She said the hospital would "reopen our operating rooms when we are confident they are safe for patient care," but she did not give a time frame for that to happen.
"We are very sorry for the impact the air quality issue in our operating rooms has had on our patients and families, and we are taking this situation very seriously," Bernal added.
Spokesperson Lindsay Kurs added in a subsequent statement, also emailed to CBS News, that Seattle Children's was continuing to "postpone or divert some surgical cases and move others to our Bellevue campus," but noted that doctors were still carrying out operations "in other areas of our hospital that have been determined to be safe for surgical care, like our cardiac catheterization facility."
Kurs said the hospital was "closely collaborating" with four other healthcare facilities in the area, "so that children in our region may continue to have access to the pediatric surgical services they need."
About 1,000 surgeries have been postponed, while more urgent procedures have been moved to either Seattle Children's other campus in Bellevue, or the other regional hospitals.
What is Aspergillus mold?
Bernal wrote in an email earlier that three patients were infected last year and three this year. The patient who died developed the infection in 2018.
"The six patients who developed Aspergillus infections were at higher risk of infection due to the types of procedures they had," Bernal said. "We are deeply saddened that one of these patients died."
No other information about the children and their conditions was released.
The Centers for Disease Control and Prevention has said Aspergillus mold can live indoors or outside and that most people breathe it daily without getting sick. But people with weakened immune systems are at a higher risk of developing infections in the lungs or sinuses from the mold. Aspergillosis can range from mild to serious, manifesting as an allergic reaction or infections in the lungs and other organs.
Last summer, after air testing at Children's detected the mold in two operating rooms and an equipment-storage room, those rooms were closed for three days and all operating rooms and storage rooms were inspected, Bernal wrote. "At that time, the issue appeared to be confined to the affected rooms and we took appropriate corrective actions," she wrote.
Children's also reached out to Public Health - Seattle & King County, which connected the hospital to the CDC because the federal agency had more expertise dealing with that kind of mold, public health spokesperson James Apa said. The CDC issued no report after it determined Children's was taking appropriate actions to investigate and address the problem, Apa said. Washington state Department of Health investigators also checked out the hospital and offered suggestions on how to improve air quality, which the hospital followed, Bernal wrote.
But the mold returned in 2019. In May, it was detected in four operating rooms and some equipment-storage rooms during a routine check, Bernal said.
After the hospital closed the four operating rooms May 18, some "urgent and less invasive procedures" were performed in the remaining 10 operating rooms, Bernal wrote in an email to The Times Tuesday.
Six days later, those operating rooms were also closed. Bernal said the additional closures were needed so crews could access and fix the hospital's air system. She would not say whether mold was detected in those rooms.