Nurses at Wilcox Medical Center on Kauai began a three-day strike Tuesday after negotiations with their employer reached an impasse.

The union nurses walked off the job and took to the sidewalks fronting the hospital at 7 a.m. Tuesday, wielding signs that said, “Safe Staffing for Kauai” and “Burnout Caused This Turnout.”

The Hawaii Nurses’ Association, which represents 159 members at Wilcox, said it was disappointed by the hospital’s refusal to implement better nurse-to-patient ratios. Wilcox, meanwhile, said it was disappointed with the strike, and still willing to negotiate.

“Wilcox Medical Center continues to provide uninterrupted, high-quality care for our community,” said Jen Chahanovich, Wilcox president and CEO, in a statement Tuesday. “The temporary workforce of experienced nurses transitioned smoothly into the medical center this morning and are now working alongside our Wilcox medical teams to care for our patients. We are fully staffed. No services are disrupted.”

She added that Wilcox remains committed to reaching an agreement for its nurses and planned to meet with HNA on Tuesday so they could benefit from a new contract as soon as possible.

The negotiations had been ongoing for four days with a federal mediator and had continued well into Monday night.

“We are still willing to ­negotiate in person every day for as long as it takes,” said Chahanovich. “We care for our nurses and value the role they serve on our team at Wilcox.”

HNA, meanwhile, said the impasse was over staffing the medical surgical unit at Wilcox at the same ratios as facilities on Oahu. She said nurses there experience ratios of 1 nurse to 6 or more patients per shift, while nurses on Oahu work with ratios of 1 nurse to 4 to 5 patients.

HNA is asking that the Wilcox nurses in the medical-­surgical unit care for no more than five patients at a time.

“The patients of Kauai deserve the same standard of care as those on Oahu,” said HNA President Rosalee Agas-Yuu in a statement. “The nurses want to end this double-standard.”

She said under management’s proposals, the Wilcox nurses in the hospital’s main medical-­surgical department would continue to care for six patients at a time and that this only affords them 10 minutes per hour to care for each patient.

“This unsafe staffing compromises the quality of care for patients,” she said. “By contrast, Kapi‘olani nurses take care of four or five patients at a time, which gives 12 to 15 minutes per patient. The extra two to five minutes per patient could save lives. This is what the nurses are fighting for and why they are willing to go on strike.”

The Kauai strike went forward the day after HNA’s scheduled strike at The Queen’s Medical Center in Honolulu and West Oahu was averted. The strike was canceled after a tentative agreement was reached in the early morning, just about five hours before nurses were scheduled to strike at 7 a.m. Monday.

Wilcox on its website said it has offered its nurses across-the-board raises totaling 14% over approximately 45 months, along with longevity pay.

Based on its current offer, registered nurses by the third year of the contract would earn a base salary of $138,000 to $161,000 for a three-day workweek, Wilcox said, along with bonuses.

Wilcox also said it offered a staffing matrix that can adjust to patients’ needs, along with a collaborative council to develop and maintain staffing standards.

“Patients are unique and require their own individu­alized care,” said Chahanovich. “Each medical center is different with its own support teams. Our Medical Surgical unit cares for a variety of conditions. That is why we are proposing to work together with our nurses to adjust staffing levels as needed through a staffing council using national standards. Patient safety is and always will be our top priority at Wilcox.”

Hawaii Pacific Health operates Wilcox, the largest medical center in Lihue, with an 18-bed emergency department serving as the isle’s primary stroke center, as well as Kapi‘olani Medical Center for Women &Children on Oahu, which houses the state’s only pediatric ICU in the state.

Kapi‘olani and HNA also clashed over staffing ratios, and reached an agreement on a new contract last fall after more than a year of talks — following two nurses strikes, a lockout and two rounds of intervention by federal mediators.

Negotiations between HNA and Wilcox for a new contract began in early May. Wilcox nurses have been working without a contract since Aug. 31. The strike is set to end Friday morning.