An Associated Press investigation has found government reports about dozens of offshore oil wells where cementing failed, as it may have in the Gulf of Mexico disaster.
The AP review of federal accident and incident reports implicates cementing at least 34 times since 1978.
Many of the reports identify the cause simply as "poor cement job."
Yet federal regulators give drillers a free hand in this crucial safety step. Much tougher government standards exist on cementing work for roads, bridges and buildings.
Federal regulators do not regulate what type of cement is used. Instead, they leave it up to oil and gas companies, and recommend they simply follow guidelines of a petroleum trade group.
Investigators are focusing on cementing as one likely cause of the Deepwater Horizon explosion.