A contractor will pay $1 million to settle a civil case that it falsified test results for concrete panels it built for Phase 2 of the Silver Line Metro extension, the Justice Department announced Monday.

Universal Concrete Products Corp. and its president and co-owner, Donald Faust Jr., admitted no wrongdoing in agreeing to the settlement. However, Andrew Nolan, a former manager at the company, pleaded guilty in August to con­spir­a­cy to com­mit wire fraud for his role in fal­si­fy­ing test data to show that the con­crete had passed in­spec­tion and for or­der­ing oth­ers to do the same.

Universal Concrete manufactured the panels as part of a $6.1 million contract.

Problems with the concrete panels, installed at five of the six stations being built as part of the second phase of the $5.8 billion Silver Line rail project, were contained in a whistleblower lawsuit filed in federal court in Alexandria in 2016 by Nathan Davidheiser, a former lab technician at Universal Concrete.

Davidheiser alleged in the suit that he was fired after repeatedly raising concerns about the company’s manufacturing process. He filed his complaint under the federal False Claims Act, which allows whistleblowers to recover a portion of any money the government recovers on behalf of defrauded taxpayers. After the suit was unsealed in May, the state of Virginia and attorneys for the Justice Department intervened, filing a joint complaint against Universal alleging that it falsified documents to cover up problems with the panels.

Monday’s settlement signals the end of the government’s involvement in the suit, although Davidheiser’s claim that he was wrongly terminated will move forward, his attorneys said.

“He feels very vindicated by the news of the settlement, as he was the one who raised the concerns initially and it cost him his job,” said Nicholas Woodfield, one of Davidheiser’s attorneys.

In a statement, Universal Concrete said it “is pleased to close this case pursuant to the settlement agreement. While UCP was confident in its defense, the settlement amount is less than what legal and expert costs would have been through a trial. Settlement was the prudent course.”

Nolan’s attorney had no comment on the settlement.

The federal government, through the U.S. Department of Transportation, has provided nearly $2 billion in loans to pay for construction of the Silver Line’s second phase; Virginia has provided more than $300 million in funding.

Although the rail line will be operated by Metro once it is complete, its construction is being overseen by the Metropolitan Washington Airports Authority. The lead contractor is Capital Rail Constructors, a joint venture between Bethesda-based Clark Construction Group and Kiewit Infrastructure. Universal Concrete, based in Stowe, Pa., was a CRC subcontractor.

The contractors will pay the cost for replacement and treatment of the flawed concrete panels.

CRC, which was not part of the civil action, had no comment on Monday’s settlement.

Even so, the revelations contained in the suit have raised serious questions about CRC’s oversight of the rail project. The second phase of the Silver Line is 13 months behind schedule; officials continue to say it will open for passenger service in 2020.

In addition to problems with the concrete panels, there have been issues with cracks in the concrete girders that support elevated tracks near the Dulles Airport station. MWAA temporarily stopped work until those problems could be resolved.

Most recently, flaws were found in hundreds of concrete rail ties that MWAA and CRC remain at odds over how to fix. Construction of a rail yard to store trains, near Dulles Airport, also is significantly behind schedule — an issue that could delay the line segment’s opening.

The second phase of the Silver Line, which will extend Metro service to Dulles and into eastern Loudoun County, is one of the largest infrastructure projects under construction in the United States. The first phase opened in July 2014 and included five stations — four in Tysons Corner and one in Reston.

“MWAA and [the Justice Department] take the quality of the Silver Line very seriously and will continue to hold all of our contractors and subcontractors to the quality levels that will ensure safety and 100-year durability,” said Charles Stark, executive director of the Silver Line rail project. “MWAA will ensure that the actions necessary to deliver safety and 100-year durability will be taken by Capital Rail Constructors.”

Metro’s inspector general also is conducting a review of allegations contained in the whistleblower lawsuit.

Issues with the concrete panels became public in April, when Stark announced that the lead contractors had identified problems with precast panels installed at five of the six new stations that could lead to water seepage and premature deterioration of the station walls.

In all, 1,500 precast pan­els were said to be in ques­tion, and 20 percent con­tained flaws. The pan­els now re­quire a seal­ant to pre­vent wa­ter in­tru­sion and oth­er types of dam­age. That work was to be completed last year, but it has been delayed by weather issues, project officials said.

The government’s complaint alleged that from approximately October 2015 through June 2016, Nolan and company employees he supervised falsified test records so that it would appear that air content for the concrete panels was within the range required by the contract. Nolan allegedly falsified test records knowing that the general contractor for the project would reject the concrete had it known that it fell below that range.