When registered nurse Imelda Corea dons a fluorescent yellow sash and starts on her rounds distributing medicine to patients, her coworkers at the Kaiser Permanente Medical Center in West Los Angeles won’t speak to her.

The silent treatment is just fine with Corea. In fact, she calls it “sacred.”

It’s part of a Kaiser requirement, in place since 2008, that personnel must wear colored sashes when dispensing medication. They sashes are an easily recognized signal that a nurse is busy with work that requires special concentration, a simple tool to forestall interruptions and distractions that could lead to error.

The Kaiser program is just one of many at hospital across the country designed to reduce medical errors, which kill and estimated 210,000 to 440,000 patients annually, according to a report last year from the Affordable Care Act-funded Partnership for Patients.

The federal Centers for Disease Control and Prevention, which track leading causes of death, do not report on medical errors. But Sen. Barbara Boxer (D-Ca) pointed out recently that if such mistakes were included in the ranking, they’d be listed as the third biggest killer in the country, just behind heart disease and cancer.

In the months after implementing a series of safety steps that included the no-talking rule, Kaiser recorded that both interruptions and medication errors decreased by half.

In response to the Partnership report, Boxer’s staff asked 283 acute-care hospitals in California about what actions they had taken to prevent errors.

Some 149 responded, with protective measures that included hand-washing protocols to avoid infections, care practices designed to reduce the risk of pneumonia. Riverside County Regional Medical Center evaluated the likelihood that patients would fall and then monitored them accordingly.  At Cedars-Sinai Medical Center, the report said, nurses reduced bedsores by more than 70 by improving training and reporting methods for pressure ulcers.

Laura K. Nagel, Kaiser’s national medication safety strategy program leader, said Kaiser first used colored vests at its testing facility, but switched to sashes because they’re easier to carry, more easily adjustable to fit nurses of different body types, and less likely to come in contact with the patient or with medications.

The Ronald Reagan UCLA Medical Center reported an 18 percent reduction in surgical site infections from 2010 to 2013. Zachary Rubin, the Center’s medical director of clinical epidemiology and infection prevention, attributed this success to a variety of increased precautions.

For instance, the Medical Center prohibits the use of home-laundered scrubs, and bans doctors and other staff with open wounds, bandages or casts from scrubbing into surgeries.

Once a room becomes vacant, cleaning supervisors mark high-touch surfaces with ink that is only visible under ultraviolet light. They check again after janitors finish work to make sure those surfaces have been scoured, and use any oversights as training opportunities, Rubin said.

The Medical Center also added a potent tool in late 2012: a portable device that emits flashes of a different kind of ultraviolet light as the final phase of disinfecting rooms. The light floods the room, striking hard-to-reach surfaces where bacteria might lurk.

Boxer said she wants the federal government to encourage such practices, in part by instituting a standardized method to report medical errors and through increased legal protections for medical staff who report health risks.

“We cannot turn away from this challenge,” the senator said in prepared remarks at the Los Angeles event.

“If any one of us were on the street corner and saw someone about to step off the curb and get hit by a bus, what would we do? We would pull them back from disaster. We have that chance today. We have the opportunity to pull more than 200,000 people back from disaster every year by preventing medical errors.”