NEW YORK, Oct. 4 (Xinhua) -- Workers at Kaiser Permanente, the United States' largest health-care nonprofit organization, began a strike Wednesday morning that is expected to see more than 75,000 union members walk out of hospitals and medical offices after the company and labor negotiators failed to resolve a dispute over staffing levels.

"The Coalition of Kaiser Permanente Unions has described the work stoppage as the largest strike of health-care workers in U.S. history," reported CNBC, noting that the strike will target Kaiser hospitals and medical offices in California, Colorado, Oregon, Virginia, the District of Columbia, and Washington state. It began at 6 a.m. ET (1000 GMT) in Washington, D.C. and Virginia.

Other workers are scheduled to walk out at 6 a.m. local time in the remaining states. The strike is expected to last until Saturday morning. The striking workers include vocational nurses, emergency department technicians, radiology technicians, X-ray technicians, respiratory therapists, medical assistants, and pharmacists, among others.

The unions at Kaiser are demanding long-term investments to address a staffing shortage in addition to better pay and benefits. Caroline Lucas, executive director of the Coalition of Kaiser Permanente Unions, said the staffing crisis has led to unsafe working conditions and deteriorating care for patients.

"We continue to have front-line health-care workers who are burnt out and stretched to the max and leaving the industry," Lucas told local media. "We have folks getting injured on the job because they're trying to do too much and see too many people and work too quickly. It's not a sustainable situation."