HIALEAH, FL — Registered nurses staged a one-day strike against Tenet Health hospitals in Florida, California and Arizona on Friday, demanding higher wages and better working conditions.

About 6,500 National Nurses United members walked out at 12 Tenet facilities after working without a contract for two years in Arizona and under expired contracts for months in California and Florida, the union said. They plan to resume working Saturday.

Members are also passing out leaflets in Texas, where contracts at two Tenet hospitals in El Paso expire later this year.

Yajaira Roman, a union leader and neurological intensive care nurse at Palmetto General Hospital in Hialeah, Florida, said that although the Tenet nurses want higher wages, they also want a lower patient-to-nurse ratio as a way to avoid burnout and improve care. For example, the union says Tenet assigns eight patients per nurse in Palmetto's surgical unit, double the level the union says research recommends.

"We are nurses -- we are really proud of what we do and we're happy that we're serving the community, but we want to do it in a way where when patients leave the hospital they are extremely satisfied," said Roman, a nurse for 18 years.

Tenet, which has 65 hospitals and 115,000 employees nationwide, issued a statement saying it has negotiated in "good faith" and it is disappointed the union chose to strike.

"While we respect the nurses' right to strike, patients and their loved ones can be assured that our patients will continue to be cared for by qualified replacement registered nurses and other caregivers," the Dallas-based company's statement said.

According to the U.S. Labor Department, almost 3 million registered nurses are employed nationally, with an average annual salary of $75,510. Florida's average RN salary is $66,210, Arizona's is $77,000 and California's is $106,950, tops in the nation. RNs typically have either an associate degree or bachelor's degree in nursing or graduated from a three-year program at a teaching hospital. They then must pass a state licensing exam.

The Tenet walkout is one of several strikes and organizing efforts nationwide as unions work to rebuild from a steep membership decline that began 50 years ago. Many are focusing on white-collar, female-dominated and service-sector industries such as health care, teaching, the media and hospitality instead of just blue-collar, male-dominated industries like manufacturing, where the United Auto Workers is striking against General Motors.

A recent Gallup poll showed Americans support unions by a 2-to-1 margin, up from a near even split 10 years ago and nearly the highest level since the 1960s.

