The death of one roofer and a serious injury to another shut down construction of the Minnesota Vikings stadium on Wednesday, leaving the massive project eerily empty for the rest of the day as an investigation was launched.

A somber John Wood, senior vice president of Mortenson Construction, whose corner office windows overlook the site, called it a "very tragic day."

"When something like this happens, it hits people very hard," he said.

Work on the $1.1 billion stadium resumed Thursday morning.

Wood didn't identify the man who died, but a source confirmed that he was Jeramie M. Gruber, 35, of Northfield.

The two workers, employees of St. Paul-based Berwald Roofing Co., started their day at 7 a.m. along with some 1,200 others at the site. At 7:45 a.m., Gruber fell about 50 feet from the edge of the north side of the roof into a snow gutter. He was dead upon arrival at Hennepin County Medical Center.

At the time of the accident, the two roofers were performing a "fairly conventional" installation, Wood said. Details weren't available about their precise location, whether a supervisor was nearby or whether the accident was seen by colleagues. Wood also couldn't say whether the two workers were wearing safety harnesses, a requirement for anyone working in certain elevated areas.

In the past five years, Berwald, which has a $3.4 million contract on the stadium, has received nine worksite citations for serious violations during six inspections, public records show. Fines totaled more than $12,500.

The majority of the violations were for workers failing to use safety harnesses or being protected from falls by guardrails. The heftiest fine, $2,200, was based on a worksite inspection in September 2013, when an employee worked in a "hoist area" 6 feet or higher without protection from a harness or guardrail. Some of the unprotected workers referenced in the inspections were on low- to steep-slope roofs or on a level walking surface at heights of 6 to 10 feet or more.

Gruber, who was married, went to Faribault High School, according to his Facebook page. Late Wednesday, condolences poured in to his relatives' pages, speaking of his work ethic and love of fishing. His mother-in-law posted a photo of him smiling and holding a big fish, saying, "My dear sweet son-in-law, we are all going to miss you, now and forever."

Family members could not be reached for comment.

The other worker, who was seriously injured while on the roof, was not identified.

In a written statement, Berwald's owners said: "Today's events have caused great sadness to everyone in our company's family." They declined further comment, but issued a statement later saying that the injured worker was in stable condition. Berwald did not reveal the worker's name or the nature of his injuries.

Rescue crews extricated both men from the U.S. Bank Stadium building, which is about 300 feet tall at its highest point.

Gruber's death was the first at the stadium site, which is the largest public-private project in state history.

The Minnesota Occupational Safety Health Administration has conducted 16 compliance inspections at Mortenson worksites in the past five years, agency spokesman James Honerman said. The company received no citations or penalties.

Mortenson built Target Field in downtown Minneapolis and TCF Stadium at the University of Minnesota, and it renovated St. Paul's Xcel Energy Center without a worker's death.

Heavy construction of the sort involved in building stadiums carries risks. Two workers were killed during the construction of the San Francisco 49ers' $1.3 billion stadium in Santa Clara, Calif. A 63-year-old worker was killed in an elevator shaft accident in June 2013, and a few months later a delivery driver died when a bundle of rebar he was unloading fell on him.

Until Wednesday, work on the stadium had been largely smooth. In March, high winds blew down scaffolding on the edge of the project, damaging the roof of a trailer, but no one was hurt. In 2014, demolition of the Metrodome was temporarily stopped for an investigation when a piece of the building unexpectedly fell out of sequence. No one was hurt.

Work at the site is likely to resume Thursday, a Mortenson spokesman said Wednesday evening.

'All a little traumatized'

Across the street from the stadium site, news of a worker's death sent a shock wave through the project headquarters of Mortenson, a multigenerational family business that has been so publicly mindful of safety that its workers must use the crosswalk to get to the site and they won't walk against the light.

Since the 32-year-old Metrodome was torn down in early 2014, the new building has risen smoothly under Mortenson's orchestration, hitting daily benchmarks and deadlines for progress. A week ago, the first of some 65,000 purple seats was put into place. A topping-off ceremony is planned for September. The roof is on track to be completed in November. The entire building remains on schedule to open next summer for the 2016 NFL season.

In the hour after the accident, workers in their bright yellow safety vests, heavy boots, well-worn jeans and hard hats walked somberly from the site, heading home. By midday, the steel gates at the site's main entrance were closed, and police cars guarded the perimeter.

As apprentice electrician Coshay Murray waited to get picked up, he said, "We're all a little traumatized today."

Condolences to the families of the dead and injured came from the Vikings, the Minnesota Sports Facilities Authority, Gov. Mark Dayton and U.S. Bank. Vikings coach Mike Zimmer said, "It's a sad day for us. Our prayers and thoughts go out to the families."

Late in the day, Angela Strong of St. Paul and her 11-year-old daughter, Kyra, laid flowers at the site.

"We forget how much danger is involved" in the work," said Strong, a Vikings fan.

Star Tribune staff writers Paul Walsh and Richard Tsong-Taatarii contributed to this report.