While the cruise ship industry is struggling to stay afloat and the state of Florida is suing the U.S. Centers for Disease Control (CDC) to force it to allow cruise operators to sail again, two Democratic U.S. senators are calling for the agency to keep the industry locked down. Connecticut's Richard Blumenthal and California's Doris Matsui wrote to the CDC's director urging her to reject calls to open the cruise industry for business, saying a "premature resumption of cruise ship operations ... could threaten public safety and increase the spread of the coronavirus." Image source: Getty Images. Cruise operators Carnival (NYSE: CCL)(NYSE: CUK), Norwegian Cruise Line Holdings (NYSE: NCLH), and Royal Caribbean (NYSE: CCL) have been waiting for the CDC to amend its conditional sail order (CSO), which essentially prevented them from accepting passengers. When the CDC failed to provide clear guidance for the industry last month that would allow them to set sail again, Florida Gov. Ron DeSantis said his state would sue over its "arbitrary and capricious" actions. Cruise operators are taking a proactive approach. Seizing upon the conflicting guidance the CDC has issued saying people who are vaccinated can travel, Norwegian Cruise Line submitted a proposal to the CDC asking it to lift the CSO for its ships because it is mandating all crew and passengers be vaccinated before boarding. While ostensibly awaiting approval from the agency, the cruise operator says it will resume voyages beginning July 4. The two senators, though, say "Failing to adhere to [the CDC's] guidance could create unsafe conditions that jeopardize public health." Last November, they tried to prevent the CDC from modifying its previous no sail order to a conditional one. The effect of the CSO, though, was essentially the same. 10 stocks we like better than Norwegian Cruise Line HoldingsWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Norwegian Cruise Line Holdings wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of February 24, 2021 Rich Duprey has no position in any of the stocks mentioned. The Motley Fool recommends Carnival. The Motley Fool has a disclosure policy.Source