SEATTLE — Several Western Washington public transportation agencies are dropping mask requirements after a federal judge struck down the Center for Disease Controls mask mandate on Monday.

Florida federal Judge Kathryn Kimball Mizelle said in the 59-page decision striking down the travel mask mandate that the CDC both exceeded its legal authority and failed to go through proper channels to put the rule in place.

As a result, the CDC late Monday said its order requiring masks on public transportation “is no longer in effect” and the agency will not enforce it. However, the CDC said it “continues to recommend that people wear masks in indoor public transportation settings at this time.”

Airlines were among the quickest to adapt to the new ruling, with Delta and Alaska in particular jumping on the opportunity to lift their mask rules.

“It has been a long 24 months with nearly constant change. I could not be prouder of our frontline employees who have handled every pivot focusing on safety and the care we’re known for,” said Max Tidwell, VP of safety & security at Alaska Airlines in a written statement. “We’re also thankful for our guests who remained considerate, patient and stood by us throughout every twist and turn.”

Sea-Tac Airport quickly followed suit, announcing Monday evening that masking would be considered optional going forward.

The TSA said in its statement that the CDC continues to recommend face coverings to protect against the coronavirus. Amtrak issued a stronger statement, saying that although they are no longer required of passengers and employees, “masks are welcome and remain an important preventive measure against COVID-19.”

Other forms of transportation are also joining in. Masks mandates are out at Washington State Ferries, Uber no longer requires masks as of Tuesday and Lyft soon followed suit, saying masks are now optional for riders and drivers.

Other public transportation agencies are split on the issue. Some, like Pierce Transit, quickly confirmed that masks will no longer be required on buses.

Contrast that with King County Metro, which initially claimed it would continue to require masks, but then switched course shortly afterwards. By Tuesday morning, the agency, along with Sound Transit, Kitsap Transit, Everett Transit, the Seattle Monorail and Seattle Department of Transportation were all dropping their mask requirements.

“While masks are no longer required on transit, riders are welcome to continue wearing face coverings if they wish,” the agencies said in a joint statement. “Please understand it will take time to update all of the announcements, signs, and other communications related to the federal mask mandate.”

Like Puget Sound’s transportation agencies, local leaders are also split on the issue. Some heralded the change as a sign that the pandemic is coming to a close. Others warned that looser restrictions might exacerbate climbing case counts.

“This is not a decision based on effectiveness or public health need, but administrative process,” tweeted Dr. Jeff Duchin, King County’s top health official. “Regardless of what happens with the federal mask mandate, covid cases are rising in many places & masking + other prevention steps continue to be important.”

It’s unclear if the Biden administration will appeal the decision. White House Press Secretary Jen Psaki told reporters Monday that Mizelle’s decision was “disappointing,” and the administration’s response is still under review and the “Department of Justice would make any determination about litigation.”