At least three patients died last year at a Southern California hospital in a bacterial outbreak suspected to have been caused by tainted medical scopes, according to a newspaper report Thursday.

Officials at Huntington Hospital in Pasadena confirmed in August that three patients were sickened but declined to say more about their condition. The hospital later told Olympus Corp., the scope’s manufacturer, of the deaths, the Los Angeles Times reported. The revelation came in the company’s report to federal regulators, which was obtained by the Times.

Hospital officials said this week that they believed patient privacy laws prevented them from telling the public that the unnamed patients had died.

Contamination of duodenoscopes, lightweight tubes threaded through the mouth into the top of the small intestine, has been linked to bacterial outbreaks that sickened dozens of patients in hospitals around the country. In an earlier similar outbreak at UCLA Ronald Reagan Medical Center, officials confirmed that patients had died.

It is still not clear how many patients may have been infected during the outbreak at Huntington or if only three died. The hospital will not say how many patients may have been exposed to the dangerous bacteria.

Olympus’ report to the U.S. Food and Drug Administration said that the three patients had been diagnosed with septicemia — a serious bloodstream infection — after undergoing treatment with a duodenoscope in mid-July 2015.

All three patients tested positive for a similar drug-resistant bacteria called pseudomonas. The hospital told Olympus that health authorities would determine the patients’ cause of death.

Peter Kaufman, a Los Angeles lawyer, filed lawsuits on behalf of three patients treated with the scopes at Huntington. Two of those patients died, he said, including 69-year-old Azniv Tavidaghian of Pasadena.

It is not clear if those patients are among the three in Olympus’ report.

Tavidaghian, who was suffering from cancer, had been treated twice with an Olympus scope before she died Aug. 11.

Kaufman said that doctors had told the Tavidaghian family that they were trying to determine why Azniv had died and couldn’t provide more information until the investigation was over.

Both Huntington and Olympus said they don’t comment on pending litigation.

An investigation into the suspected outbreak continues, said William Boyer, a spokesman for the city.

Last month, Rep. Ted Lieu, D-Torrance, released FDA data showing that as many as 350 patients at 41 medical facilities around the world had been infected or exposed to tainted duodenoscopes from January 2010 to the end of October 2015.