Conservative group threatens to sue over Oregon's new mask rules The Oregon Health Authority announced the mandate May 18. Posted: May 27, 2021 8:11 AM Updated: May 27, 2021 12:52 PM Posted By: KGW Staff PORTLAND, Ore. — There is a new call for Oregon's governor to end the state's mandate requiring proof of vaccination for people to enter a business without a mask on. The Oregon Health Authority announced the mandate May 18 after the Centers for Disease Control and Prevention loosened mask requirements for people who are fully vaccinated. A conservative group called Freedom Foundation, which supports limited government, sent a letter to Gov. Kate Brown demanding that she lift the vaccine status check requirement. The letter also came with the threat of a lawsuit.