Sept. 30 (UPI) -- The Las Vegas Raiders are investigating why several players -- including starting quarterback Derek Carr -- were not wearing masks while they attended a recent charity event in Henderson, Nev.
Raiders tight end Darren Waller held the gala for his foundation Monday at the DragonRidge Country Club. Jason Witten, Jay Jones, Nevin Lawson, Foster Moreau, Hunter Renfrow, Derek Carrier and Nathan Peterman were among the other Raiders players who attended.
Photos and video footage from the event show players in a room with more than 50 people sitting at tables and not wearing masks, violating Nevada regulations for the coronavirus pandemic and a possibly violating NFL COVID-19 regulations.
The city of Henderson fined the DragonRidge Country Club on Tuesday for violating state regulations.
Raiders owner Mark Davis told reporters Tuesday the team is looking into the gathering.
"We obviously take responsibility for this," Davis told the Las Vegas Review-Journal. "You don't like seeing this.
"I don't know that it's actually been built into our memories that you have to wear a mask. Our organization takes it very seriously."
Davis donated to Waller's foundation, but did not attend the event. The foundation aids young adults addicted to drugs and alcohol.
"Guys have to be more stringent in fighting the virus," Davis told ESPN. "It's still our toughest opponent."
Raiders coach Jon Gruden on Sept. 22 was fined $100,000 for not wearing a mask during a game, a violation of league protocol. The NFL also fined the Raiders $250,000 for mask violations after their Week 2 win over the New Orleans Saints.
Gruden said he tested positive for COVID-19 in July before the 2020 NFL season started.
The NFL and players union announced Tuesday that three players and five personnel members from the Tennessee Titans tested positive for COVID-19. The Titans played the Minnesota Vikings Sunday in Minneapolis. Both teams have suspended in-person football activities until further notice.
NFL and players union rules limit player activity when they are away from their teams this season in an attempt to stop the spread of COVID-19. Players are not allowed to attend events that violate "local and state restrictions."
The Raiders will host the Buffalo Bills at 4:25 p.m. EDT Sunday at Allegiant Stadium in Paradise, Nev.