Shortly after the first test, CERN said that an electrical connection between two magnets had melted, causing a "large helium leak" in the tunnel. "At no time was there any risk to people," the agency said at the time.

As part of the investigation, technicians brought the affected area of the collider's tunnel to room temperature and the involved magnets had to be opened for inspection. After the work is complete, the entire area will need to be recooled.

The faulty wiring issue arose two weeks after a was replaced in the machine.

Early in October, shortly after the problems were disclosed, a U.S. federal judge seeking to halt experiments in the Large Hadron Collider.

The civil suit called for more safety reviews to be done before any experiments could be conducted at the collider. Chief Judge Helen Gillmor wrote in her decision that the U.S. federal courts do not have jurisdiction over the European-based collider, even though the project received $531 million in U.S. funding. Gillmor concluded that the U.S. contribution was not a "major federal action" because it accounted for less than 10% of the cost to construct the collider.