The Grand Princess cruise ship is being held off the coast of California after several passengers started to show coronavirus symptoms.
California Governor Gavin Newsom has declared a state of emergency and test kits are being flown to the cruise ship by helicopter.
The state’s first coronavirus death was an elderly passenger who was on the cruise ship last month.
The ship sailed from San Francisco to Mexico in February.
After some 2,500 passengers got off, the Grand Princess set sail on a new trip to Hawaii before being asked to test the most recent passengers.
Governor Newsom says authorities are also working to find the previous passengers and test them for COVID-19.
The Grand Princess is owned by Princess Cruises, which also runs Diamond Princess. That cruise ship was quarantined in February off the coast of Japan. Of the more than 3,700 crew members and passengers on the Diamond Princess, almost 700 people tested positive for COVID-19.