The well-known Sky Room restaurant and bar voluntarily closed for four days last week to implement a full-scale sanitation process in response to a norovirus outbreak, officials at The Sky Room and the Long Beach Environmental Health Bureau confirmed Monday.

Environmental Health Bureau Manager Nelson Kerr and the Centers for Disease Control (CDC) call the virus one of the “most common” outbreaks in the U.S., infecting 19 to 21 million people in the U.S. each year. The CDC states that anyone can be infected, often by touching an “infected person, contaminated food or water or by touching contaminated surfaces.”

“It’s been contained—at this point, it’s over,” Kerr said. “The Sky Room took the opportunity to go above and beyond in its response, according to CDC guidelines.”

Kerr said the restaurant closed from May 22 to May 26  and used the CDC guidelines required of cruise ships in response to a norovirus outbreak, which involve cleaning everything with a specific concentration of bleach and water.

According to Kerr, a total of 18 cases of the virus were reported among employees and patrons, with 15 probable cases and three confirmed. The three confirmed instances of the virus were reported among three employees of The Sky Room.

The Sky Room owner Jonathan Rosenson said, “Food safety is our number one,” Rosenson said, noting that the owners’ grandchildren have visited the restaurant since the outbreak. “We want people to come to our restaurant and have the best time ever.”