(Richard Tsong-Taatarii/Star Tribune via Associated Press)

A construction worker died after falling 50 feet off the roof and into a snow gutter on the new Minnesota Vikings stadium in Minneapolis on Wednesday, the Star Tribune reports.

A second man was also injured and remains in serious condition at a local hospital, however, how he got hurt is unclear, according to Mortenson Construction, the general contractor for the project.

The workers, who were contractors from Berwald Roofing, were working on the north side of the building, according to ESPN.

Regarding the worker who fell and died, officials say the cause of the tumble is unclear, including whether the unnamed individual was wearing a harness or taking any other safety precautions. Berwald Roofing has been cited and fined before for its workers not following proper safety protocols, the Star Tribune reports.

“Today is an extremely sad day for the Minnesota Vikings organization and the entire stadium team,” the Vikings said in a statement posted to the team’s Web Site on Wednesday afternoon. “Our sincere thoughts and prayers go out to the family and friends of the individual who passed away, the worker who remains hospitalized, and the more than 1,000 dedicated construction workers who are on the site every day and are also affected by this accident.”

The stadium, which is scheduled to open during the 2016-17 NFL season, halted construction on Wednesday, but it could start again as soon as Thursday, according to Mortenson Construction.

This is the first death of a worker connected with the new U.S. Bank Stadium, but not the first of the stadium’s problems. Last year, the Audubon Society complained over the type of glass chosen to construct some of the stadium’s walls and the roof, noting it was potentially dangerous to birds.

[Audubon Society calls new Vikings stadium a ‘death trap’]

Stadium construction has long been a dangerous business. In 2013, two workers died while building Levi Stadium outside of San Francisco, where the 49ers play. In 1999, three workers died after a 567-foot crane collapsed during construction of Milwaukee’s Miller Stadium, home of the Brewers.