the southeast corner of the 72^nd街甲板。他补充说，盖子应该吸收所有压力，但事实并非如此。

Horodniceanu说，要容纳爆炸的障碍板是1500磅。他说：“我相信它没有锚定在边缘。这是我们现在问的问题。”

The team had conducted 72 blasts previously without problems, he noted.

A call to the contractor was not immediately returned.