SAN FRANCISCO -- Tensions boiled over Thursday morning between security guards and striking workers at California Pacific Medical Center in San Francisco as the labor action entered its 32nd day with no end in sight.

Chanting workers confronted a bus of replacement workers, triggering a pushing and shoving confrontation with the security guards. Picketer Haydee Renderous told KTVU that one of her friends was struck and injured by a security guard.

"They were pushing us, kicking us," she said. "One of my friends was kicked in the stomach. When she fell down the guard hit her in the head. She was crying, and crying."

California Pacific spokeswoman Christine McMurry countered, claiming it was the strikers who had heightened tensions along the picket line.

"We're a hospital," she told KTVU. "We take care of patients. We have very sick patients inside. The strikers have beaten on patients' cars. They have spit in patients' faces. They have been very aggressive with employees, pushing them. I think we have shown remarkable restraint."

The labor dispute has grown more acrimonious as the days have rolled by.

On Sept. 3, the union gave eight hospitals operated by Sutter Health a 10-day strike notice. Although the hospitals are affiliated with Sutter Health, they each have their own governing boards and require contracts to be negotiated separately.

Contracts had expired at all the hospitals, including California Pacific Medical Center, Alta Bates Summit Medical Center in Oakland and Berkeley, St. Luke's Hospital in San Francisco and Eden Medical Center in Castro Valley.

The Service Employees International Union-United Healthcare Workers West Local 250 originally planned to strike all eight, but at the 12th hour decided to narrow the scope of the walkout to just California Pacific. Workers walked of the job on Sept. 12.

There have not been any contract talks between the two sides for weeks. Negotiations did not break down over wage demands, but stalled as union negotiators pushed for improved pensions, increased funding for training and education and a greater say in staffing.